Covetic Material

Abstract

To provide compositions composed of metals infused with nanoscale-sized carbon particles, featuring excellent physical, chemical, and electrical properties.SOLUTION: A composition of a material comprises one or more particles. At least some of the one or more particles independently comprise a metal lattice comprising one or more coherent and flat layers of graphene disposed within the metal lattice. The metal lattice comprises one or more metals selected from the group consisting of aluminum, copper, iron, nickel, titanium, tantalum, tungsten, chromium, molybdenum, cobalt, manganese, niobium, and their combinations.SELECTED DRAWING: Figure 20A2

Description

[Technical field]

[0001] Related Applications This application is a continuation-in-part of U.S. application Ser. No. 16 / 460,177, filed July 2, 2019, and entitled "PLASMA SPRAY SYSTEMS AND METHODS," which claims priority to U.S. Provisional Application No. 62 / 720,677, filed August 21, 2018, and entitled "PLASMA SPRAY SYSTEMS AND METHODS," and also claims priority to U.S. Provisional Application No. 62 / 714,030, filed August 2, 2018, and entitled "PLASMA SPRAY This application claims priority to U.S. Provisional Application No. 62 / 903,649, filed September 20, 2019, and this application claims priority to U.S. Provisional Application No. 62 / 868,493, filed June 28, 2019, and this application claims priority to U.S. Provisional Application No. 62 / 839,995, filed April 29, 2019, and this application claims priority to U.S. Provisional Application No. 62 / 797,306, filed January 27, 2019, all of which are hereby incorporated by reference in their entirety.

[0002] FIELD OF THE DISCLOSURE This disclosure relates generally to the preparation and use of covetic materials. [Background technology]

[0003] The term Covetic materials refers to metals fused with carbon particles of nanoscale dimensions. Covetic materials are desirable in a variety of applications because they possess many physical, chemical, and electrical properties that exceed the capabilities of conventional non-carbon fused materials. However, conventional Covetic material manufacturing techniques result in Covetic materials that fall short of achieving many of the physical, chemical, and electrical properties.

[0004] Even in the face of a strong desire for materials exhibiting the above physical, chemical, and electrical properties, numerous technical challenges have hindered the development of technologies for the fabrication and use of covetic materials, which stem from several areas, including (1) the difficulty of combining analytical methods required to measure carbon content for individual compounds with a high degree of specificity with microstructural or nanostructural characterization methods, (2) the relatively high variability of carbon content distributions observed in samples produced to date, (3) variability and potential unpredictability in property measurements, and (4) uncertainty regarding the exact scientific mechanisms responsible for the strong bonding observed between the carbon particles and the matrix surrounding them.

[0005] Conventional metal melting methods used to produce Covetic carbon metal composite alloys suffer from inconsistent conversion yields, which contribute to the wide variation observed in the properties of the resulting materials. For example, irregularities in carbon distribution in the melt often result in undesirable agglomerate formation and clustering. Such irregularities in carbon distribution in the metal can lead to the formation of cracks and pores that ultimately cause premature failure of the resulting material. Additionally, the high solubility of carbon in the metal can result in uneven carbon growth (e.g., thicker) at the metal surface as the metal cools and solidifies. Carbon solubility can also be higher near the free surface than in the bulk of the metal, which, combined with the interfacial energy at the melt-air interface, favors undesirable precipitation at the melt-air interface.

[0006] Conventional heat-assisted metal melting processes for producing Covetic carbon-metal composite alloys currently do not allow for the amenability of tailoring process conditions such that the resulting Covetic material exhibits a desired tailored or targeted set of properties. The inability to control process conditions such that the resulting Covetic material exhibits a tailored set of properties leads to a corresponding inability to apply the Covetic material to specific applications that require such a specific set of properties. What is needed is a technique for producing Covetic material products that exhibit a range of tailorable properties. What is further needed is a Covetic material product that can be used in a wide range of end use areas and applications, such as business-to-business or business-to-consumer applications, ranging from material reinforcement to improved longevity performance. Summary of the Invention

[0007] This Summary is provided to introduce selected concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. Moreover, the systems, methods, and devices of the present disclosure each have multiple innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0008] Various embodiments of the inventive subject matter disclosed herein generally relate to apparatus, methods, and various compositions of carbon metal composite materials. Apparatus related to the controlled utilization of plasma spray torch apparatus to produce various carbon metal bond compositions, generally and in this disclosure, referred to as "Covetic materials."

[0009] One configuration of the plasma spray torch is embodied as an apparatus comprising a reaction chamber configured to receive a hydrocarbon process gas mixed with a plurality of molten metal nanoscale particles, a microwave energy source operably coupled to the reaction chamber to provide power to the reaction chamber, and a controller regulating the microwave energy source to create conditions in the reaction chamber such that the hydrocarbon process gas dissociates into its constituent carbon atoms and single layer graphene (SLG) or few layer graphene (FLG) grow from the carbon atoms on the molten metal nanoscale particles to form a plurality of carbon metal nanoscale particles. In some configurations, the conditions in the reaction chamber result in: (i) a first temperature at which the carbon atoms dissolve into the molten metal nanoscale particles, and (ii) a second temperature at which at least a portion of the dissolved carbon atoms associate with the molten metal in a crystallographic arrangement. Some configurations of the apparatus utilize a cooling zone to cool the plurality of carbon metal nanoscale particles into a powder that is collected and stored in a containment vessel juxtaposed near the reaction chamber.

[0010] The details of one or more embodiments of the subject matter described in this disclosure are set forth in the accompanying drawings and description below. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. It is noted that the relative dimensions of the following drawings may not be drawn to scale.

[0011] Embodiments of the subject matter disclosed herein are illustrated by way of example and not intended to be limited by the figures of the accompanying drawings. Like numerals refer to like elements throughout the drawings and specification. It should be noted that the relative dimensions of the following drawings may not be drawn to scale. Copies of this patent or patent application publication with color drawing(s) may be obtained from the U.S. Patent and Trademark Office upon request and payment of the necessary fee. [Brief description of the drawings]

[0012] [Figure 1A]FIG. 1 is a comparative diagram illustrating two different Covetic material formation techniques and example materials resulting from each according to some embodiments. [Figure 1B] A high resolution transmission electron microscope image 114 and a high resolution energy dispersive X-ray analysis image 116 are presented according to some embodiments. [Diagram 2] 1 depicts a manufacturing process for growing graphene on small molten particles according to one or more of the disclosed embodiments. [Diagram 3] FIG. 1 depicts a plasma energy diagram showing how a pulsed microwave energy source can be used to grow graphene on small molten particles in accordance with one or more of the disclosed embodiments. [Figure 4] 1 depicts an electronic temperature control technique used to grow graphene on small molten particles according to one or more of the disclosed embodiments. [Diagram 5] FIG. 1 illustrates a twin plasma torch apparatus used to grow graphene on small molten particles according to one or more of the disclosed embodiments. [Figure 6] FIG. 1 illustrates a pulsed microwave plasma spray torch apparatus adapted to grow graphene on small molten particles according to one or more of the disclosed embodiments. [Figure 7] FIG. 1 depicts an intersection of common areas of inventive subject matter relating to Covetic bodies (or related materials), plasma torch spraying, and / or tightly composite carbon coatings, according to one or more of the disclosed embodiments. [Figure 8A] FIG. 1 is a schematic diagram depicting a plasma spray process used to spray carbon particles onto small molten particles according to one or more of the disclosed embodiments. [Figure 8B] FIG. 1 is a schematic diagram depicting a plasma spray process used to spray carbon particles onto small molten particles according to one or more of the disclosed embodiments. [Figure 9]1 is a scanning electron microscope image showing the effect of thermally spraying carbon particles onto small molten particles according to one or more of the disclosed embodiments. [Figure 10] FIG. 1 shows a depiction of a graphene growth temperature profile and a binary phase diagram according to one or more of the disclosed embodiments. [Figure 11] FIG. 1 is a cross-sectional view of a plasma flame device according to one or more of the disclosed embodiments. [Figure 12] 1 depicts a pulsed microwave process flow used in growing graphene on small molten particles according to one or more of the disclosed embodiments. [Figure 13] FIG. 1 is a perspective view of a pulsed microwave plasma spraying waveguide apparatus used to grow graphene on small molten particles according to one or more of the disclosed embodiments. [Figure 14] FIG. 1 is a schematic diagram of a microwelding technique used to grow graphene on small molten particles, according to one or more of the disclosed embodiments. [Figure 15] FIG. 1 is a schematic diagram of a plasma spray apparatus in a coaxial configuration according to one or more of the disclosed embodiments. [Figure 16] FIG. 1 is a schematic diagram of a plasma spray apparatus illustrating the evolution of a material by processing it through a series of non-equilibrium energy states in accordance with one or more of the disclosed embodiments. [Figure 17] 1 depicts a surface wave plasma system for growing graphene on molten particles according to one or more of the disclosed embodiments. [Figure 18A1] 1 depicts various configurations of a plasma spray reactor according to one or more of the disclosed embodiments. [Figure 18A2] 1 depicts various configurations of a plasma spray reactor according to one or more of the disclosed embodiments. [Figure 18B] 1 depicts various configurations of a plasma spray reactor according to one or more of the disclosed embodiments. [Figure 18C]1 depicts various configurations of a plasma spray reactor according to one or more of the disclosed embodiments. [Figure 18D] 1 depicts various configurations of a plasma spray reactor according to one or more of the disclosed embodiments. [Figure 19] FIG. 1 depicts energy versus time between pulse on and pulse off in accordance with one or more of the disclosed embodiments. [Figure 20A1] FIG. 1 depicts the organometallic bond that occurs when carbon and copper are combined using a plasma spray torch, according to one or more of the disclosed embodiments. [Figure 20A2] FIG. 1 depicts a gradient composition applied to a substrate material and shows multiple (e.g., three) material property zones according to one or more of the disclosed embodiments. [Figure 20B] FIG. 13 is a material evolution diagram depicting the multi-layer stack configuration that occurs when carbon is added to bulk aluminum, according to one or more of the disclosed embodiments. [Figure 21A] According to one embodiment, an apparatus for thermally spraying a molten mixture of materials onto a substrate is depicted. [Figure 21B-1] 1 depicts a method of thermally spraying a Covetic material onto a substrate according to one or more of the disclosed embodiments. [Figure 21B-2] 21B-1 depicts a method of thermally spraying a Covetic material onto a substrate according to one or more of the disclosed embodiments. [Figure 21C] FIG. 1 is a schematic diagram of a plasma spray process used to spray a coating according to one or more of the disclosed embodiments. [Figure 22A] 1 depicts an apparatus for enveloping carbon particles with molten metal, according to one or more of the disclosed embodiments. [Figure 22B-1] 1 depicts a method for enveloping carbon particles with molten metal, according to one or more of the disclosed embodiments. [Figure 22B-2] FIG. 22B-1 depicts a method for enveloping carbon particles with molten metal according to one or more of the disclosed embodiments. [Figure 23A] 1 depicts an example deposition technique according to one or more of the disclosed embodiments. [Figure 23B] 1 depicts an example deposition technique according to one or more of the disclosed embodiments. [Figure 23C] 1 depicts an example deposition technique according to one or more of the disclosed embodiments. [Figure 23D] 1 depicts an example deposition technique according to one or more of the disclosed embodiments. [Figure 24] A and B depict conventional deposition techniques for placing material onto a substrate according to one or more of the disclosed embodiments. [Diagram 25] 1A and 1B depict exemplary deposition techniques that result in covalent bonds to a substrate surface according to one or more of the disclosed embodiments. [Figure 26A] FIG. 1 is a schematic diagram illustrating how covalent bonds are formed between sites in the squares of the face-centered cubic structure of aluminum and sites in the hexagons that occur in certain crystallographic structures of carbon. [Figure 26B] FIG. 1 is a schematic diagram illustrating how covalent bonds are formed between sites in the squares of the face-centered cubic structure of aluminum and sites in the hexagons that occur in certain crystallographic structures of carbon. [Figure 26C] FIG. 1 is a schematic diagram illustrating how covalent bonds are formed between sites in the squares of the face-centered cubic structure of aluminum and sites in the hexagons that occur in certain crystallographic structures of carbon. [Figure 26D] FIG. 1 is a schematic diagram illustrating how covalent bonds are formed between sites in the squares of the face-centered cubic structure of aluminum and sites in the hexagons that occur in certain crystallographic structures of carbon. [Figure 26E] FIG. 1 is a schematic diagram illustrating how covalent bonds are formed between sites in the squares of the face-centered cubic structure of aluminum and sites in the hexagons that occur in certain crystallographic structures of carbon. [Figure 27A] 1 depicts an example apparatus for producing powdered Covetic material according to one or more of the disclosed embodiments. [Figure 27B1]1 depicts an exemplary fluidized bed apparatus for cooling and handling powdered cobetic material in a fluid, according to one or more of the disclosed embodiments. [Figure 27B2] 1 depicts an exemplary fluidized bed apparatus for cooling and handling powdered cobetic material in a fluid, according to one or more of the disclosed embodiments. [Figure 27C] FIG. 1 is a schematic diagram of a plasma spray process used to produce powdered Covetic material according to one or more of the disclosed embodiments. [Figure 28-1] 1 depicts a method of making components from powdered Covetic material using injection molding techniques, according to some embodiments. [Figure 28-2] 28-1 depicts a method of making components from powdered Covetic material using injection molding techniques, according to some embodiments. [Figure 29] 1 illustrates various properties of Covetic materials. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Aspects of the present disclosure relate to an approach to producing Covetic materials using thermal spray techniques rather than by mixing carbon-based materials into the bulk of a molten metal slurry. Some embodiments relate to techniques that reduce the dimensions of interstitial carbon structures to the nanometer (nm) scale. The accompanying figures and discussion herein provide example environments, example systems, and example methods for producing "Covetic" materials, which imply high concentrations (>6 wt%) of carbon, as generally understood and defined herein, incorporated into the metal (or metal-containing material) in a manner that does not cause carbon to separate during melting or magnetron sputtering. The resulting material has many unique and improved properties over the base metal from which it is made. Carbon is dispersed in the metal matrix in multiple ways that contribute to improved material properties. Carbon bonds very strongly with Covetic materials and often withstands many standard methods of detecting and characterizing their shape. The inclusion of nanoscale carbon increases the melting point and surface tension. Covetic bodies have higher warm and cold work strength.

