Hardmetal powder for binder jet additive manufacturing

Abstract

A method for manufacturing three-dimensional (3D) objects is provided by forming a fully densified printable cemented carbide powder through a two sintering cycle process, which is then used in binder jet additive manufacturing to 3D print the object.

Description

[Technical field]

[0001] The present disclosure relates to a method for producing three-dimensional (3D) objects by binder jet additive manufacturing. [Background technology]

[0002] Additive manufacturing (ALM) typically involves the adoption of digital three-dimensional (3D) design data to 3D print physical articles or components by means of successive material and liquid binder deposition and subsequent processing to form successive layers. There is growing evidence to suggest that the ALM market is rapidly maturing, resulting in increased interest, particularly from manufacturers, in producing physical products and components in a timely manner. Indeed, a myriad of technology options have been developed that traditionally fall under the general category of ALM. Further in this regard, traditional 3D technologies can include, but are not limited to, stereolithography incorporating UV lasers to cure photopolymers, inkjet printers that utilize UV ​​radiation to polymerize photomonomers and photooligomers, metal sintering (e.g., selective laser sintering and direct metal laser sintering), fused deposition modeling (FDM based on extrusion technology), and deposition of liquid binder onto powder.

[0003] In the context of ALM, such 3D printing techniques have emerged as an attractive tool for manufacturing physical articles and components in a variety of different fields, such as architecture, construction (AEC), industrial design, automotive, aerospace, military, engineering, dental and medical industries, biotechnology (e.g., human tissue replacement), fashion, footwear, jewelry, eyewear, education, geographic information systems, food, and many others. A compelling motivation for adopting ALM is that it offers an efficient and cost-effective alternative to the traditional and more routinely used part manufacturing techniques based solely on molding processes. The use of ALM can eliminate the significant time and expense of mold and / or die fabrication, as well as other tooling fabrication. Indeed, ALM techniques provide an efficient utilization of materials by allowing in-process recycling and eliminating the need to employ mold lubricants and coolants. In short, ALM advantageously offers manufacturers a wide range of options and freedom in article design. Importantly, the result is that highly complex shaped articles can be manufactured without great expense and hassle.

[0004] In the ALM technology platform for 3D printing objects, binder jet additive manufacturing, or simply binder jetting, is a next-generation technology that encompasses a well-defined ALM process. An industrial print head selectively deposits a liquid binder onto a thin layer of powder particles, which can be metal, sand, ceramic, or composite. This process is repeated sequentially, with successive layers being added using specially created maps from a digital design file, until finally the object is 3D printed and cured.

[0005] Thus, the liquid binder acts as an adhesive, much like glue, between multiple additive and accumulated powder layers. The binder is generally in liquid form, and the build material is in powder form. The print head moves horizontally along the x and y axes of the machine, sequentially depositing alternating layers of build material and liquid binder material. After each successive layer, the object to be 3D printed is lowered onto its build platform.

[0006] One of the fundamentally significant obstacles commonly faced is the inability to obtain pore-free parts after furnace sintering. Thus, in hardmetal powders, there is a trade-off between good and sufficient flowability (i.e., ideally the particles should not sinter together) and producing a sufficiently high density that is typically required for binder jetting. It is therefore essential to consider this trade-off when producing hardmetal powders for the purposes of binder jetting.

[0007] In view of the above, there is a need in the art of ALM for a method for producing high density cemented carbide for use in binder jetting for 3D printing objects, which method addresses the aforementioned problems. Summary of the Invention

[0008] According to a first aspect, a method for manufacturing a three-dimensional (3D) object is provided, the method comprising preparing a slurry composition comprising a ceramic hard phase powder, a metal binder phase powder, and an organic binder in a grinding liquid. The slurry composition is then ground to obtain a slurry blend, and the slurry blend is then spray-dried to obtain an RTP powder. After sieving the RTP powder, the RTP powder is then pre-sintered in a first cycle to densify the RTP powder. The pre-sintered RTP powder is then sintered in a second cycle to form a more densified printable powder. After sieving the formed printable powder, the formed printable powder is subjected to binder jetting to 3D print a green body. The 3D printed green body is then cured and sintered to finally form the 3D object.

[0009] Optionally, the RTP powder is free-flowing.

[0010] Optionally, the pre-sintering in the first cycle is carried out at a temperature starting at about 550°C and ending at about 1250°C.

[0011] Optionally, the pre-sintering in the first cycle is carried out in an atmosphere with a hydrogen pressure of up to about 35 mbar and a hydrogen flow rate of up to about 6000 liters / hour.

[0012] Optionally, the pre-sintering in the first cycle is carried out for about 15 minutes to about 30 minutes.

[0013] Optionally, the pre-sintering in the first cycle is carried out for about 30 minutes to about 45 minutes.

[0014] Optionally, the second cycle sintering is carried out at a temperature starting at about 550°C and ending at about 1250°C.

[0015] Optionally, the second cycle sintering is carried out in an atmosphere with an argon pressure of up to about 50 mbar and an argon flow rate of up to about 300 liters / hour.

[0016] Optionally, the second cycle sintering is carried out for about 15 minutes to about 30 minutes.

[0017] Optionally, the second cycle sintering is carried out for about 30 minutes to about 45 minutes.

[0018] Optionally, the yield of the formed printable powder is between about 60% and about 90%.

[0019] Optionally, the yield of the formed printable powder is between about 70% and about 90%.

[0020] Optionally, the yield of the formed printable powder is about 80% to about 90%.

[0021] Optionally, the yield of the formed printable powder is about 85% to about 90%.

[0022] Optionally, the yield of the formed printable powder is at least 90%.

[0023] The apparent density of the RTP powder and the printable powder is at least about 5 g / cm 3 ~Approx. 15g / cm 3 The range is.

[0024] Optionally, the ceramic hard phase comprises one or more of tungsten carbide (WC), titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), vanadium carbide (VC), zirconium carbide (ZrC), molybdenum carbide (MoC) or hafnium carbide (HfC), or any combination thereof.

[0025] Optionally, the ceramic hard phase comprises WC.

[0026] Optionally, the metallic binder phase powder comprises cobalt.

[0027] Optionally, the RTP powder is sieved through a 4 mesh screen, a 6 mesh screen, an 8 mesh screen, a 12 mesh screen, a 16 mesh screen, a 20 mesh screen, a 30 mesh screen, a 40 mesh screen, a 50 mesh screen, a 60 mesh screen, a 70 mesh screen, an 80 mesh screen, a 100 mesh screen, a 140 mesh screen, or a 200 mesh screen.

[0028] Optionally, the printable powder is sieved through a 4 mesh screen, a 6 mesh screen, an 8 mesh screen, a 12 mesh screen, a 16 mesh screen, a 20 mesh screen, a 30 mesh screen, a 40 mesh screen, a 50 mesh screen, a 60 mesh screen, a 70 mesh screen, an 80 mesh screen, a 100 mesh screen, a 140 mesh screen, a 200 mesh screen, a 230 mesh screen, a 270 mesh screen, a 325 mesh screen, or a 400 mesh screen.

[0029] Optionally, curing of the 3D printed green body is carried out at a temperature starting at about 150°C and ending at about 180°C.

[0030] Optionally, curing of the 3D printed green body is carried out at a temperature starting at about 180°C and ending at about 200°C.

[0031] Optionally, curing of the 3D printed green body is carried out for up to about 6 hours.

[0032] Optionally, curing of the 3D printed green body is carried out at a temperature starting at about 1500°C and ending at about 1560°C.

[0033] Optionally, curing of the 3D printed green body is carried out at a temperature starting at about 1560°C and ending at about 1600°C.

[0034] Optionally, the printable powder is fully densified.

[0035] Other systems, methods, features and advantages will be or become apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. All such additional systems, methods, features and advantages are intended to be included herein, be within the scope of the disclosure, and be protected by the following claims. Nothing in this section should be construed as a limitation on the scope of these claims. Further aspects and advantages are described below in connection with embodiments of the disclosure. It is to be understood that both the foregoing general description and the following detailed description of the disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure as set forth in the claims.

[0036] The accompanying drawings, which are included to provide a further understanding of the subject matter and are incorporated in and constitute a part of this specification, illustrate embodiments of the subject matter and, together with the description, serve to explain the principles of the disclosure. [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 is a flow diagram illustrating the individual process steps of producing high density cemented carbide powder for binder jetting to 3D print objects, according to an exemplary embodiment of the present subject matter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the currently described subject matter pertains.