[0014] Identification and significance of problems and opportunities Metal matrix composites can be composed of (at least) a metal or metal alloy (referring to metals made by combining two or more metallic elements, especially to increase strength or corrosion resistance) matrix in combination with stronger elastic ceramic, carbon-based reinforcements, or microfillers in the form of continuous or interrupted fibers, whiskers, or particles. The size of the reinforcement is important, as micron-sized reinforcement metals can exhibit acceptable levels of improved strength and stiffness over the base alloy. Nevertheless, due to undesirable agglomeration between particles during processing, such reinforcements may also be associated with undesirable poor ductility and undesirable low yield strength, machinability, and fracture toughness at the load limit. In order to avoid premature cracking and other drawbacks of metal matrix composites containing incompatible micron-sized reinforcements, it may be necessary to reduce the size of the reinforcing phase to the nanometer scale. Furthermore, a method is needed whereby the reinforcing phase is incorporated into the metal alloy matrix.

[0015] Significant increases in mechanical, thermal, electrical, and tribological properties (indicative of the science and engineering of interacting surfaces in relative motion) have been observed corresponding to the addition of the carbon-based reinforcements described above. Of note, such properties may change and / or improve as the size of the reinforcement decreases from the micron scale to the nanoscale (e.g., <100 nm) due to increased cohesive forces between the matrix and the particles. The improved properties may be due to the formation of strong interfaces that promote efficient strengthening mechanisms. Increases in tensile and yield strength have been reported for nano-sized particles (~20 nm) versus micron-sized particles (~3.5 μm), although for the same order of magnitude, the volume loading of nano-sized particles is smaller compared to micron-sized particles. Thus, past techniques may not be able to provide reinforcement at the nanometer scale. Thus, there is a current need to reduce carbon structures containing interstitial vacancies to the nanometer scale.

[0016] Microwave (MW) Plasma Torch Reactor Using a microwave (MW) plasma torch reactor, pristine 3D few-layer graphene (FLG) particles can be continuously, e.g., in-flight, nucleated in an atmospheric pressure vapor stream of carbon-containing species, such as methane gas, from an initially synthesized carbon-based or carbon-containing "seed" particle. As dense, highly structured, tunable 3D mesoporous carbon-based particles composed of multiple layers of FLGs (e.g., 5-15 layers) grow from the carbon-containing species, the simultaneous incorporation of metal elements or metal-based alloys occurs to form at least partially covalently bonded (as well as at least partially metallically or ionically bonded) carbon-metal composites, also referred to herein as "cobetic" particle structures. In some embodiments, "pristine" graphene (representing graphene with few or no defects) is provided to or produced in the described MW torch reactor, which is not oxidized or contains little, if any, oxygen (e.g., <1%). In some embodiments, the metals are themselves (in the resulting cobetic material) fixed to one another by metallic bonds, and the carbon is itself (predominantly) fixed to one another by covalent bonds (prevalently in graphene or some other organized carbon-based 2D or 3D structure, e.g., matrix or lattice). Composite carbon-metal structures may include covalent bonds between carbon and metal atoms that occur at the metal-carbon interface.

[0017] The disclosed microwave plasma-based reactor process provides a reaction and processing environment in which gas-solid reactions can be controlled under non-equilibrium conditions (non-equilibrium refers to a physical system that is not in thermodynamic equilibrium but can be described in terms of variables that represent an extrapolation of variables used to define systems in thermodynamic equilibrium. Non-equilibrium thermodynamics refers to transport processes and chemical reaction rates, and the initial melting of metal powders can be independently controlled by ionization potential and momentum in conjunction with thermal energy). After in situ nucleation, solid, substantially solid, or semi-solid carbon-based particles can exit the plasma torch and be deposited in a layer-by-layer manner onto a temperature-controlled substrate (such as a drum). The exiting particles can be thermally sprayed onto certain substrates and bonded onto or into the substrate. In some cases, rather than using a substrate, the exiting semi-solid particles are assembled to form one or more directionally organized freestanding self-supporting structures. Unlike standard plasma torches, which have flow, power, and configuration limitations for operation, the microwave plasma torch of the present disclosure is equipped with control mechanisms (e.g., flow control, power control, temperature control, etc.) to independently control one or more component material temperatures and gas-solid reaction chemistries to produce unique dense highly textured covalent carbon-metal structures with advantageously and surprisingly very high degrees of uniformity.

[0018] The covetic materials produced by the disclosed MW reactor techniques provide a variety of competitive advantages not otherwise available in current materials or products. One such advantage relates to the inherent scalability and versatility to formulate unique, physically and chemically stable, commodity metal carbon composites that exhibit predictable deformation (stress, strain, elasticity, or some other identifiable physical characteristic) in a variety of configurations and / or constructions, such as (but not limited to): (1) dense thin film implants, (2) coatings, (3) thick strip stock, and (4) powder particles that can be subsequently remelted and cast, and / or used to form industrial metal alloy components. Any of the above dense thin film MW reactor produced carbon-based metal composite implants, and / or coatings, and / or strip stock, and / or powder particles all exhibit improved physical, chemical, and electrical properties when compared to existing base metal alloy formulations.

[0019] overview The disclosure herein describes the integration of low-load nanofiller carbon-based materials, such as graphene, with metals. Graphene is known for its unique structural features, such as its high aspect ratio and "2D" planar structure. Graphene has a unique in-plane sp 2 Due to the C=C bonds (which give it a 2D planar shape), graphene has surprisingly favorable mechanical, physical, thermal and electrical properties. Therefore, graphene appears to act as an ideal reinforcement for metal matrix composites when compared to alternatives such as the microfiller polyacrylonitrile (PAN)-based carbon fibers. However, even at low graphene nanoplatelet contents (loadings), anisotropic 3D networks are formed, which results in significant improvements in thermal and electrical conductivity as well as mechanical properties.

[0020] Problems encountered when using carbon nanofillers in metal matrix composites include poor dispersion due to poor wetting (the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions when the two come into contact; the degree of wetting is called wettability, which is determined by the balance of forces between adhesive and cohesive forces). The increased surface area provided by nanofillers causes the particles to agglomerate and cluster, and twist due to van der Waals forces between the carbon atoms. Agglomeration and clustering of nanofillers in metal matrix composites can lead to the formation of undesirable cracks and pores that can ultimately compromise the structural integrity of the resulting material, leading to premature failure under high loads or conditions of use.

[0021] Although many processing approaches have been (and may still be) used to manufacture metal matrix composites, such as traditional powder metallurgy, hot rolling, casting, and additive manufacturing, achieving uniform dispersion of nanofillers remains problematic. Damage to nanofillers due to stresses applied during consolidation, and undesirable or uncontrollable chemical reactions with the matrix at high temperatures during sintering and casting are some of the problems faced in attempting to achieve dispersion of nanofillers.

[0022] The defect-free basal planes of graphene exhibit exceptionally favorable chemical stability compared to the sides and edges of the graphene sheets, which are more likely to interact with metals than the basal planes, resulting in carbide formation (thermodynamically favorable due to Gibbs free energy). However, during processing, defects can easily form on the basal planes, which can lead to carbide formation and adverse effects on composite properties. Therefore, relatively harsh processing conditions, such as high temperature and pressure, can adversely affect the quality of the interface between the carbon nanofillers and the metal-based matrix surrounding them. In particular, high temperature and pressure can adversely affect wetting, structural integrity, can have undesirable effects on carbide formation, and can cause other deleterious interfacial reactions.

[0023] Using an alternative process called Kobetic bodies (as introduced earlier), carbon nanofillers have been successfully incorporated into metal matrices. In the Kobetic-related process, a network of graphene "ribbons" and nanoparticles has been shown to form in liquid metals using an applied electric field, and this network exhibits exceptional stability within the metal matrix, even after remelting. Correspondingly, the composite structure conducts heat and electricity more efficiently than the parent metal.

[0024] Uniform dispersion Since one of the problems in incorporating graphene into a metal matrix has been to achieve uniform dispersion, cobetic body processing overcomes this problem through the concomitant exfoliation and wetting of the graphene ribbons and / or particles in an applied electric field (either from the carbon electrodes or from the destruction of the carbon additives). Impurities such as oxygen and hydrogen can be managed through redox reactions at the particle surface, which can promote wetting / dispersion, assuming the induced voltage at the surface is appropriate. The problem is one of controlling the structural integrity and uniformity (e.g., uniformity in terms of dimensions, defects, etc.) of the graphene ribbons and / or particles, as well as controlling the chemical reactivity with metals at high temperatures, and controlling the distribution of the particles in the bulk as well as at the melt surface.

[0025] More Complexity Although the primary mode of energy conduction (both thermal and electrical) in metals may be electrons (at least in part), and the degree of crystallinity and impurity of fillers such as graphene can control the thermal conductivity of metal-matrix composites (where conduction is via phonons in graphene), there must be either some registry and / or coherence (e.g., integrally bound nanoscale carbon) with the metal lattice (additionally or alternatively referred to as scaffold, matrix, or structure) or a minimum platelet spacing (e.g., proximity or network) that is critical for conduction between platelets (e.g., graphene would need to be a single layer or only a few layers, and tens of nanometers in length). However, for reinforcement of a metal matrix, graphene may need to be chemically bonded (or even physically bonded in some cases) to the matrix for adequate load transfer (note that graphene lengths can exceed about 0.5 μm for maximum load transfer). Solid solution strengthening relies on cohesive and / or semi-cohesive elastic strain between carbon (graphene) nanofillers and the metal lattice, but apart from this, discrete graphene nanoparticles can act as a barrier against dislocation piling up or pinning at grain boundaries (Hall-Petch grain refinement, etc., which represents a method of strengthening materials by modifying the average crystallite (grain) size. This method is based on the knowledge that grain boundaries are insurmountable boundaries for dislocations, and also on the knowledge that the number of dislocations within a grain affects how stresses build up in neighboring grains, which ultimately activates dislocation sources and thus allows dislocations in neighboring grains. Therefore, by modifying the grain size, it is possible to affect the number of dislocation piling up at grain boundaries, leading to strength), both of which improve mechanical properties.

[0026] Again, graphene, thanks to its 2D nature and large surface area, can orient along domains at grain boundaries in addition to aligning along slip planes within the metal structure. The greater the alignment and registry (at the atomic level) of the nanofillers with the surrounding metal matrix crystal structure, the greater the stability and enhancement of the properties of the metal matrix composite structure, whether the properties of interest are chemical, mechanical, thermal, or electrical.

[0027] Fundamentally, whether carbon grows on the metal surface (heterogeneous) or precipitates from the melt (homogenous) depends on the solubility of carbon in the metal (as shown in the binary phase diagram on the right side of Figure 10). The solubility of carbon in pure transition metals (and in general many pure metals) is very low, for example, near the melting point of the metal, but increases when the temperature is high enough above the melting point of the metal (e.g., above 2,000°C). The solubility of carbon in nickel, for example, is around 2.5% near the hypereutectic point, which is one of the higher solubilities of carbon in pure metals. Note that the addition of interstitial impurities, such as oxygen, boron, or nitrogen, or replacement atoms to the metal can affect (e.g., increase) the solubility of carbon. It has been shown that the higher the solubility of carbon in the metal or the higher the temperature of the molten metal, the thicker the carbon precipitates on the metal surface when the metal cools and solidifies. It is important to note that the solubility of carbon is higher near the free surface, which, combined with the interfacial energy of the liquid-air interface, favors the precipitation of solid carbon at the metal melt-air interface. Apparatus and techniques for operating said apparatus for overcoming the problems associated with this phenomenon are discussed in conjunction with the drawings and corresponding description.

[0028] Definitions and Use of Drawings For ease of reference, some of the terms used in this description are defined below. The terms and their individual definitions provided are not strictly limited to the definitions. Certain terms may be further defined by the way in which the term is used within this disclosure. The term "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" should not necessarily be construed as preferred or advantageous over other aspects or designs. Instead, the use of the word exemplary is intended to present concepts in a concrete manner. As used in this application and the appended claims, the term "or" is intended to mean inclusive "or" rather than exclusive "or". That is, unless otherwise stated or clear from the context, "X utilizes A or B" is intended to mean any of the natural all-inclusive variations. That is, if X utilizes A, X utilizes B, or X utilizes both A and B, then "X utilizes A or B" is satisfied in any of the above examples. As used herein, at least one of A or B means at least one of A, or at least one of B, or at least one of both A and B. In other words, the phrase is disjunctive. The articles "a" and "an" as used in this application and the appended claims should be construed generally to mean "one or more" unless otherwise indicated or the context clearly dictates a singular form.

[0029] Various embodiments are described herein with reference to the drawings. It should be noted that the drawings are not necessarily to scale, and that components of similar structure or function may be designated by like reference characters throughout the drawings. Also, the drawings are intended only to facilitate illustrating the disclosed embodiments. The disclosed embodiments are not intended to be exhaustive and representative of all possible embodiments, nor are they intended to impute any limitations with respect to the scope of the claims. Additionally, the illustrated embodiments do not necessarily depict all aspects or advantages of use in any particular environment.

[0030] An aspect or advantage described in conjunction with a particular embodiment is not necessarily limited to that embodiment and may be implemented in any other embodiment, even if not so described. References throughout this specification to "some embodiments" or "other embodiments" indicate that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. That is, the appearance of the phrase "in some embodiments" or "in other embodiments" in various places throughout this application does not necessarily refer to the same embodiment or embodiments. The disclosed embodiments are not intended to limit the scope of the claims.