[0039] When a range of values, e.g., a concentration range, percentage range, or ratio range, is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limit of that range, and any other stated or intervening value in that stated range, is encompassed within the described subject matter, unless the context clearly dictates otherwise. The upper and lower limits of these narrower ranges may be independently included in the narrower range, and such embodiments are also encompassed within the described subject matter, but subject to any specifically excluded limit in the stated range. When a stated range includes one or both of the limits, ranges excluding one or both of those included limits are also included in the described subject matter.

[0040] The following definitions define the parameters of the described subject matter.

[0041] As used herein, the term "additive manufacturing (ALM)" refers to a process that employs digital three-dimensional (3D) design data to produce physical articles or components in various successive layers by alternating successive methods of depositing and processing powder materials and liquid binders. Recent years have seen a convergence of breakthrough technologies in 3D printing objects, such as fused deposition modeling (FDM) and binder jetting, which are examples of such next-generation ALM processes. An industrial print head selectively deposits a liquid binder onto a thin layer of powder particles, which can be metal, sand, ceramic, or composite materials. This process is repeated in sequence, with successive layers being added using specially created maps from the digital design file, until the object is finally 3D printed and cured.

[0042] As used herein in the specification of the present disclosure, the term "RTP powder" refers to a milled, spray-dried, pressable cemented carbide powder that includes a mixture of a ceramic hard phase and a metallic binder phase, including cobalt, having a particle size typically ranging from about 10 microns to about 250 microns. The RTP powder is sieved and then densified, which is facilitated by a first pre-sintering consolidation step. This is then followed by a second sintering cycle step to finally increase the particle density of the cemented carbide powder and further densify it to obtain a fully densified "printable powder." Thus, further densification of the RTP powder by the second sintering cycle forms a fully densified printable powder. After sieving, the formed fully densified printable powder is then used in binder jet additive manufacturing to 3D print a green body.

[0043] As used herein, the term "curing" refers to a chemical or physical process that results in toughening or hardening by cross-linking of chains. Curing can include chemical reactions such as polymerization, or physical reactions such as evaporation that result in more stable chain cross-links.

[0044] As used herein, the term "sintering" refers to the process of heating under controlled pressure to minimize the surface area of ​​a particle system, which is associated with the creation of bonds between adjacent particles or granules and the shrinkage of agglomerated particles or granules. The compression and formation of a dense bulk mass is accomplished by heating the particles to their liquidus point without melting them. Atoms within the particles diffuse across the particle boundaries, fusing the particles together into one solid bulk piece.

[0045] As used herein, the term "sphere" refers to a solid, round shape with all points on its surface located equidistant from its center.

[0046] As used herein, the term "wt. %" refers to a given weight percent based on the total weight of a high density cemented carbide for binder jet additive manufacturing for 3D printing an object, unless otherwise specified.

[0047] As used herein, the term "D50" refers to a particle size corresponding to 50% of the sampled particles' volume being smaller than the stated D50 value and 50% of the sampled particles' volume being larger than the stated D50 value. Similarly, the term "D90" refers to a particle size corresponding to 90% of the sampled particles' volume being smaller than the stated D90 value and 10% of the sampled particles' volume being larger than the stated D90 value. The term "D10" refers to a particle size corresponding to 10% of the sampled particles' volume being smaller than the stated D10 value and 90% of the sampled particles' volume being larger than the stated D10 value. The width of the particle size distribution can be calculated by determining the span, which is defined by the formula (D90-D10) / D50. The span indicates how far apart the 10th and 90th percentiles are, normalized at the midpoint.

[0048] To determine the average grain size from a given grain size distribution for a sintered microstructure, a person skilled in the art can easily understand the ISO 4499-2:2008 standard, which provides guidelines for the measurement of grain size in hard metals by metallographic techniques employing optical or electron microscopy. It is intended for sintered WC / Co hard metals, which contain mainly WC as the ceramic hard phase. It is also intended to measure grain size and grain size distribution by the linear intercept method.

[0049] To further supplement the ISO 4499-2:2008 standard, those skilled in the art will be equally familiar with the ASTM B390-92 (2006) standard, which is used to empirically visually compare and classify the apparent grain size and distribution of tungsten carbide alloys, which typically contain cobalt as a metallic binder in the binder phase.

[0050] Cemented carbide grades can be classified by grain size. Different types of grades of different materials are defined as nano, ultrafine, submicron, fine, medium-fine, medium-coarse, coarse and ultra-coarse. As used in the specification of the present disclosure, the terms (I) "nano grade" is defined as a material having a particle size of less than about 0.2 μm, (II) "ultra-fine grade" is defined as a material having a particle size of about 0.2 μm to about 0.5 μm, (III) "submicron grade" is defined as a material having a particle size of about 0.5 μm to about 0.9 μm, (IV) "fine grade" is defined as a material having a particle size of about 1.0 μm to about 1.3 μm, (V) "medium-fine grade" is defined as a material having a particle size of about 1.4 μm to about 2.0 μm, (VI) "medium-coarse grade" is defined as a material having a particle size of about 2.1 μm to about 3.4 μm, (VII) "coarse grade" is defined as a material having a particle size of about 3.5 μm to about 5.0 μm, and (VIII) "ultra-coarse grade" is defined as a material having a particle size of more than about 5.0 μm.

[0051] As used herein, the term "hardmetal" generally refers to a metal matrix composite consisting of a ceramic hard phase embedded and fixed in the matrix by a ductile metal binder element, such as cobalt (i.e., the metal binder thus forms the metallic binder phase). Powders of the ceramic hard phase and metallic binder phase can be processed into a wide variety of microstructures that achieve different mechanical and physical properties. Additionally, additional components can be added to the composition to help control and improve the properties achieved by the hardmetal composition. By controlling various parameters including grain size, cobalt content, dotation (e.g., alloy carbides), and carbon content, hardmetal manufacturers can suitably tailor its performance to a particular application. Hardmetals are ideally designed to provide both the optimal physical properties of ceramics, such as heat resistance, hardness, and fracture toughness, and the optimal physical properties of metals, such as the ability to plastically deform. The naturally ductile metal binder serves to counteract the characteristic brittle behavior of the ceramic hard phase, thus enhancing its hardness, fracture toughness, and durability. The combination of excellent hardness and fracture toughness makes cemented carbides ideal candidates for applications involving significant wear, such as materials processing, tool inserts such as insert blanks, structural components, etc. The ceramic hard phase of a cemented carbide is typically composed of refractory carbides, borides, nitrides, or carbonitrides of metals from Groups 4, 5, and 6 of the Periodic Table, including, but not limited to, tungsten, titanium, niobium, tantalum, chromium, vanadium, molybdenum, zirconium, hafnium, or any desired combination thereof. The ceramic hard phase can be present in the powder in any possible combination with the above-mentioned metals, and in any weight amount consistent with the objectives of the present subject matter. To qualify as a cemented carbide in the specification of this disclosure, a cemented carbide generally has a ceramic hard phase composed of at least 60% by weight based on the total weight of the cemented carbide.