[0031] Description of Example Embodiments FIG. 1A is a comparative diagram 1A00 illustrating two different Covetic material formation techniques 102 and respective example materials resulting from utilizing each.

[0032] In the case of conventional metal smelting methods 103 for producing covetic materials, solid carbon is added to molten metal. This conventional metal smelting technique is controlled by the kinetics of carbide formation and interdiffusion across the solid-liquid (e.g., carbon-metal) interface under an applied current, which provides additional energy to eliminate stacking fault energy between carbon and metal atoms. Thus, conventional metal smelting techniques for forming covetic fabrications are not significantly different from other composite processing methods such as powder metallurgy and / or hot rolling. Such composite processing involves consolidating second phase particles into a metal matrix. Such conventional composite processing methods face many problems associated with dispersion and / or distribution, reactivity, and variability in material properties. Furthermore, conventional covetic processing relies on batch processing, which often results in inconsistent conversion rates and wide variability in the resulting properties.

[0033] As depicted in agglomerate image 105, when using conventional metal fusion techniques 103, the resulting material suffers from severe carbon agglomeration, which results in (1) a limited role for carbon in reinforcing the lattice, and (2) limited tunability of the surface morphology for surface functionalization. In comparison, when using the techniques of the present disclosure, the resulting material exhibits near uniform homogeneity (e.g., no agglomerates), which arises from the uniform distribution of carbon in the lattice, as shown in homogeneity image 106.

[0034] Covetic materials, as depicted in the homogeneous image 106, can be characterized by many desirable material properties 108, such as uniformity, high carbon loading, low carbon content at the surface, etc. These properties are highly desirable and do not exhibit materials formed using conventional metal fusion methods 103. Therefore, what is sought is an improved approach that overcomes the shortcomings of conventional metal fusion methods 103.

[0035] One such improved approach involves a plasma spray torch process 104. Utilizing a plasma spray torch process provides a consistent yield of Covetic material, thereby overcoming the yield shortcomings of traditional metal fusion processes. Moreover, utilization of a plasma spray torch process provides Covetic material that retains the improved mechanical, thermal, and electrical properties described above, thereby overcoming the shortcomings of materials obtained by traditional metal fusion processes.

[0036] Improved approach As shown, the plasma spray torch process 104 can be configured to use the input material as introduced (showing the provision of a gaseous carbon-containing feedstock species such as methane and the addition of energy to the feedstock species by applying MW energy toward the methane gas or the like). However, at high temperatures, dissociation of the carbon-containing gas (such as methane or other hydrocarbon sources) can result in the growth of self-limiting monolayers of carbon, and more specifically, pristine graphene, on or in the metal (e.g., copper, gold, zinc, tin, and lead) lattices. The number of monolayers depends, at least in part, on the solubility of carbon in the metal. The growth kinetics, bonding, and final structure of the graphene film on the metal substrate depends on the valence electrons and symmetry (close-packed planes) of the metal. Similarly, when growing on carbon, metals can preferentially nucleate and grow on defect sites of the carbon, or selectively on oxygen- or hydrogen-terminated sites as well. Monolayers of alternating carbon and metal stacks are then formed to realize the improved properties of the graphene-reinforced metal composite structures.

[0037] Microwave plasma reactors allow for the continuous nucleation and growth of pristine 3D few-layer graphene particles from a hydrocarbon gas source. Select elements can also be added to the plasma gas stream to incorporate them into the 3D graphene particle scaffold. The microwave plasma reactor process provides a unique reaction environment in which gas-solid reactions can be controlled under non-equilibrium conditions (e.g., ionization potential and momentum can be combined with thermal energy to provide independent control of chemical reactions). Reactants can be introduced into the plasma reactor zone as solids, liquids, or gases to allow independent control of the nucleation and growth kinetics of unique non-equilibrium structures (e.g., graphene on metal and metal on graphene).

[0038] For example, to produce integrated graphene-metal composites at the nanometer scale, fine nanometer-scale metal particles can be introduced into a microwave plasma torch along with a hydrocarbon gas such as methane. The methane can dissociate into hydrogen and carbon (e.g., using ideal energy microwave plasma to form C and C2), which can then nucleate on the semi-molten surface of the metal particles to grow ordered graphene. A non-equilibrium energy state can be created by adjusting the process conditions to independently control the metal temperature with respect to the reactivity and delivery of carbon to the metal surface. Ionized hydrogen (or other ions) in a controlled low energy state can be used to act / sputter on the growing graphene and metal surfaces without damaging the structure of the graphene-metal composition. This then promotes further growth of the alternating graphene-metal layers. Also, depending on the residence time and energy in the plasma reaction zone, metal-graphene structures can be produced with specific properties that are retained even when the metal-graphene structures are rapidly cooled as they are sprayed onto a substrate at a controlled temperature. Metal-graphene structures are formed in a plasma with controlled energy as well as controlled temperature of the substrate, providing independent control of the energy conditions throughout the entire evolution of these cobetic materials.

[0039] Graphene can be applied (and / or deposited) onto metal or metal-containing layers of material by "sputtering" (a phenomenon in which microscopic particles of a solid material are expelled from its surface after the material itself is bombarded by energetic particles of a plasma or gas. The fact that sputtering can be made to affect extremely thin layers of material is frequently exploited in science and industry, where sputtering is used to perform precise etching, analytical techniques, and deposit thin film layers in the manufacture of optical coatings, semiconductor devices, nanotechnology products, and the like). When used with the MW plasma reactor of the present disclosure, such sputtering can be controlled, as described, by controlling the residence time and energy within the plasma reaction zone to promote the growth of alternating graphene metal layers. These alternating graphene metal layers are organized in coherent planes of atoms in regular (e.g., crystallographic) arrangements. This crystallographic arrangement is retained when the graphene metal layer is rapid quenched (in materials science, quenching, or rapid / fast quenching, refers to the controlled rapid cooling of a workpiece in water, oil, or air to obtain certain material properties. Quenching, a type of heat treatment, prevents or controls unwanted low-temperature processes, such as phase transformations, from occurring by narrowing the time window during which unwanted reactions are thermodynamically favored and kinetically accessible. For example, quenching can reduce the grain size and increase the hardness of both metallic and plastic materials) onto a cooler substrate. Rapid quenching, as described, serves to essentially "freeze" (not merely the traditional definition of a liquid to solid phase change, but rather to maintain a substantially solid state) the graphene in the desired crystallographic arrangement formed in the plasma reactor relative to the metal. The homogeneity within and on the resulting material is extremely uniform. This extremely uniform homogeneity can be used to distinguish materials formed using metal melting methods 104. This is because the metal fusion process 104 does not allow for control of the ion energy independently of the thermal energy.More specifically, because the metal fusion process 104 cannot achieve as high an ion energy as desired independent of thermal energy, the temperature of the metal fusion reaction chamber may become too high for the graphene metal layer to organize into coherent planes of atoms in the desired crystallographic arrangement.

[0040] Thus, when using metal fusion method 104, the desired crystallographic arrangement of the graphene metal never occurs, and therefore may not be retained even when the graphene metal layer is quenched onto a cooler substrate. Instead, when using metal fusion method 104, unwanted carbon precipitation occurs (e.g., carbon precipitates out of the melt), which then leads to unwanted agglomerates, which then lead to inhomogeneity in the product. This inhomogeneity in the product may result in less than ideal chemical and / or physical (mechanical) characteristics of the resulting material, which may lead to, for example, but not limited to, premature mechanical failure.

[0041] Figure 1B presents a high-resolution transmission electron microscope image 114 and a high-resolution energy dispersive X-ray analysis image 116. The homogeneity image 106 of Figure 1A is also shown here for convenience.

[0042] As depicted in this example set of images, carbon is distributed uniformly throughout the metal lattice. This is highlighted in the high-resolution transmission electron microscope image 114. Moreover, the extremely high carbon loading in the metal lattice is evident in the high-resolution energy dispersive X-ray analysis image 116. In this example, the carbon loading is approximately 60% of the total copper carbon lattice. This is shown in the high-resolution energy dispersive X-ray analysis image 116. In this particular image, the dark areas are carbon and the light areas (appearing as dots) are copper.

[0043] As can be seen from the images, and specifically from the pattern of the high resolution energy dispersive X-ray image 116, the carbon and base metal (e.g., copper in this case) are uniformly distributed. This uniform lattice level distribution is present at the surface as shown, and also at depth in the base metal. Additional images of the Covetic material are shown in Figures 20A1, 20A2, and 20B after discussing (1) the material evolution process, (2) the plasma spray torch apparatus, and (3) various configurations of the plasma spray torch.

[0044] In one use scenario, the Covetic material of FIG. 1B can be manufactured using an adjustable microwave plasma torch that produces integrated graphene-metal composite films at high speed and in large quantities. One particular manufacturing process in which graphene is grown on small molten metal particles will now be briefly described.

[0045] 2 depicts a manufacturing process 200 for growing graphene on small molten particles. Optionally, one or more variations of the manufacturing process 200, or any aspect thereof, can be practiced in the context of the structures or functionality of the embodiments described herein. The manufacturing process 200, or any aspect thereof, can be practiced in any environment.

[0046] One possible method is to use a "non-equilibrium energy" microwave plasma torch to provide non-equilibrium control of the temperature of the metal independent of carbon generation. This plasma torch energy is then directed at the molten and / or semi-molten metal particle surface. This technique allows time for growth to occur in the melt. Growth in the melt (or semi-molten or core-shell material) generated in the torch will flow through the main plasma plume to the metal surface where it will grow, and then be rapidly quenched. This technique provides a means to grow thick films that can be layered to grow into homogenous thick ingots and / or grown in or on component parts that are later machined or remelted for use.

[0047] Also, Figure 2 is presented to illustrate the effect of independent control of component temperature and gas-solid reaction chemistry when growing graphene on small molten particles. Figure 2 shows the progression through multiple processes of Covetic material production and presents the process used in the formation of Covetic material utilizing a plasma torch.

[0048] As shown, the semi-solid particles emerging from the plasma torch can be deposited in a layer-by-layer fashion onto a temperature-controlled substrate. Unlike standard plasma torches, which have limited operable flows as well as control over power and other configurations, the microwave plasma torches discussed herein can be operated to provide independent control over component material temperatures as well as gas-solid reaction chemistry.

[0049] As can be seen from the above disclosure, microwave plasma sources can provide (by way of example): (1) higher plasma density, (2) ion energies with narrower ion energy distributions, and (3) improved coating properties. This is due, at least in part, to improved power coupling and (electromagnetic energy) absorption at 2.45 GHz. Depending on pressure, typical electron temperatures are on the order of 1 eV to 15 eV, with >10 11 cm -3This results in a plasma density of 1000 nm. Such a low electron temperature is not only advantageous for controlling the plasma chemistry, but also for limiting the ion energy for the argon-based coaxial microwave plasma. The ion energy for the argon-based coaxial microwave plasma is typically in the range of 5 eV to 80 eV. As a result of the narrow plasma sheath formed using such a high density plasma, collisional broadening of the ion energy distribution is prevented, resulting in a sharper ion energy distribution, which aids in precise control of certain film deposition processes. Pulsed power can also be utilized for microwave plasma to create and control non-equilibrium energy. During application of microwave energy, power is delivered throughout the volume in which the plasma is to be formed, and thus energy is accumulated in a stepwise collisional energy type.

[0050] The above discussion of FIG. 2 includes techniques for applying microwave energy power, which are disclosed in more detail below.

[0051] FIG. 3 shows a plasma energy diagram 300 illustrating how a pulsed microwave energy source can be used to grow graphene on small molten particles.

[0052] Microwave plasma sources have the potential to achieve higher plasma densities, narrower ion energy distributions, and improved coating properties as a result of improved power coupling and absorption at 2.45 GHz. Depending on the pressure, typical electron temperatures are on the order of 1 eV to 15 eV, with >10 11 cm -3This results in a plasma density of 1000 nm. Such a low electron temperature is not only advantageous for controlling the plasma chemistry, but also for limiting the ion energy for argon-based coaxial microwave plasma, which is typically in the range of 5 eV to 80 eV. As a result of the narrow plasma sheath formed using such a high density plasma, collision broadening of the ion energy distribution is prevented, resulting in a sharp ion energy distribution, which is necessary for precise control of some film deposition processes. Also, through the use of pulsed power for the power delivered to the microwave reactor, plasma non-equilibrium energy can be formed and controlled. During application of microwave energy, power is delivered to the entire volume in which the plasma is to be formed, and thus energy is accumulated in a stepwise collision energy type.

[0053] Once the initial plasma is formed in most of the volume, the energy is greatest at the delivery antenna and continues to increase in a very localized manner. The nearby plasma density decreases slightly until the plasma contracts. Further details regarding the general approach to making and using pulsed microwave energy sources are described in U.S. Patent Publication No. 10,332,726, published June 25, 2019, which is hereby incorporated by reference in its entirety.

[0054] 3 shows that the initial energy of the plasma is very high in the non-equilibrium state before dropping significantly at the stable temperature. More specifically, the plasma energy phase diagram depicts the transition from an initial high energy non-equilibrium state to a lower energy stable equilibrium state. When the initial plasma is formed, the energy is greatest at the delivery antenna and continues to increase in a very localized manner until the plasma contracts and is lost to the remainder of the chamber due to energy shielding.

[0055] The pulsed microwave energy source can be controlled to optimize the electron temperature to grow graphene on small molten particles. This is particularly effective when the pressure is >>20 Torr. The chamber environment must be controlled to ensure that the chemical dissociation by the plasma is homogenous, and that the coating of material is also homogenous.