[0052] As used in the specification of this disclosure, the term "about" means plus or minus 5% of the numerical values ​​used in the claims and in this disclosure. Thus, "about" can be used to allow flexibility in the endpoints of a numerical range, and a given value may be "above" or "below" the given value. Thus, for example, a value of 50% can be expressed as, for example, 47.5% to 52.25%, 47.5% to 52.5%, 47.75% to 50%, 50% to 52.5%, 48% to 48.5%, 48% to 48.75%, 48% to 49%, 48% to 49.5%, 48% to 49.75%, 48% to 50%, 48% to 50.25%, 48% to 50.5%, 48% to 50.75%, 48% to 51%, 48% to 51.5%, 48% to 51.75%, 48% to 52%, 48% to 52.25%, 48% to 52.5% , 48.25%~48.5%, 48.25%~48.75%, 48.25%~49%, 48.25%~49.5%, 48.25%~49.75%, 48.25%~50%, 48.25%~50.25%, 48.25%~50.5%, 48.25%~50.75%, 48.25%~51%, 48.25%~51.25%, 48.25%~51.5%, 48.25%~51.75%, 48.25%~52%, 48.25%~52.25%, 48.25%~52.5%, 48.5%~48 .75%, 48.5%~49%, 48.5%~49.5%, 48.5%~49.75%, 48.5%~50%, 48.5%~50.25%, 48.5%~50.5%, 48.5%~50.75%, 48.5%~51%, 48.5%~51.25%, 48.5%~51.5%, 48.5%~51.75%, 48.5%~52%, 48.5%~52.25%, 48.5%~52.5%, 49%~49.25%, 49%~49.5%, 49%~49.75%, 49%~50%, 49%~5 0.25%, 49%~50.5%, 49%~50.75%, 49%~51%, 49%~51.25%, 49%~51.5%, 49%~51.75%, 49%~52%, 49%~52.25%, 49%~52.5%49.5%~49.75%, 49.5%~50%, 49.5%~50.25%, 49.5%~50.5%, 49.5%~50.75%, 49.5%~51%, 49.5%~51.5%, 49.5%~51.75%, 49.5%~52%, 49.5%~52.25%, 49.5%~52.5%, 49.75%~50%, 49.75%~50.25%, 49.75%~50.5%, 49.75%~50.75%, 49.75%~51%, 49.75%~51.25%, 49.75%~51.5%, 49.75%~51.75%, 49.75%~52%, 49.75%~52.25% , 49.75%-52.5%, 50%-50.25%, 50%-50.5%, 50%-50.75%, 50%-51%, 50%-51.25%, 50%-51.5%, 50%-52%, 50%-52.25%, 50%-52.5%, etc.

[0053] As used herein, the term "green body" refers to material in the form of a bound powder or plate before the material is physically sintered.

[0054] As used herein, "spherical" refers to particles having a substantially round shape.

[0055] As used throughout this disclosure, the term "generally" has the meaning of "usually," "in the vicinity of," or "within the vicinity of."

[0056] As used herein, the term "substantially" refers to the complete or nearly complete extent or degree of an action, property, characteristic, state, structure, item, or result.

[0057] As used herein, the term "apparent density" means g / cm 3The term "apparent density" refers to the mass per unit volume of the powder or particles of the cemented carbide in a loose state, expressed as 1 / 10 ...

[0058] As used herein, the term "free-flowing" refers to a loosely packed cemented carbide powder exhibiting pore space between each flowable particle of the cemented carbide powder without any physical restrictions or barriers that inhibit the flow of the particles of the cemented carbide powder.

[0059] As used herein, a "high density cemented carbide" refers to a material having a hardness of at least about 5 g / cm 3 ~Approx. 15g / cm 3 The present invention is intended to encompass cemented carbide powders having an apparent density in the range of

[0060] How to fabricate high density hardmetal for binder jet additive manufacturing The present disclosure is based on the concept of producing a dense hardmetal powder based on a ceramic hard phase powder and a metallic binder phase powder used for binder jetting, and then 3D printing it, generally by two sintering cycles. First, a first pre-sintering process step is performed to densify the RTP powder (i.e. composed of a mixture of ceramic hard phase powder and metallic binder phase powder). Then, this is followed by a second sintering process step to impart further densification and finally to obtain a printable powder with a full density where the particles of the hardmetal powder are no longer sintered together. The obtained fully densified printable powder can then be effectively utilized for binder jetting to 3D print objects.

[0061] As will be apparent to those skilled in the art, the desired particle size of the cemented carbide powder mixture, consisting of ceramic hard phase powder, metal binder phase powder and organic binder, can be achieved by a first grinding operation, usually under ambient conditions (i.e., in a ball mill, attritor mill or planetary mill at 25° C., 298.15 K and 101.325 kPa pressure) for several hours (e.g., 8, 16, 32, 64 hours) to obtain a slurry blend. In some embodiments, instead of using a ball mill, attritor mill or planetary mill as the physical machine, ultrasonic mixing may suitably be the blending method of choice. Thus, in this case, ultrasonic mixing uses acoustic energy to effectively process, for example, powders, pastes, liquids and combinations thereof with breakthrough speed, quality and reproducibility. Powders of almost any size, material properties or morphology are rapidly and thoroughly mixed using, for example, an acoustic mixer. Acoustic processing is often orders of magnitude faster than conventional techniques. Here, the acoustic mixer may employ, for example, a 60 Hz motion, which causes each particle to randomly collide with adjacent particles, divert its path, collide, and then re-collide with other particles with similar chaotic behavior. The main purpose of the blending operation is to promote good distribution of the metal binder and good wettability between the components of the slurry blend. Subjecting the cemented carbide mixture consisting of ceramic hard phase powder, metal binder phase powder, and organic binder to a grinding operation is key to enhancing the physical integrity of the ground cemented carbide powder mixture and possibly deagglomerating the tungsten carbide (WC) crystals. Acceptable distribution and good wettability quality of the metal binder are basic and essential parameters to obtain a cemented carbide blend with excellent physical quality. On the other hand, if the distribution and wettability quality of the metal binder phase are rather poor, this may result in the unnecessary formation of pores and cracks in the final sintered body, which is detrimental to the produced cemented carbide.

[0062] As will be appreciated by those skilled in the art, milling is carried out by first adding a grinding liquid to a batch of powder materials including ceramic hard phase powder, metal binder phase powder, and organic binder mixture to initially form a slurry composition. The grinding liquid may be, but is not limited to, water, alcohols such as ethanol, methanol, isopropanol, butanol, cyclohexanol, organic solvents such as heptane, hexane, acetone, or toluene, alcohol mixtures, alcohol and solvent mixtures, or any combination thereof. The properties of the slurry composition depend, among other things, on the amount of grinding liquid added. Because drying the slurry composition requires energy, it is ideal to minimize the amount of grinding liquid used to obtain the slurry composition to keep costs down. However, sufficient grinding liquid must be added to achieve a pumpable slurry composition and avoid clogging of the system. Additionally, other compounds commonly known to those skilled in the art, such as dispersants, pH adjusters, etc., may be added to the slurry composition. Non-limiting examples of organic binders may be polyethylene glycol (PG), paraffin, polyvinyl alcohol (PVA), long chain fatty acids, wax, or any combination thereof, and the amount added to the slurry composition before grinding is typically, for example, 15% to 25% by volume (i.e., the total volume % occupied by each of the above-mentioned components) based on the total volume of the formed slurry composition.

[0063] The milled slurry composition can then be spray dried, freeze dried, or vacuum dried as a slurry blend to granulate, for example, to effectively provide spherical, free-flowing powder agglomerates. Alternatively, the slurry blend can be vacuum dried to form an RTP powder.

[0064] In the case of spray drying, the slurry blend containing the powder material (i.e., having ceramic hard phase powder and metal binder phase powder) mixed with the organic liquid and the organic binder can be atomized through a suitable nozzle in a drying tower, where the small droplets are instantly dried by horizontally entering a hot gas stream, e.g., nitrogen, argon, or air stream, into the drying tower to form free-flowing, spherical RTP powder agglomerates. As used herein, "atomization" refers to the process in which the bulk liquid feedstock is converted into discrete droplets, greatly increasing the surface area of ​​the feedstock liquid, thereby greatly increasing the achievable evaporation rate of the solvent (i.e., the grinding liquid). The atomization stage is designed to create optimal conditions for the evaporation of the solvent from the slurry composition, resulting in an optimally dried RTP powder with the desired free-flowing properties. The spray is formed using a nozzle and a rotary atomizer. The drying tower may be equipped with only one nozzle or multiple nozzles to form free-flowing, spherical RTP powder agglomerates.