[0056] As shown in FIG. 3, the energy profile shows that the initial energy is high, then drops to a lower level and remains at that level until the power is removed. The plasma goes through this energy cycle again after it is extinguished and restarted. By reducing the time between the initial plasma ignition and the point at which the plasma stabilizes, the plasma can remain primarily in the bulk of the system, resulting in a more homogenous dissociation of materials in the bulk of the system. Reducing the time between the initial plasma ignition and the point at which the plasma stabilizes can be achieved by controlling the frequency and duty cycle of the pulses.

[0057] One technique for controlling electron temperature in a pulsed microwave reactor is shown and described in connection with FIG.

[0058] 4 depicts an electronic temperature control technique 400 used to grow graphene on small molten particles. Optionally, one or more variations of the electronic temperature control technique 400 or any aspect thereof can be implemented in the context of the construction or functionality of the embodiments described herein. The electronic temperature control technique 400 or any aspect thereof can be implemented in any environment.

[0059] 4 illustrates an embodiment for growing few-layer graphene on molten nanoscale particles rather than mixing carbon into the bulk of the molten slurry. Specifically, the figure is presented in relation to the contribution of this technique to controlling plasma temperature through control of microwave pulse frequency.

[0060] Control of plasma temperature via control of pulse frequency As depicted in Figure 3 above, the energy profile shows that the initial energy is high, then throttles back to a lower level and remains at that level until power is removed. The plasma goes through this energy cycle again after it is extinguished and restarted. By reducing the time between the initial plasma ignition and stabilization, the plasma is able to remain primarily in the bulk of the system, resulting in a more homogenous dissociation of materials in the bulk of the system.

[0061] This effect is substantially dependent on the timing of the on / off cycle of the microwave energy source, as shown in Figure 4. By controlling the pulse frequency, optimal chemical dissociation and uniform coating can be achieved. Furthermore, by setting the pulse frequency, the average temperature of the plasma can be controlled as well.

[0062] Plasma temperature control in a microwave plasma torch. The integrated microwave plasma torch discussed herein is used to address the formation of integrated, second phase carbon-metal composite structures with improved mechanical, thermal and electronic properties over existing metal alloys and conventional composite processing methods. Moreover, the microwave plasma torch can be used to form carbon-metal composite coatings and particles directly on high value asset components. Moreover, the method and equipment meet many clean energy goals related to improved power distribution and efficient transformers and heat exchanger performance.

[0063] Practical applications of microwave plasma torches. With integrated microwave plasma torch technology, materials can be deposited and / or formed at high speeds and economically (e.g., cost-effectively) and can be applied in a wide variety of configurations. Beneficiaries of this technology include various energy production industries, especially those related to power transmission and storage, the transportation industry, the military equipment industry, and many other manufacturing industries. In one specific practical application, the metal surfaces of airplanes can be treated by plasma spraying to create a covetic material at the metal-air interface. In this way, the metal surface is less susceptible to corrosion. Also, the carbon atoms near the surface allow other materials to chemically bond with the carbon atoms and / or to attach to the surface. The other materials capable of chemically bonding with the carbon atoms can be selected based on the requirements arising in various practical applications.

[0064] As another specific practical application, metal surfaces of airborne vehicles (e.g., airplanes, helicopters, drones, projectiles, missiles, etc.) can be treated by plasma spraying to produce a Covetic material coating that acts as an infrared obscurant (e.g., as a countermeasure to detection).

[0065] 5 illustrates a twin plasma torch apparatus 500 used to grow graphene on small molten particles. Optionally, one or more variations of the twin plasma torch apparatus 500 or any aspect thereof can be implemented in the context of the construction or functionality of the embodiments described herein. The twin plasma torch apparatus 500 or any aspect thereof can be implemented in any environment.

[0066] The equipment setup shown uses: (1) a metal plasma spray torch to spray molten metal onto the surface of a heated substrate (Al, Cu, Ag, etc.), and (2) a microwave plasma torch to deliver ionized carbon and plasma radicals to the molten surface to induce the growth of cobatic bodies on the molten metal.

[0067] The system is inserted into an inert gas environment or into an atmospherically controlled chamber to provide better control of the oxidation of the material. In one embodiment, the settings and operation of the torch in Figure 5 are as shown in Table 1, the details of which are discussed below. [Table 1]

[0068] Step D1: Identification and Selection of Reactant Materials Any number of metals can be simultaneously plasma sprayed together with metastable carbon species to form nano carbon metal composite structures. Different metals with high electrical and thermal conductivity can be used when forming 2D graphene at concentrations above their thermodynamic solubility limits. In some cases, two different metals are selected, each with a different carbon solubility limit and / or different melting point and / or different density and / or different crystal structure.

[0069] Step D2: Selection, modification, and validation of microwave plasma torches and "standard" plasma spray torches The apparatus of Figure 5 can be substantially comprised of a "standard" off-the-shelf plasma spray torch and a microwave plasma torch (in one particular embodiment). Having two torches allows for two different processing steps: (1) initial melting of the metal, and (2) nucleation / growth of graphene platelets from a hydrocarbon source. Each of the two torches can be controlled independently of the other.

[0070] As shown in FIG. 5, the two torches are arranged for simultaneous or sequential operation. Specifically, a microwave plasma with low electron temperature and high electron density can be used to optimize graphene formation (including nucleation rate at the carbon supersaturation limit), while a standard plasma spray torch can be used to heat metal powder / particles to a molten or semi-molten state and then accelerate the particles (along with the nucleated ionized carbon / graphene) toward the substrate. The two independent flows can be coordinated to achieve fine-scale graphene growth on the semi-molten particle surface. In some cases, the dual torch configuration includes a means to maintain an inert atmosphere (e.g., cover gas) at or near the torch exit flow and at or around the impact region on the surface of the substrate. This is because contaminants from the ambient air (e.g., oxygen, nitrogen, and moisture) can affect the bonding between carbon and metal atoms. Thus, in certain embodiments, the dual torch system is configured to be inserted into a fully controlled inert gas environment (e.g., a chamber) to provide effective control of material oxidation.

[0071] Step D3: Rationale and definition of plasma processing parameters The reactants (e.g., hydrocarbons) and inert gases and flows are selected to ensure the stability of the plasma and to ensure control of the nucleation and growth processes within the plasma (e.g., supersaturation limits and flow rates for a given gas mixture). The acceleration and temperature of the metastable carbon are controlled during its motion from the plasma to the substrate. The process conditions of a standard plasma spray torch are set accordingly to produce a consolidated thin film with which the carbon can collide and react. The surface temperature and local gas phase environment are controlled to promote interaction and growth of the metastable carbon phase.

[0072] Step D4: Operation of a dual (metal and microwave) plasma torch Various parameters of both the metal and microwave plasma torch process windows are configured to be controlled independently or, in some embodiments, controlled in conjunction with each other. Before, during, or after operation of one or more of the metal and microwave plasma torch (referred to herein as "dual plasma torch"), the integrated carbon metal formation process window is characterized. Moreover, one or more parameters or combinations of parameters are selected, the deposition of carbon metal is observed, and the as-deposited sample can be characterized for various differences using any technique known in the art, including (but not limited to): morphology (e.g., using a scanning electron microscope (SEM)), structure (e.g., by X-ray diffraction (XRD) and by Raman spectroscopy), and / or physical and chemical composition.

[0073] 6 illustrates a pulsed microwave plasma spray torch apparatus 600 that can be adjusted to grow graphene on small molten particles. By way of example, one or more variations of the pulsed microwave plasma spray torch apparatus 600 (or any aspect thereof) can be implemented in the context of the construction or functionality of the embodiments described herein. The pulsed microwave plasma spray torch apparatus 600 (or any aspect thereof) can be implemented in any environment.

[0074] In this configuration, transverse electric (TE) microwave power means can be coupled on (or in some embodiments, substantially through) the central dielectric tube to propagate microwave energy therein throughout the central dielectric tube. The gas (in this example) supplied to the central region can be a hydrocarbon gas such as methane that absorbs microwave radiation. Metal powder is supplied (carried by a substantially inert carrier gas) and heated in the body (or main chamber) of the pulsed microwave plasma spray torch device 600 by a combination of plasma-derived energy and supplied thermal energy. When exposed to such energy, the metal powder reaches its melting point and melts, producing a viscous, flowable liquid material, or droplets (which may contain semi-solid materials), or any other possible dispersion (highly dependent on the associated melting conditions).

[0075] As the hydrocarbon gas decomposes into its constituent elemental species, carbon radicals nucleate on the exposed surfaces of the molten metal droplets. A combination of microwave energy adjustment settings and thermal plume temperature settings allows for different temperatures in the central region of the pulsed microwave plasma spray torch device 600 between the melting temperature and the plasma decomposition / ionization temperature. The non-equilibrium conditions (indicating temperature, heat, etc.) in the central chamber or region of the plasma spray torch device allow (or in any way encourage) the graphene / carbon to take up space within the lattice (indicating that the synthesized lattice structure of the carbon material, along with any input metal(s), positions the individual carbon and metal atoms such that they can at least partially align), while the rapid quench creates conditions conducive to the growth of cobetic material. Diagrams showing the internal lattices in which the carbon and metal lattices are oriented such that the carbon and metal atoms are at least partially aligned are presented in Figures 8A-8B, 12, 26C, and 26D, and in the corresponding textual descriptions below.

[0076] The single integrated microwave plasma torch of Figure 6 can be set up and operated as depicted in Table 2 below, the details of which are described below. [Table 2]

[0077] Step S1: Deploy a single integrated microwave plasma torch Figure 6 depicts a single integrated microwave plasma torch. The torch has the ability to process solid, liquid, and vapor reactant species using small amounts of inert gas or differential pumping vacuum (for example) to control gas flow. The torch can be deployed in any environment (such as a laboratory, research facility, or large industrial company).

[0078] Step S2: Operate a single integrated microwave plasma torch to form a graphene-doped metal composite ("Cobetic") alloy. Microwave energy is delivered in a collinear waveguide arrangement with a centralized gas supply system for efficient microwave energy absorption. A microwave energy source is used to heat the metal to a semi-molten state. As CH4 (or other hydrocarbon source) is decomposed (becoming its constituent species) in the exhaust plume directed into the surface wave plasma gas dissociator, carbon radicals can nucleate (e.g., in an organized layer-by-layer manner) on the surface of the metal droplets via excitation by plasma radicals (directed at the metal droplets). Microwave thermal plume temperature and plasma energy modulation allow independent temperature control between melting and plasma decomposition / ionization occurring within the central region of the pulsed microwave plasma spray torch apparatus 600.

[0079] Process conditions are measured and optimized. The desired process conditions are controlled by or for the integrated microwave plasma torch to form the graphene-loaded metal composite directly in the single or multi-stage plasma reaction torch. The plasma torch can be modulated in different regions of the surface wave plasma to improve the resonance (modulation) time and optimize the formation of the desired metal carbon structure.

[0080] In addition to the process gas ports shown in the depicted locations (e.g., for the introduction of a hydrocarbon process gas 605), additional ports 604 can be provided at different locations. Such additional ports can be used to control how the process gas is introduced into the microwave field and to introduce other process gases. By way of example, the process gas can be SiH4 or NH3. In some embodiments, there can be multiple inputs for gases or multiple inputs for particles (e.g., one for carbon and one for metals), and the input locations can be positioned at different zones of the plasma torch.

[0081] The above settings and conditions, as well as others, are optimized to provide conditions on the substrate surface that allow the impinging particles to consolidate into a coating. The as-deposited coating is analyzed and characterized according to the methods outlined in step S3 below.

[0082] Step S3: Verify / characterize graphene (secondary phase) metal particles Characterization of the as-deposited integrated carbon-metal composite structures is accomplished using multiple techniques. For example, X-ray photoelectron spectroscopy (XPS) and / or SEM-EDS can be used to determine chemical composition, bond energy (nanoscale carbon detection), and distribution. Similarly, energy dispersive X-ray spectroscopy (EDS) and / or SEM and / or Raman spectroscopy and / or XRD can be used to determine morphology and / or measure particle size and structural aspects. The electrical and thermal properties, as well as tensile strength and elasticity of the composites can be evaluated using any known technique.

[0083] result The technique uses a microwave plasma torch to continuously manufacture metal matrix composites. The process involves the formation of a nucleation and growth zone of material within the plasma, followed by an acceleration and impact zone to consolidate the material on the substrate. Each zone offers unique control of the synthesis / formulation and integration of different materials. The selective and unique formation of alloy particles within the plasma, which then allows for unique additive processes to control consolidation parameters such as porosity, defect density, residual stresses, chemical and thermal gradients, phase transformations, and anisotropy through control of momentum (mainly velocity) and thermal energy during impact on the substrate.

[0084] A variety of materials are selected for use across a wide range of growth kinetics within the plasma operating environment. In particular, different hydrocarbon gas sources with specific ratios of carbon to oxygen and hydrogen, as well as solid metal (or metal alloy) particle sources with different carbon solubilities, melting points, and crystal structures can be processed through a pulsed energy plasma torch processing system. Thus, specific plasma processing parameters can be identified for the initial surface melting of the particles with accompanying nucleation / growth and incorporation of 2D graphene and resputtered metal on the metal surface.

[0085] When graphene is incorporated into metals from a microwave plasma torch, the as-deposited material / film is characterized for "covetic-like" properties. By way of example, such covetic-like properties can be characterized for (for example): (1) chemical composition (e.g., for detection of impurities or for detection of carbon form), (2) carbon distribution (e.g., interstitial, which indicates the location of carbon atoms or species within a metal matrix or lattice, either intragranular or intergranular), (3) electrical conductivity, and (4) mechanical strength of the material. Characterization may include contrast between graphene-added and unalloyed base metal. Additionally, and strictly by way of example, as-deposited materials using a microwave plasma torch may exhibit carbon-to-metal ratios throughout the range of about 3% to 90%, inclusive. In some circumstances, the carbon-to-metal ratios may range throughout the range of about 10% to about 40%, inclusive. In some circumstances, the carbon-to-metal ratios may range throughout the range of about 40% to about 80%, inclusive. In some circumstances, the carbon to metal ratio ranges from about 80% to about 90%, inclusive. In some circumstances, the carbon to metal ratio is greater than 90%, inclusive. The carbon to metal ratio can be influenced (or further influenced) by parameters or specifications that govern the coating process (e.g., temperature, thickness, uniformity, etc.).