[0065] Next, the RTP powder, which typically has a particle size of less than about 63 microns, is sieved. A 200 mesh screen, which allows powders characterized by a particle size of less than about 74 microns to pass, may be suitably used for sieving. Those skilled in the art of producing high density carbide powders for 3D printing will know that the mesh number is inversely proportional to the particle size of the powder passing through the screen. That is, the larger the mesh number of the screen or sieve used, the smaller the particle size of the particles passing through the screen or sieve used. Thus, alternatively, in other examples, a 4 mesh screen, a 6 mesh screen, an 8 mesh screen, a 12 mesh screen, a 16 mesh screen, a 20 mesh screen, a 30 mesh screen, a 40 mesh screen, a 50 mesh screen, a 60 mesh screen, a 70 mesh screen, an 80 mesh screen, a 100 mesh screen, or a 140 mesh screen may be employed for sieving, which will allow powders characterized by a particle size of less than about 4760 microns, less than about 3360 microns, less than about 2380 microns, less than about 1680 microns, less than about 1190 microns, less than about 840 microns, less than about 590 microns, less than about 420 microns, less than about 297 microns, less than about 250 microns, less than about 210 microns, less than about 177 microns, less than about 149 microns, or less than about 105 microns to pass. Those skilled in the art will readily recognize various screening methods, non-limiting examples of such screening techniques include, but are not limited to, vibration screening, wet screening, horizontal screening, tap screening, and air jet screening.

[0066] The sieved RTP powder is then subjected to a pre-sintering heating procedure in a first cycle. The pre-sintering temperature in the first cycle can be generally from about 500°C to about 1250°C, from about 500°C to about 1275°C, from about 500°C to about 1300°C, from about 500°C to about 1325°C, from about 520°C to about 1250°C, from about 520°C to about 1275°C, from about 520°C to about 1300°C, from about 520°C to about 1325°C, from about 550°C to about 1250°C, from about 550°C to about 1275°C, from about 550°C to about 1300°C, or from about 550°C to about 1325°C. This is usually done in a reactive hydrogen (H2) atmosphere, with a hydrogen (H2) flow rate generally applied at about 1000 liters / hour to about 6000 liters / hour, about 2000 liters / hour to about 6000 liters / hour, about 3000 liters / hour to about 6000 liters / hour, about 4000 liters / hour to about 6000 liters / hour, or about 5000 liters / hour to about 6000 liters / hour. The temperature can usually be increased steadily, for example, at a rate of about 0.70°C / min. In some examples, the temperature can be increased sequentially, moving from a rate of about 2°C / min to about 10°C / min, or changing from a rate of about 2°C / min to about 5°C / min. Heating can be carried out in a sintering furnace for about 15 minutes to about 30 minutes, or about 30 minutes to about 45 minutes, at the highest temperature of a given temperature range. The particular type of heating pattern selected is carried out for a particular amount of time in a manner that imparts the desired phase transformation during the first pre-sintering cycle.

[0067] Generally, the first cycle pre-sintering heat-up procedure may be performed in a reactive hydrogen (H2) atmosphere, typically applying a hydrogen (H2) pressure of up to about 35 mbar. In some examples, the applied pressure of hydrogen (H2) ranges from about 5 mbar to about 35 mbar. In other examples, the applied pressure of hydrogen (H2) ranges from about 10 mbar to about 35 mbar. In still other examples, the applied pressure of hydrogen (H2) ranges from about 15 mbar to about 35 mbar. In still other examples, the applied pressure of hydrogen (H2) ranges from about 20 mbar to about 35 mbar. In yet other examples, the applied pressure of hydrogen (H2) ranges from about 25 mbar to about 35 mbar. Even in still other examples, the applied pressure of hydrogen (H2) ranges from about 30 mbar to about 35 mbar.

[0068] The applied pressure of hydrogen (H2) can also be in the range of about 5 mbar to about 10 mbar, about 10 mbar to about 15 mbar, about 15 mbar to about 20 mbar, about 5 mbar to about 20 mbar, about 5 mbar to about 25 mbar, about 5 mbar to about 27 mbar, about 5 mbar to about 30 mbar, about 5 mbar to about 32 mbar, about 15 mbar to about 25 mbar, about 20 mbar to about 25 mbar, about 20 mbar to about 27 mbar, about 20 mbar to about 30 mbar, about 20 mbar to about 32 mbar, about 22 mbar to about 30 mbar, about 25 mbar to about 30 mbar, about 27 mbar to about 30 mbar, about 27 mbar to about 32 mbar, or about 27 mbar to about 35 mbar.