[0086] FIG. 7 is a diagram 700 depicting a coating process. The diagram shows a metal substrate that is subjected to plasma torch spraying of a covetic material resulting in a composite carbon coating. The metal substrate may include any one or more of copper, aluminum, or other bulk metal materials. The covetic material may include one or more of carbon, graphene, nano-onions, carbon nanotubes (CNTs), carbide-infused materials, and the like.

[0087] Plasma torch spraying serves to coat an input material with a deposition material and can be operated using pulsed energy. As shown, the material deposited (e.g., by sputtering layer by layer) can be any one or more of carbon, metal (e.g., Al, Cu, Ti, Ta, etc.), and / or oxides or nitrides.

[0088] Several advantages emerge from the use of the torch. Among them is the scalability and versatility of the process to compound unique stable metal carbon composites into various configurations / constructions. These configurations / constructions range from fully dense thin film coatings to thick strips or particles that are then remelted and cast / formed into engineered metal alloy components. Each of the species across the range exhibits unexpectedly favorable (and desirable) enhanced mechanical, thermal, and electrical properties when compared to existing base metal alloy formulations. Also, the tunability of the concentration and distribution of covalently bonded 2D graphene in a metal alloy matrix beyond the thermodynamic solubility limit, as well as the formation of layers in a non-equilibrium environment, enables a new class of composite materials that can be engineered to meet specific applications and / or specific property requirements. Moreover, this can be done at a significantly reduced manufacturing cost when compared to other techniques.

[0089] The improved mechanical, thermal, and electrical properties can be applied to the majority of applications using copper and aluminum alloys. By way of example, such applications include (but are not limited to): electrical conductors and high voltage power cables, microelectronic thermal management and heat exchangers, and many applications using thin film electrical conductors, such as batteries, fuel cells, and photovoltaics. In particular, the combination of microwave plasma torch processes and feasible carbon metal alloy production will result in significant energy savings in manufacturing, while providing increased thermal efficiency and reduced electrical losses in end-use performance.

[0090] The above plasma spray techniques depict only one category of methods for making Covetic materials. Another category involves spraying carbon particles onto small particles of molten metal. Such categories and the various chemical species included therein are shown and discussed with respect to Figures 8A-8B, 9, 10, 11, 12, 13, and 14, and in the description of the figures herein.

[0091] 8A-8B are schematic diagrams depicting a plasma spray process 800 used to spray carbon particles onto small molten particles. Optionally, one or more variations of the plasma spray process 800 (or any aspect thereof) can be practiced in the context of the construction or functionality of the implementations described herein. The plasma spray process 800 or any aspect thereof can be practiced in any environment.

[0092] The plasma spraying technique of the figure is used in various coating processes where heated material is sprayed onto a surface. The feedstock (e.g., coating precursor) is heated by electrical means (e.g., plasma or arc) and / or chemical means (e.g., combustion flame). Using such plasma spraying techniques, coatings having thicknesses ranging from about 20 μm to about 3 mm can be provided, depending on the process and feedstock. Coatings can be applied over a wide range at high deposition rates. Using the above techniques, deposition rates are much higher than those achievable by conventional coating processes, such as electroplating or physical and chemical vapor deposition.

[0093] In addition to (or instead of) the above exemplary materials, types of coating materials that can be used for plasma spraying include metals, alloys, ceramics, plastics, and composites. These materials are fed to the spray torch in powder form or in wire form, then heated to a molten or semi-molten state and accelerated towards the substrate in the form of micrometer-sized particles. Combustion or electric arc discharge can be used as the energy source for plasma spraying. The resulting coating is made up of multiple layers of sprayed particles. In many applications, the surface of the substrate is not significantly heated, thus facilitating the coating of many materials, including the most flammable ones.

[0094] FIG. 9 is a scanning electron microscope image 900 showing the effect of spraying carbon particles (e.g., 20 nm to 40 microns in size) onto small molten metal particles. Carbon particles sprayed onto small molten metal particles can be used in a variety of specialized applications. For example, plasma aluminum graphite composites may be specifically designed to provide turbine engine coatings. Alternative examples include the use of aluminum and titanium alloys. The growth rate of this plasma spray coating material is parabolic. The plasma spray coating material deposits in a short time and this deposition is largely independent of temperature. To prepare the material surface, certain processes include preheating the material. In some embodiments, grit blasting is also performed to prepare the material surface. In some embodiments, some of the particles sprayed onto the surface form a covetic bond with the surface of the substrate while still hot enough. In other cases, the small molten particles are at a temperature to form a metal-metal bond.

[0095] Use of the microwave plasma torch techniques of the present disclosure allows for the production of improved materials when compared to the use of conventional torches. Specifically, the power control limitations and other design constraints inherent in conventional plasma torches limit their ability to independently control the input materials and other conditions necessary to produce carbon that is effective in producing covetic materials exhibiting significantly higher quality and uniformity.

[0096] FIG. 10 shows a diagram depicting a graphene growth temperature profile 1000 and a binary phase diagram. Optionally, one or more variations of the graphene growth temperature profile 1000 or any aspect thereof can be implemented in the context of the construction or functionality of the embodiments described herein. The graphene growth temperature profile 1000 or any aspect thereof can be implemented in any environment. The diagram also shows a binary phase diagram, in which the X-axis displays the carbon concentration in atomic percent in a selected metal (e.g., copper, as shown). The temperature of the temperature profile in the diagram is also shown in the phase diagram. A variety of metals can be used (e.g., silver, tin, etc.). In some cases, alloys are formed.

[0097] The concept behind the growth of single layer graphene (SLG) or few layer graphene (FLG) on molten metal is to dissolve carbon atoms in a transition metal melt at a certain temperature and then precipitate the molten carbon at a lower temperature (referring to creating a solid from a solution).

[0098] The schematic diagram depicts graphene growth from molten nickel by (for example): (1) melting nickel in contact with graphite (as a carbon source), (2) dissolving carbon in the molten liquid at high temperature, and (3) lowering the temperature to grow graphene.

[0099] As shown, maintaining the molten liquid in contact with the carbon source at a given temperature will result in dissolution of carbon atoms into the molten liquid and saturation of carbon atoms in the molten liquid due to the binary metal-carbon phase transition. Reducing the temperature will decrease the solubility of carbon in the molten metal and excess carbon will precipitate on the top of the molten liquid.

[0100] FIG. 11 is a cross-sectional view of a (conventional) plasma flame apparatus 1100. This figure is presented to distinguish the use of past plasma flame apparatus as a comparison with the use of microwave plasma torches of the present disclosure. Specifically, while the use of past plasma flame apparatus can produce diamond or diamond-like materials on metal surfaces, the process requires significant time to melt and diffuse the carbon material so that the final material is deposited on the metal surface. During the production of metal carbon composite materials as disclosed herein using embodiments of the present disclosure, it is desirable for graphene to grow and be fixed interstitially between layers (or within lattice or matrix sites) of the metal or metal-containing composite material. However, to do so, the temperature must be adjusted at a high rate. Unfortunately, past plasma torches do not provide substantial control of temperature and other conditions (as would be desirable in connection with achieving cobetic materials as desired herein) required to reduce the dimensions of the interstitial carbon structures to the nanometer scale.

[0101] In contrast, a pulsed microwave reactor (as related to the embodiments of the present disclosure as introduced above) and corresponding process is shown and described in FIG. 12, providing sufficient detail for the control of temperature and other conditions required to reduce the dimensions of interstitial carbon structures to the nanometer scale.

[0102] 12 depicts a pulsed microwave process flow 1200 used in "growing" graphene, where "growing" refers to the ordered deposition or application of graphene layer by layer onto a substantially flat exposed surface of a molten metal particle. Optionally, one or more variations of the pulsed microwave process flow 1200, or any aspect thereof, can be implemented in the context of the construction or functionality of the embodiments described herein. The pulsed microwave process flow 1200, or any aspect thereof, can be implemented in any environment.

[0103] When using the pulsed microwave process flow 1200 shown, graphene is grown on the small molten particles. This is accomplished by interactions that occur around the inlet 1204 in the pulsed microwave reactor (e.g., where the metal powder and carrier gas enter the reactor chamber). In addition to the inlet 1204, process gas ports 1202 and additional ports (e.g., additional ports 12031 and additional ports 12032) are provided at different heights on the side of the reactor apparatus. The waveguide traverses at least the distance from the location of the process gas port 1202 on the side of the reactor to the location of the inlet 1204 on the side of the reactor. Details of how to create and use ports to introduce and continuously feed materials into such a reactor for growing graphene on the small molten particles are disclosed further below. More specifically, certain components of the reactor of FIG. 12 are shown and described in relation to FIG. 13.

[0104] 13 is a perspective view of a conventional pulsed microwave plasma sprayed waveguide apparatus 1300 used to grow graphene on small molten particles. Optionally, one or more variations of the pulsed microwave plasma sprayed waveguide apparatus 1300 or any aspect thereof can be implemented in the context of the construction or functionality of the embodiments described herein. The pulsed microwave plasma sprayed waveguide apparatus 1300 or any aspect thereof can be implemented in any environment.

[0105] In this embodiment, the microwave delivery components and pulsed power supply are integrated to form a "surfaguide" (or similar) gas reactor. As shown, the combination of these components is configured to promote the growth of graphene on small molten particles using a microwave plasma torch.

[0106] An alternative approach is to perform microwelding using a tungsten inert gas (TIG) plasma source to partially or completely melt the metal. Such a microwelding technique is shown and described in connection with FIG.

[0107] 14 is a schematic diagram of a microwelding technique 1400 used to grow graphene on small molten particles. Optionally, one or more variations of the microwelding technique 1400 or any aspect thereof can be practiced in the context of the construction or functionality of the embodiments described herein. The microwelding technique 1400 or any aspect thereof can be practiced in any environment.

[0108] A low power, low flow TIG welder power supply and a controller with custom plasma containment can be effectively used to heat all types of metal particles. As shown, the exhaust plume, when introduced into the surface wave plasma gas dissociation tube, keeps the temperature high enough for graphene growth. This growth regime, including control of plasma radicals formed under non-equilibrium conditions and composed of hydrocarbons and other additive gases, offers many tuning opportunities available with microwave plasma spray equipment of various configurations. Figures 15, 18A, 18B, 18C, and 18D, as well as other figures and corresponding text, disclose exemplary configurations of plasma spray equipment.

[0109] 15 is a schematic diagram of a plasma spray apparatus in a coaxial configuration 1500. Optionally, one or more variations of the coaxial configuration 1500 or any aspect thereof can be implemented in the context of the construction or functionality of the embodiments described herein. The coaxial configuration 1500 or any aspect thereof can be implemented in any environment.

[0110] In a coaxial embodiment, microwave energy delivery is accomplished via TEM waves fed into an antenna, the outer portion of which is a quartz tube, around which powdered metal particles flow. The gas fed into the central region in this example is a hydrocarbon gas, such as methane, which absorbs microwave radiation. The powder is heated by microwave energy leaking from the central region and by external inductive heating, which causes the metal powder (in particle form) to melt near the inclined portion or top of the reaction chamber, as indicated. As CH4 decomposes (to its constituent species, carbon, hydrogen, and / or their derivatives), carbon radicals nucleate at the surface of the molten metal droplets through the energy of the plasma radicals. Adjusting the microwave duty cycle, as well as adjusting the inductive heating, as well as adjusting the plasma characteristics, helps maintain the temperature difference between the melting and plasma decomposition / ionization regions. Moreover, the non-equilibrium temperature allows (encourages) the graphene / carbon inter-lattice arrangement, and the rapid quench creates conditions conducive to further growth of the cobetic material.

[0111] 16 is a schematic diagram of a plasma spray apparatus 1600 illustrating the evolution of a material by processing it through a series of non-equilibrium energy states. Optionally, one or more variations of the plasma spray apparatus 1600 (or any aspect thereof) can be implemented in the context of the construction or functionality of the embodiments described herein. The plasma spray apparatus 1600 or any aspect thereof can be implemented in any environment.

[0112] The diagram depicts the evolution of the material as it passes through the device. Specifically, the diagram depicts a region near the tip where a different change in evolution occurs, as graphene grows on small particles of the metal melt. The material is then deposited on a substrate.

[0113] 17 depicts a surface wave plasma system 1700 for growing graphene on molten particles. Optionally, one or more variations of the surface wave plasma system 1700 or any aspect thereof can be implemented in the context of the construction or functionality of the embodiments described herein. The surface wave plasma system 1700 or any aspect thereof can be implemented in any environment.

[0114] In the configuration shown, a feed gas is fed into the central region of the apparatus. In this example, a hydrocarbon gas such as methane is used. The hydrocarbon gas absorbs microwave radiation, which provides a heat source that heats the metal powder. Thus, the metal powder is heated from both: (1) microwave energy leaking from the central region, and (2) external induction heating to melt the powder into a molten liquid near the tip. As the hydrocarbon gas decomposes, carbon radicals nucleate on the surface of the molten metal droplet via the energy of the plasma radicals.

[0115] FIG. 18A1 depicts an axial electric field configuration 1810 of a plasma spray torch. The formation of the Covetic material has been explored using several different apparatuses and corresponding processes. Any of the above apparatuses and corresponding processes can be adjusted to achieve the specific conditions for the formation of the Covetic material. In the specific axial electric field configuration of the figure, the process involves forming an electric field 1804 between electrodes to create a current through the melt of metallic and carbon materials. Specifically, as shown, a specially configured plasma torch has an externally controlled electric field where the molten particles form a plasma, which then becomes the meta electrode. The electrode on the opposite side of the electric field is formed by the growth plate 1803 shown. The Covetic material is accelerated through an acceleration zone 1821 and then deposited on the surface. The resulting alloy and Covetic material continue to deposit on the growth plate and / or on the previously deposited material in the impact zone 1823. This deposition technique results in a material with a homogenous and high carbon loading.

[0116] The input materials can be selected and modified to achieve materials exhibiting specific properties. For example, as shown, the input to the plasma spray torch can include various input gases 1812 and input metal and / or carbon particles 1818. The inputs can be introduced into one or more input ports 1862. In some cases, the input metal and / or carbon particles are entrained in the input gas 1812 flow. Furthermore, the growth plate can change its dimensions and composition as the deposition progresses. For example, as shown, the growth plate 1803 can initially be a substrate 1816 on top of which the torch flow of thermal covetic material is deposited, which at least partially melts the substrate as it is deposited. The deposited thermal covetic material is cooled from the molten or partially molten state to form a quenched layer 1824.

[0117] Any number of layers can be formed in this manner. The temperature of the substrate and / or at or near the top layer can be controlled such that when the next layer of material lands on the molten metal of the previously deposited layer, the newly deposited layer grows laterally to produce monolayer graphene on the surface of the molten metal. This mechanism distinguishes it from other techniques at least in that, in contrast to conventional metal melting methods 103 where carbon precipitates from a molten metal slurry, the application of the plasma spray torch method 104 of the present disclosure provides a quench that is short enough for carbon to precipitate out of the matrix. Thus, the covetic bonds remain intact throughout the layer. As soon as the quench forms a solid of metal and well-dispersed carbon, another layer is sprayed on top of the solid, and so on, thereby forming stacked monolayer graphene that is grown, fixed, and rapidly quenched to produce a true covetic material with extremely high carbon loading in the matrix. As an example, when using a conventional metal smelting process 103 (see FIG. 1A), carbon loadings of 6% carbon metal may be achieved. In contrast, when using a plasma spray torch process 104 (see FIG. 1A), carbon loadings of 60% are easily achieved. In some cases, strict control of the input and plasma spray torch process parameters and their environment allows carbon loadings to approach as much as 90% carbon in the resulting material.

[0118] Experimental results using a plasma spray torch have shown that high loading, highly uniform covetic layers can be formed by at least two rapid quench (e.g., "splat") methods. The first method involves covering metal particles with carbon particles (e.g., in a plasma) and spraying the resulting hot mixture onto a much cooler substrate. The second method involves producing graphene in a plasma and then covering the graphene with molten metal. In both cases, true covetic bonds (representing a combination of covalent and metallic chemical bonds) are produced while in the plasma plume, and rapid quenching of the spray serves to lock the mixture into a metal-organic lattice.

[0119] The depth or thickness of the quenched layer can be made thicker or thinner by controlling the distance between the plasma flame 1814 and the substrate, and / or by controlling the temperature of the substrate (e.g., either hotter or colder than ambient), and / or by controlling the pressure in and around the reactor.

[0120] 18B depicts a radial electric field configuration 1820 of a plasma spray torch. In this configuration, the molten particles form a plasma within the torch, which becomes the meta-electrode. The other electrode is formed by the side of the inner wall.

[0121] The configurations of Figures 18A and 18B above are merely examples. Different configurations, including different input materials and different input port configurations, are possible without departing from the concept of the plasma spray torch disclosed herein. Moreover, different configurations, including different input materials and different input port configurations, can achieve the same intended results. For example, two different configurations adjusted to obtain the same material output are shown and described in relation to Figures 18C and 18D. Specifically, the exemplary configurations of Figures 18C and 18D can be used for plasma spray torch deposition of ceramic coating material onto carbon-containing particles (e.g., graphene-containing particles).

[0122] Indeed, thin film deposition of carbon-containing materials (e.g., via atmospheric pressure chemical vapor deposition (APECVD) and / or other variants of chemical vapor deposition (CVD)) has been utilized in many areas of material processing. Various composites and coatings including such carbon-containing materials may exhibit improved physical properties (e.g., strength, corrosion impermeability, etc.). The morphological characteristics of various 2D and 3D carbons allow the composites and coatings to exhibit such improved physical properties due to the molecular level organization within the carbon-containing materials. In some cases, the use of 2D and 3D carbons in composites and coatings greatly increases the high temperature impermeability of the resulting carbon-containing materials. However, in some cases, these high temperatures are greater than about 2100° C., which is high enough for the 2D and 3D carbons themselves to burn. Unfortunately, the destruction of the 2D and 3D carbons in turn destroys the benefits originally gained by the carbon in the composite or coating. Thus, deposition techniques (e.g., plasma spray torch configurations) are needed to create composites or coatings that are temperature insensitive, even above the combustion temperature of carbon.

[0123] FIG. 18C depicts such a configuration, but this is strictly a non-limiting example. By adjusting the inputs and various reactor conditions, the graphene-containing material can be coated with a heat-absorbing layer of organically modified silicon (ORMOSIL). Deposition of ORMOSIL ceramic material onto the graphene-containing material can be accomplished in a number of ways, including through an atmospheric pressure reactive plasma-assisted chemical vapor deposition process using a silicon-containing precursor 1841 (e.g., hexamethyldisiloxane) and a reactive gas such as oxygen. This particular mixture of silicon-containing precursor and oxygen becomes reactive in the plasma. Molecular dissociation that occurs in the plasma flame leads to the deposition of silicon oxide on surfaces such as the growth plate 1803 above. To accomplish this, the reactor conditions are controlled such that as carbon-containing particles are formed in the reactor, organically modified silicon ceramic is deposited on the surface. Control of the in-reactor growth and deposition (e.g., by controlling the APECVD process) results in a thin quartz coating around the carbon-containing particles, which are then deposited on the substrate. The thin quartz coating acts as a flame retardant layer to protect the carbon-containing particles from burning at high temperatures.

[0124] FIG. 18D depicts an alternative configuration, but this is strictly by way of non-limiting example only. As shown, metal and / or carbon-containing material is loaded into a reactor. Microwave energy 1822 is controlled to achieve at least a temperature that dissociates the carbon-containing material (e.g., T(c-dissolution) in FIG. 10). Silicon-containing precursor 1841 (e.g., HMDSO, HMDSN, etc.) is introduced into the plasma flame, and the temperature decreases in the plasma afterglow. As the temperature decreases, carbon particles begin to form and become coated with silicon oxide. The silicon oxide coated carbon particles are then deposited on a substrate.

[0125] In one embodiment, a thin layer of such 3D material, approximately 10 nm thick, can be deposited on a substrate and will not burn or ignite even at 1200° C. This is because the pristine carbon (e.g., graphene) is crystallized, e.g., it is not an amorphous material. Rather, the carbon has simply been broken down to a state where it cannot be burned any more.

[0126] In one application, the plasma spray torch technique described above can be used to create new types of solder that are non-eutectic, or in another application, the plasma spray torch can spray a coating material directly onto a substrate to prevent oxidation of the underlying material.

[0127] Surrounding a material with quartz often offers significant application advantages in addition to forming a material that will not ignite even at 1200°C at atmospheric pressure.

[0128] Organically modified silicon as well as other organic materials can be used to coat the carbon particles or layers. The properties of the coating can be controlled. As an example, the porosity of the surface of the sprayed material can be adjusted to make it hydrodynamically smooth.

[0129] A plasma spray torch can be used to form glass-coated heat-absorbing non-combustible graphene composed of graphene and silicon, where the silicon coats the graphene so that the graphene can withstand high temperatures in excess of 1600° C. Such glass-coated heat-absorbing non-combustible graphene absorbs infrared energy.

[0130] One specific method for producing an organically modified silicon coating includes the following steps (for example): (1) introducing a silicon-containing precursor into a plasma spray torch apparatus, (2) mixing the silicon-containing precursor with a carrier gas containing carbon particles, which carrier gas entrains the precursor gas, and (3) coating the carbon particles with silicon.

[0131] The properties of the flame retardant and infrared opacifying material resulting from the plasma spray torch configurations of Figure 18C and / or Figure 18D can be adjusted, at least in part, by controlling the time-temperature path through the reactor. More generally, the properties of the material resulting from the plasma spray torch configurations of Figure 18A, Figure 18B, Figure 18C, or Figure 18D can be adjusted, at least in part, by controlling (e.g., pulsing) the microwave energy in the reactor.

[0132] FIG. 19 is a diagram 1900 depicting energy versus time during a pulse on and a pulse off. More specifically, this diagram shows one full time cycle, where from T=0 to 50 microseconds the microwave is continuously on, and then the remainder of the cycle depicted depicts the time the microwave is off. The plotted curves depict (1) the change in density and (2) the change in temperature over the cycle. At T=0 the temperature is at its lowest point (e.g., as depicted at the beginning of the diagram). The temperature rises rapidly and then falls, during which time the plasma density has reached a relatively stable value. When the microwave is turned off at T=50 microseconds, both the plasma density and the electron temperature over time fall rapidly. The pulse time and duty cycle can be controlled to achieve a particular density and time at any time.

[0133] FIG. 20A1 displays an image showing the organometallic bond that occurs when carbon and copper are combined using a plasma spray torch. As shown, carbon 2052 is deeply embedded in copper 2054. As generally understood and referred to herein, organometallic chemistry refers to the study of organometallic compounds, i.e., chemicals that have at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali metals, alkaline earth metals, and transition metals, and is sometimes expanded to include metalloids such as boron, silicon, and tin. Apart from bonds with organyl fragments or molecules, bonds with "inorganic" carbons such as carbon monoxide (metal carbonyls), cyanides, or carbides are also generally considered organometallic. Related compounds, such as transition metal hydrides and metal phosphine complexes, may be included in the discussion of organometallic compounds, but strictly speaking, they are not necessarily organometallic.

[0134] Within the category of organometallic chemistry, organocuprates are compounds that contain a chemical bond between carbon and copper and may have unique physical properties, synthesis, and reactivity. Organocuprates may vary in structure and reactivity, but are most commonly found in the copper(I) oxidation state, e.g., Cu + There is still a slight limitation that it is expressed as d 10 As a metal center, copper(I) is related to Ni(0), but is less involved in π-back donation due to its higher oxidation state. Organic derivatives of Cu(II) and Cu(III) are possible intermediates, but they are rarely isolated or even observed. In terms of geometry, copper(I) adopts a symmetric structure in keeping with its spherical electron shell. Typically, it can adopt one of three coordination geometries: linear bidentate, tridentate, and tetrahedral tetradentate. Organocopper compounds can be coupled with a variety of soft ligands, such as alkylphosphines (R3P), thioethers (R2S), and cyanides (CN - ) to form a complex.

[0135] By any one or more of the above techniques, the carbon depicted in Figures 20A1 and 20A2 is chemically bonded to the copper. This is in contrast to being juxtaposed with the copper and merely attached there by van der Waals forces (e.g., which represent distance-dependent interactions between atoms or molecules). Unlike ionic or covalent bonds, van der Waals attractions do not result from chemical electronic bonds. Van der Waals forces are relatively weak and therefore more susceptible to disturbances. Moreover, van der Waals forces disappear as soon as the distance between the interacting molecules increases. Instead, what is desired is an organometallic bond between the metal and the carbon.

[0136] FIG. 20A2 displays an image of a gradient composition applied to a substrate material, with three material property zones shown in the image. Bulk metal zone 2066 is the first of the three material property zones. As shown, the first material property zone includes a metal in a first crystallographic organization, the first crystallographic organization having substantial metallic bonds between metal atoms present in the first material property zone. The first material property zone is substantially adjacent to a second material property zone, which at least partially overlaps with the first material property zone. Covetic material zone 2064 includes at least some carbon atoms in a second crystallographic organization, the second crystallographic organization having at least some covalent bonds between some of the carbon atoms present in the second material property zone and some of the metal atoms present in the first material property zone. Top zone 2062 is a third material property zone, which at least partially overlaps with the second material property zone. The top zone includes additional carbon atoms oriented in a third crystallographic organization. The third crystallographic organization is characterized by having at least some covalent bonds between each of the additional carbon atoms present in the third material property zone. In various embodiments, there may be some metal atoms in any of these material property zones, and there may be some carbon atoms in any of these material property zones, but this embodiment is characterized by a metal rich zone 2074 adjacent to a bulk metal zone 2066. In various embodiments, there may be some carbon atoms in any of these material property zones here, and there may be some metal atoms in any of these material property zones there, but this embodiment is characterized by a carbon rich zone 2072 adjacent to a top zone 2062.

[0137] FIG. 20B is a material evolution diagram 20B00 depicting the resulting stacked configuration of several layers when carbon is added to bulk aluminum. In these embodiments, the material is sprayed onto an existing carbon-rich covetic substrate or carbide layer to create a carbon-carbon bond through carbon sintering and / or metal melt encapsulation, which then provides adhesion to form a composite coating. Material evolution diagram 20B00 is just one example of a combination material (silicon carbide) sprayed onto an aluminum bulk material. The process can be adjusted to create a covetic or covetic-like coating that deposits on the bulk material. The resulting material can then be coated to create a functionalized top layer. One possible configuration of an apparatus for spraying a combination material onto a substrate is presented in FIG. 21A.

[0138] FIG. 21A depicts an apparatus for spraying a molten mixture of materials onto a substrate. The diagram depicts a microwave reactor with multiple regions inside a containment vessel. Pulsed microwave energy is delivered into the containment vessel. A hydrocarbon process gas 605 is provided through an inlet. The microwave energy heats the process gas to a high enough temperature to form a plasma. The expansion of the material within the containment vessel creates a plasma plume. The continued addition of material into the containment vessel, coupled with the expansion, creates a torch effect in and around the plume. The high temperatures within and around the plasma plume result in carbon dissociating with hydrogen, thereby forming multiple different hydrocarbon species (e.g., CH3, CH2). As the temperature continues to increase (e.g., in the first region 2104 as shown), all or nearly all of the carbon atoms dissociate with hydrogen. Using any known technique (e.g., using a gas-solid separator), the hydrogen-only species are separated from the solid carbon species.

[0139] At the interface between the first region 2104 of the containment vessel and the second region 2106 of the containment vessel, molten metal or molten metal composite, or molten ceramic metal, or metal matrix, or any type of metal mixture is introduced into the containment vessel through a second inlet (as shown). The location of the second inlet is selected based on the size of the plasma plume and / or the molten metal temperature at the point of entry into the containment vessel. More specifically, the metal melt 2108 is introduced into the reactor where the molten metal mixes with the carbon species. As the mixture flows (e.g., at high velocity) through the containment vessel, the temperature of the mixture decreases. The flowing mixture exits the containment vessel at high velocity such that the carbon and molten metal mixture is sprayed from the outlet 2110. The mixture is deposited (e.g., via the spray of a thermal spray material 2112) onto a target substrate 2116. Various mechanisms for controlling the uniformity of the spray material 2112 and / or the resulting deposited material 2114 are displayed and discussed in connection with Figures 23A-23D.

[0140] The temperature of the second region is low enough that at least a portion of the carbon precipitates out of the mixture. However, most of the dissociated carbon remains in the mixture with the molten metal. Upon reaching the target substrate 2116, the molten metal mixed with the carbon cools and becomes solid. During the transition from the molten mixture to the solid deposit, the carbon becomes trapped between the metal and carbon layers. At a certain temperature, the carbon forms covalent bonds with the metal, resulting in a covetic material. The covetic material exhibits a range of mechanical, thermal, electrical, and tribological properties due to the increased cohesive forces (e.g., covalent bonds) between the metal matrix and the carbon.

[0141] Such cobetic materials are the result of utilizing pulsed microwave energy to control the energy distribution of the constituents of the material in the first and second regions of the reactor. More specifically, the energy distribution of the constituents of the material in the first and second regions of the reactor can be controlled in part by the use of pulsed microwaves and in part by premelting the metal particles in the environment external to the reactor chamber (e.g., introducing fully molten or partially molten metal into the reactor chamber). Any known technique can be used, alone or in conjunction with melting the metal particles. Thus, the degree to which the particles are fully molten or partially molten and / or intermingling can be controlled.

[0142] FIG. 21B depicts a method of thermally spraying a Covetic material onto a substrate. This method can be used in conjunction with the apparatus of FIG. 21A. As shown, the method is performed using a microwave reactor with an inlet for a process gas, an inlet for a metal melt, and an outlet. Prior to operation, the microwave reactor is positioned (operation 21B02). In operation 21B10, the inlet serves to introduce a hydrocarbon process gas into a first region of the reactor. Microwave energy is used to increase the temperature of the first region of the reactor so that the hydrocarbon process gas dissociates into carbon and hydrogen species before reaching the metal melt. A different inlet serves to introduce the metal melt into a second region of the reactor (operation 21B20). The elevated temperature in the second region is maintained until the dissociated carbon mixes with the metal melt (operation 21B30). The effect of the plume serves to move the mixture into a third region of the reactor (operation 21B40). Movement away from the microwave energy source has the effect of lowering the temperature of the mixture until at least a portion of the carbon comes out of the mixture by condensation (operation 21B50). However, even as the temperature is lowered, the plasma torch effect serves to move the mixture through an outlet at high velocity (operation 21B60). The molten mixture is then sprayed onto a substrate (operation 21B70).

[0143] FIG. 21C is a schematic diagram depicting the plasma spray process used to spray the coating. As shown, carbon radicals, polycyclic aromatics, graphene sheets, and metal particles are mixed at high temperature in a plasma reactor (see, for example, first region 2104 of the figure). Nucleation occurs at these high temperatures, and as the temperature in the reactor decreases (see, for example, second region 2106 of the figure), growth and assembly begins. One possible growth mechanism depicts sub-micron sized aluminum particles being coated with few-layer graphene. The sub-micron sized aluminum particles are held together by a combination of metallic, covalent, and covetic bonds. More specifically, and as shown on a 2 nm scale, carbon atoms are bonded to aluminum atoms. The carbon atoms are organized in coherent graphene planes located in the aluminum matrix. The above discussion including aluminum is by way of example only. Other metals can also be used. In fact, coherent graphene planes can be located not only in a face-centered cubic (FCC) metal lattice, but also in a body-centered cubic (BCC) metal lattice, or even in a hexagonal close-packed (HCC) metal lattice.

[0144] The coated particles are then sintered to form particles having diameters on the order of 100 microns. These semi-molten particles are then accelerated through a reactor and impinged on a substrate (e.g., in a first pass) or against a previously deposited layer of impinging particles (e.g., in a second or Nth pass).

[0145] Figure 22A is an apparatus for enveloping carbon particles with molten metal. The configuration of the apparatus of Figure 22A differs from that of Figure 21A at least in that the introduction of molten metal is controlled using melter 2209. The metal melt is controlled to produce molten metal that envelops the carbon particles when introduced into the reactor.

[0146] FIG. 22B depicts a method of encasing carbon particles in molten metal. This method differs from the method of FIG. 21B at least in that, in operation 22B30, temperatures in different regions of the reactor are maintained such that some of the carbon particle species are formed from dissociated carbon. In operation 22B50, at least some of the carbon particles are encased in molten metal. Some bonds are formed between the constituent atoms of the carbon particles and the atoms of the molten metal. In operation 21B60, the metal-encased carbon particles move through an outlet and are further cooled. As the metal-encased carbon particles are deposited on a substrate (operation 21B70), additional bonds are formed between the metal-encased carbon particles and the metal of the substrate.

[0147] 23A, 23B, 23C, and 23D depict examples of deposition techniques according to some embodiments.

[0148] As shown in FIG. 23A, the deposited material has a curved shape characterized by a high middle region and a lower end region. In some cases, this is the desired shape for spot-deposited material. In other cases, it is desirable to spray the deposited material over a larger area. This can be accomplished by moving the substrate relative to the sprayed material, or by moving the substrate relative to the substrate. FIG. 23B shows a movable substrate 2310 positioned on a supply reel. The movable substrate can be pulled up or wound onto a take-up reel. As such, and in the configuration of FIG. 23B, the sprayed covetic material is deposited uniformly on the moving substrate. When the relative movement between the sprayed material 2112 and the substrate is controlled, the resulting deposited material is of uniform thickness.

[0149] In some situations, it is desirable to have a non-flat, but uniform pattern on the surface of the deposited material. In such cases, the movement of the substrate can be stepped through a series of discrete positions, resulting in the pattern of FIG. 23C. Additionally or alternatively, a slotted antenna can be placed between the material to be sprayed 2112 and the substrate. The slotted antenna works by distributing the spray evenly across the lateral distance of the slotted antenna. Using such a slotted antenna, a single portion of the sprayed material 2112 can have a thickness and surface uniformity substantially as shown in FIG. 23D.

[0150] 24A and 24B depict conventional techniques for depositing materials onto a substrate. As shown in FIG. 24A, carbon agglomerates are held together through the use of a binder (e.g., a polymer additive). This results in a weak bond at the interface between the carbon agglomerates and the substrate. FIG. 24B depicts the coating of a carbon material onto a substrate using a binder. Conventional deposition methods using binders suffer from delamination problems. Moreover, even when the surface of the substrate is mechanically pretreated and / or pretreated with a binder material deposition, the interaction between the substrate and the carbon agglomerates is weak.

[0151] As has been explained thus far, coatings based on depositing materials onto a substrate using binders and / or coating techniques (such as those shown and described in connection with Figures 24A and 24B) suffer from problems with delamination, low strength properties, and other undesirable mechanical properties. An improvement based on plasma spray techniques is shown and discussed in connection with Figures 25A and 25B.

[0152] 25A and 25B depict exemplary deposition techniques that provide covalent bonds to the surface of a substrate, according to some embodiments. Specifically, and as shown, when using the techniques of the present disclosure, covetic materials are formed by covalent bonds between carbon and the substrate. Therefore, no bonding agent is required or used. Moreover, many of the bonds formed at the interface between the substrate and the covetic material are strong covalent bonds. In one specific example, the substrate is aluminum, and the covalent bonds are formed between the atoms in the face-centered cubic structure of aluminum and the carbon atoms in the hexagonal structure. A schematic diagram of the interface bonds is displayed in FIG. 25B.

[0153] Figures 26A, 26B, 26C, and 26D provide schematic diagrams illustrating how covalent bonds form between sites in the squares of the face-centered cubic structure of aluminum and sites in the hexagons that occur in certain crystallographic structures of carbon.

[0154] Figure 26A is an orthogonal view showing the squares of the face-centered cubic structure of aluminum, and Figure 26B is an orthogonal view showing the hexagons that occur in certain crystallographic structures of aluminum.

[0155] Figure 26C depicts one possible way that a hexagon occurring in certain crystallographic structures of carbon can be superimposed on top of the square of the face-centered cubic structure of aluminum. Figure 26D shows the covalent bonds that form at certain sites. The example of the face-centered cubic structure of aluminum is just one example. Other materials with other crystallographic structures are possible.

[0156] FIG. 26E is an example of a laminated Cobetic material 26E00, where the graphene-like structure is sandwiched between layers of metallic material. The lower metallic material layer is the substrate layer. The upper metallic material layer is formed of quenched material that was previously molten while in the reactor. The graphene-like structure sandwiched between the layers of metallic material is trapped between the two metallic layers by the formation of metal-metal bonds between the two metallic layers. In addition to the metallic bonds, other bonds are formed that serve to confine the graphene-like material between the metallic layers. At multiple locations, defects exist in the carbon lattice. Various types of bonds are formed between or near such defects.

[0157] Any or all of the above techniques for forming covetic materials can be used in many applications, including on a wide variety of substrates. Moreover, the relative movement between the spray and the substrate can be controlled to provide any thickness of deposition. Any known technique can be used to control the relative movement. For example, the outlet can be moved relative to a fixed substrate. This can be accomplished using a handheld device or a machine-controlled device that moves relative to a fixed substrate. In some cases, a bias voltage can be applied to the substrate such that at least a portion of the material sprayed out of the outlet is electrically attracted to the substrate surface. This can be applied to applications where the substrate does not have a uniform flatness. By way of example, applications where the substrate does not have a uniform flatness can include: (1) molded components used in machines that are subject to severe corrosive conditions, (2) turbine blades, (3) heat exchanger components, etc. Many of these applications are discussed further below.

[0158] In other situations, the deposit properties (e.g., thickness, lateral uniformity, etc.) can be improved through the use of various chemical vapor deposition techniques and / or combinations thereof. As just one example, aspects or parameters of plasma-assisted chemical vapor deposition techniques known in the art can be controlled to optimize the properties of the deposited Covetic material layer. As another example, rather than depositing the Covetic material on a surface to form a film or coating, the Covetic material can be formed into particles (e.g., by thermal spraying into a cryogenic environment) and the particles collected as a powder. Various techniques involving the production and use of powdered Covetic materials are briefly discussed below.

[0159] Powdered Cobetic Materials In some circumstances, the Covetic material can be delivered as a Covetic material powder rather than being formed on or in a substrate as a film or coating. Such powdered Covetic material can be collected by cooling the Covetic material as it exits the reactor to a temperature below the melting point of the Covetic material and collecting it as a powder. The powder can then be handled (e.g., stored, transported, poured, mixed, etc.) at room temperature. The powder can then be remelted and compression molded or remelted and resprayed. As an example, components used in highly corrosive environments can be formed from such powdered Covetic material using injection molding or extrusion. Many devices can be used alone or in combination to form and transport the Covetic material powder. Example devices are shown and described in connection with Figures 27A and 27B.

[0160] FIG. 27A depicts an example apparatus 27A00 for producing powdered Covetic material 2710, which uses a cooling region 2702 to cool the sprayed material 2112 as it is extruded through the microwave reactor outlet 2110. Any one or more cooling techniques, in any combination, can be used to reduce the temperature of the Covetic material in the cooling region 2702 to a temperature below the melting point of the Covetic material. The cooling region 2702 can contain one or more devices to cause cooling. For example, and as shown, the collection vessel 2704 can be fitted with one or more devices to cause a cyclone effect in the collection vessel, thereby extending the time for reducing the temperature of the Covetic material. In some cases, the cooling time of the Covetic material is controlled (e.g., by extending or shortening the time) so that the Covetic material is annealed with highly regular bonds. In some cases, controlling the time that the Kobetic material is cooled allows the Kobetic material to crystallize into a highly regular crystal structure while remaining in a powder form. In some embodiments, a mechanical tumbler agitator can be installed between the microwave reactor outlet 2110 and the collection vessel 2704. The tumbler agitator can be periodically cleaned or replaced.

[0161] Alternatively or additionally, and in situations where it is convenient and / or necessary to contain and / or transport the powdered cobetic material in a fluid, a fluidized bed apparatus can be used. For example, the powdered cobetic material can be kept in a liquid to avoid particle agglomeration of the powder. In some embodiments, a fluidized bed apparatus can be mounted between the microwave reactor outlet 2110 and the collection vessel 2704. One embodiment of such a fluidized bed apparatus is shown and described in connection with FIG. 27B.

[0162] FIG. 27B depicts an example fluid bed apparatus 27B00 for cooling and handling powdered cobetic material in a fluid.

[0163] As shown, the molten metal and carbon mixture is forced through the reactor outlet and into the top of the fluidized bed 2750. As the molten metal and carbon mixture is forced through the outlet, it cools in a manner that forms particles. The particles are subjected to a downward force of gravity (e.g., in a downward direction as shown) while simultaneously, the process fluid 2754 is forced from the bottom of the fluidized bed, creating an upward force. Thus, the particles accelerate toward the bottom of the fluidized bed, but at a slower rate than the local gravitational acceleration. The dynamics of the flow can be controlled in part by the geometry of the fluidized bed. For example, as shown, a length of the fluidized bed can be a tapered body 2762, with a first end of the tapered body having a first dimension D1 and a second end of the tapered body having a second dimension D2, where D1>D2. The temperature within each portion of the fluidized bed can be controlled, in part, by a power supply 2752 that provides power to the coils (as shown) and / or by a heat source 2760 that heats the process fluid 2754 before it enters the bottom of the fluidized bed.

[0164] The pressure and flow rate and other conditions within the fluidized bed and at the bed's environmental interfaces act to cause the powder and fluid mixture to together behave as a fluid, exhibiting fluid properties and characteristics, such as the ability to flow freely under gravity and / or be transportable using fluid handling techniques.

[0165] 27B, the fluidized bed has multiple ports at various heights in a tapered body such that a fluid containing a first powder 27561 flows out at a particular temperature / pressure while a fluid containing a second powder 27562 flows out at a second, different particular temperature / pressure. The flow through the multiple ports can be controlled such that a collection vessel can receive the fluid containing first powder 27561 and the fluid containing second powder 27562 in any ratio or amount.

[0166] Method for forming Covetic material Table 3 provides some non-limiting examples of methods for forming powdered Covetic materials. [Table 3]

[0167] Method 1 In some embodiments of method 1, in a first region of a microwave reactor, structured carbon (e.g., carbon allotropes) is formed (e.g., through dissociation of a hydrocarbon process gas). In a second region, at a lower temperature than the first region, the structured carbon is modified with a metal to form a metallized carbon material (e.g., organometallic material). The metallized carbon material is further cooled to a temperature below the melting point of the metal. In some embodiments, the metallized carbon material is initially in the form of carbon particles modified with a metal. The particles are further cooled to form a powder. The powder can be collected and transported to a utilization facility. The powder containing the metallized carbon material with cobetic bonds can be remelted and used in conjunction with any known technique for forming components from powders. Strictly by way of example, components can be formed from the powder by using stamping followed by remelting, isostatic pressing followed by remelting, hot casting, metal injection molding, laser sintering, and the like.

[0168] Method 2 In this method 2, one or more hydrocarbon gases (or gases and liquids, as the case may be) are introduced into the system. By way of example only, gases and / or liquids that may be introduced into the system include methane, ethane, methylacetylene-propadiene propane (MAPP), and hexane. In a first region 2104 at a first temperature, carbon atoms dissociate from other atoms (e.g., hydrogen). Molten metal 2108 is introduced into the reactor as metal particles. Then, in a second region 2106, carbon produced in the first region combines with the metal particles. Carbon grows on the surface of the metal particles and / or grows within the metal particles. In some situations and under some conditions, carbon growth includes 2D carbon growth on or within the metal particles. In other situations and / or under other conditions, carbon growth includes 3D carbon growth on or within the metal particles. In any of the above growth situations, growth can proceed to the maximum extent that the lattice allows. For example, the molten metal can be aluminum with a face-centered cubic (FCC) crystal structure, and carbon can form a solid solution with the aluminum up to a certain concentration. In some embodiments, the carbon forms a solution with the metal up to a concentration determined by the properties (e.g., crystal structure) of the metal, and then precipitates out of the metal-carbon solution to form 2D or 3D carbon on and / or within the metal particles.

[0169] Growth in this method 2 is performed under non-equilibrium temperature conditions. Specifically, a variety of different temperature conditions are used to control (for example): (1) a first temperature in the first zone (e.g., hot side) required to control the dissociation, and (2) a second temperature in the second zone (e.g., cold side) to control the initial melting of the metal powder in the second zone and / or the formation and properties of the metal-carbon particles. The temperatures in these two zones can be independently controlled. With this method, the sprayed material is a true cobetic material that exhibits true cobetic behavior.

[0170] Method 3 In yet a further non-limiting example, materials and / or coatings can be generated or deposited on input particles from mixed materials, such as trimethylamine (TMA), trimethylglycine (TMG), and methylacetylene-propadienepropane. The particles can be cooled and collected as a powder. Some examples of particles that can be generated from target materials in the first zone include phased carbon, silicon carbide, metal oxides, metal nitrides, or metals. In some cases, the input particles are metals and a compound coating (e.g., metal oxides or metal nitrides) coats the input metal particles, while in other cases, the input particles contain compound materials and a metal coating is deposited on the input particles. Some examples of particles that can be generated from input gas in the first zone include carbon allotropes (e.g., intrinsic carbon), silicon, ZnO, AlOx, and NiO.

[0171] In some embodiments, gases, including various non-hydrocarbon gases or alcohols, are introduced into a first zone, which includes a sputtering device and a power supply, the sputtering device configured to generate a plurality of ion species from a selected target material. The target material and the ion species combine to form a plurality of particles. The power supply can be an AC, DC, RF, or high power impulse magnetron sputtering (HIPIMS) power supply, and can be configured to generate a plurality of ion species from the target material by adjusting the power, voltage, frequency, repetition rate, and / or other characteristics of the power supply.

[0172] FIG. 27C is a schematic diagram depicting the plasma spray process used to manufacture powdered Covetic material.

[0173] Powder material processing sequence 27C shows a visual representation of an example powder material processing sequence from hydrocarbon decomposition and particle nucleation (e.g., first region 2104 of the figure), through graphene growth (e.g., second region 2106 of the figure), cooling of the semi-molten particles (e.g., cooling region of the figure), and collection of the powdered cobetic material (e.g., in the collection region and into collection vessel 2104). The mechanisms underlying the effectiveness of the example powder material processing sequence will now be briefly discussed.

[0174] In the absence of metal precursors (whether in metalorganic or particulate form), the microwave plasma dissociates methane to form carbon radicals (as well as polycyclic aromatics / acetylenes), which then form few-layer (FL) graphene (or stacked lamella) structures, respectively. However, in the presence of metal precursors in the plasma zone (e.g., reactors shown in Figures 21A and 22A), the metals (either from metalorganic nuclei or particles) can act as seeds for heterogeneous carbon growth (e.g., carbon in the form of ionized radicals, graphene nuclei, or polycyclic aromatics (acetylenes)).

[0175] When using less soluble metals, such as Al or Cu, graphene sheets can grow on the metal surface (e.g., either through adatoms / monomers or as clusters). The characteristics of the growth depend, at least in part, on the symmetry and interfacial free energy minimization at the metal surface. Thus, carbon growth occurs at the metal particles in parallel with metal atom resputtering events at the surface, producing mixed and / or stacked metal / carbon structures. As is known in the art, the radius (e.g., surface curvature) of the metal particles can affect the solubility of carbon in the metal particles. As an example, a smaller radius (e.g., corresponding to a higher curvature) increases the solubility to equilibrium (at a flat surface), which in turn can affect the thickness of the graphene layer.

[0176] Once the powdered Covetic material 2710 has been collected in a collection vessel, the powdered Covetic material may be further processed using conventional techniques (eg, injection molding techniques, other techniques using powdered metals).

[0177] Manufacturing techniques using powdered Covetic materials. 28 depicts a method of fabricating components from powdered Covetic material using injection molding techniques. As shown, the method begins by assembling a set of properties for components to be used in a particular application and / or environment (operation 2810), and then selecting a particular powdered Covetic material based on at least one of the properties for that application or environment (operation 2820). The selection may be based on mechanical properties desired for the component, and / or based on corrosion resistance desired for the component in an environment corresponding to the intended use, and / or based on other desired properties. The selection may be based on multiple desired properties, and in some cases the selection tool may be capable of solving an optimization problem based on the set of properties and an objective function.

[0178] Once a Covetic material is selected (operation 2820), the selected powdered Covetic material 2825 is melted (operation 2830) and introduced into a mold (operation 2840). A predetermined temperature and pressure are maintained inside the mold for a predetermined period of time (operation 2850), after which the temperature and pressure inside the mold are brought to about 30° C. and about atmospheric pressure (operation 2860). The component is released from the mold (operation 2870) and deployed in its intended application (operation 2880).

[0179] As described thus far, the selection of a particular Covetic material may be based on a number of desired properties, some of which may be used as variables in an objective function. In some cases, the selection of a particular Covetic material may be based on a particular dominant property (e.g., mechanical strength, weight, corrosion resistance, etc.). In some cases, the property of interest is a ratio with respect to other properties (e.g., strength to weight, specific heat to weight, etc.). In some cases, the dominant property is subject to maximization (or minimization) with respect to one or more constraints imposed on the other properties.

[0180] As such, powdered Kobetic materials can be deployed in a wide range of applications. In many cases, the resulting components made from powdered Kobetic materials are superior to components made from other materials. Some examples of uses that correlate with certain dominant properties are displayed and discussed in connection with FIG. 29 below.

[0181] Figure 29 depicts various properties of Covetic materials. The properties include mechanical properties, thermal conductivity, oxidation resistance, durability, resistance to softening at high temperatures, fatigue resistance, and electrical conductivity. Individual parameters and / or combinations of these parameters may govern when selecting a particular Covetic material for a particular application.

[0182] As a strict example, oxidation resistance may be the governing parameter when selecting a Covetic material for use in manufacturing corrosion resistant valves. As another example, when selecting a particular Covetic material for use in manufacturing a turbine blade for an airplane engine, mechanical attributes, e.g., strength-to-weight ratio, subject to strength minimum constraints, may be the governing mechanical attributes. The blade may also need to exhibit very high fatigue resistance.

[0183] Typically, the Covetic material not only exhibits the above properties, but also exhibits a lower density than the metal or alloy used to make the Covetic powder. The lower density often results in a correspondingly lighter weight of the formed component compared to the same component made from the metal or alloy in the absence of carbon addition. Thus, truck parts (e.g., cab components as shown), automobile parts (e.g., doors, fenders, roof panels, etc.), motorcycle parts, bicycle parts, and various components (e.g., structural members) of aircraft, and / or watercraft, and / or space vehicles or platforms can take advantage of the lower strength-to-weight ratio of the Covetic material compared to the base metal or alloy used to make the Covetic material.

[0184] As another example, Covetic materials often exhibit exceptional thermal conductivity such that components formed from Covetic materials can be used in high temperature applications (e.g., heat sinks for electronic devices, industrial heat exchangers, etc.).

[0185] As yet another example, Covetic materials often exhibit exceptional corrosion resistance. More specifically, Covetic laminates made using the techniques described above exhibit exceptionally high corrosion resistance, even at the top layers (e.g., at the component-environment interface). This property is of particular interest when components made with Covetic materials are exposed to harsh environments.

[0186] As yet another example, the Covetic material can adjust the surface smoothness. More specifically, the Covetic laminate made using the above technique exhibits exceptionally high surface smoothness. This surface smoothness is of particular interest when the Covetic material acts as a heat shield, for example, when friction at the surface (e.g., friction caused by fluids flowing over the surface at high speed) may be required in applications that result in undesirable heat generation at the surface. By using the techniques of the present disclosure, a hydrodynamically smooth surface can be obtained for certain compositions of Covetic materials and / or by using certain techniques of the present disclosure for depositing Covetic materials, which can then be used for aeronautical and / or space vehicles.

[0187] In certain embodiments, one set of properties may dominate over other properties. For example, the surface of a space vehicle (e.g., a satellite) may be required to be substantially non-reflective over a range of electromagnetic radiation (e.g., substantially non-reflective of visible light), while at the same time, the surface of the space vehicle may be required to be thermally insulating (e.g., thermally non-conductive). The tuning techniques described above address situations where a particular desired property (e.g., non-reflective) governs the tuning of a plasma spray torch to produce a substantially non-reflective surface at the expense of other properties.

[0188] The properties as displayed and described in relation to Figure 29 are exemplary only. Additional properties and / or combinations of properties may be required or desired in various applications, and such additional properties are exhibited in the resulting material based on adjustment of the inputs and control of the plasma spray torch. Strictly by way of example of the additional properties listed above, such properties and / or combinations of properties may include or relate to strength to weight ratio, and / or specific gravity, and / or mechanical toughness, and / or shear strength, and / or flexural strength, etc.

[0189] In the above specification, the present disclosure has been described with reference to specific embodiments thereof, but it will be apparent that various modifications and changes can be made thereto without departing from the broader spirit and scope of the present disclosure. For example, the process flows above are described with reference to a particular order of process acts. However, the order of many of the described process acts can be changed without affecting the scope or practice of the present disclosure. The specification and drawings should be taken in an illustrative and not a limiting sense.

Claims

1. 1. A composition of matter comprising: No carbon agglomerates, having one or more particles, at least a portion of the one or more particles independently comprise a metal lattice having one or more planar layers of graphene disposed within the metal lattice; 13. A composition of matter wherein said one or more planar layers of graphene consist of a monolayer of said graphene.

2. 2. The composition of matter of claim 1, wherein at least a portion of the carbon atoms of the one or more planar layers of graphene are positioned at sites between the metal lattices.

3. 10. The composition of matter of claim 1, wherein the metal grid comprises one or more metals selected from the group consisting of aluminum, copper, nickel, titanium, tantalum, and combinations thereof.

4. 2. The composition of matter of claim 1 , wherein the one or more planar layers of graphene have at least 5 layers of graphene and up to 15 layers of graphene.

5. 2. The composition of matter of claim 1, wherein at least some of the carbon atoms in the one or more layers of graphene are covalently bonded to other carbon atoms in the one or more layers of graphene.

6. 10. The composition of matter of claim 1, wherein the one or more planar layers of graphene are each independently substantially free of defects.

7. 2. The composition of matter of claim 1, wherein the metal lattice is characterized by a crystal structure selected from face-centered cubic (FCC), body-centered cubic (BCC), and hexagonal close packed (HCC).

8. 10. The composition of matter of claim 1, wherein each particle is characterized by a lack of agglomerates and / or agglomerates of carbon at the grain boundaries between each particle.

9. 10. The composition of matter of claim 1, wherein each of the one or more particles is characterized by a diameter in the range of about 20 nm to about 40 μm.

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