[0069] The pre-sintered RTP powder of the first cycle then subsequently undergoes a sintering consolidation step of a second cycle to finally form a sintered printable powder, which is finally used for binder jetting to 3D print the object after undergoing a sieving operation. In general, the sintering consolidation step of the second cycle can be suitably carried out in an inert argon (Ar) atmosphere by suitably applying an argon (Ar) pressure of up to about 50 mbar, typically at a flow rate of about 30 liters / hour to about 300 liters / hour, at a flow rate of about 100 liters / hour to about 300 liters / hour, at a flow rate of about 150 liters / hour to about 300 liters / hour, at a flow rate of about 200 liters / hour to about 300 liters / hour, or at a flow rate of about 250 liters / hour to about 300 liters / hour. In some examples, the applied pressure of argon (Ar) ranges from about 10 mbar to about 50 mbar with argon (Ar). In other examples, the applied pressure of argon (Ar) ranges from about 15 mbar to about 50 mbar. In yet other examples, the applied pressure of argon (Ar) ranges from about 20 mbar to about 50 mbar. In yet other examples, the applied pressure of argon (Ar) ranges from about 25 mbar to about 50 mbar. Even still other examples, the applied pressure of argon (Ar) ranges from about 30 mbar to about 50 mbar. In yet other examples, the applied pressure of argon (Ar) ranges from about 35 mbar to about 50 mbar. In yet still other embodiments, the applied pressure of argon (Ar) ranges from about 40 mbar to about 50 mbar. Even still other embodiments, the applied pressure of argon (Ar) ranges from about 45 mbar to about 50 mbar.

[0070] The applied pressure of argon (Ar) may also be in the range of about 10 mbar to about 15 mbar, about 10 mbar to about 20 mbar, about 15 mbar to about 20 mbar, about 15 mbar to about 22 mbar, about 15 mbar to about 25 mbar, about 15 mbar to about 27 mbar, about 20 mbar to about 25 mbar, about 10 mbar to about 25 mbar, about 25 mbar to about 30 mbar, about 25 mbar to about 35 mbar, about 30 mbar to about 35 mbar, about 30 mbar to about 37 mbar, about 30 mbar to about 40 mbar, about 30 mbar to about 45 mbar, about 35 mbar to about 40 mbar, about 25 mbar to about 40 mbar, about 25 mbar to about 45 mbar, or about 40 mbar to about 45 mbar. The sintering temperature in the second cycle is usually applied at about 500°C and ends at about 1250°C, at about 500°C and ends at about 1275°C, at about 500°C and ends at about 1300°C, at about 500°C and ends at about 1325°C, at about 520°C and ends at about 1250°C, at about 520°C and ends at about 1275°C, at about 520°C and ends at about 1300°C, at about 520°C and ends at about 1325°C, at about 550°C and ends at about 1250°C, at about 550°C and ends at about 1275°C, at about 550°C and ends at about 1300°C, or at about 550°C and ends at about 1325°C. The particular sintering temperature range is selected to provide sufficient melting of the metallic binder phase. During this process, the metallic binder phase finally enters the liquid phase, while the carbide grains (i.e., have a much higher melting point) remain in the solid phase. At the sintering temperature, the metallic binder and the carbide grains form a eutectic liquid phase, in which the carbide grains are positioned and subsequently coated with the metallic binder. As a result of this process, the metallic binder embeds and solidifies the carbide particles, forming a metal matrix composite with characteristic material properties. The temperature can be increased steadily, typically at a rate of, for example, about 0.70° C. / min. In some examples, the temperature can be increased sequentially, switching from a rate of about 2° C. / min to about 10° C. / min, or transitioning from a rate of, for example, about 2° C. / min to about 5° C. / min.Heating can be maintained in the sintering furnace for about 15 minutes to about 30 minutes, or about 30 minutes to about 45 minutes, at the highest temperature of the given temperature range until the desired phase transformation occurs during the second sintering cycle, followed by a cooling step that typically reduces the temperature to about 25° C. over a period of about 2 hours.

[0071] Typically, the sintered printable powder, which has a particle size of about 25 microns, is then sieved. For sieving, a 400 mesh screen is preferably used, which allows powders characterized by a particle size of less than about 37 microns to pass through. Those skilled in the art of producing high density carbide powders for 3D printing will know that the mesh number is inversely proportional to the particle size of the powder passing through the screen. In other words, the higher the mesh number of the screen or sieve used, the smaller the particle size of the particles passing through the screen or sieve used. Thus, alternatively, in other examples, a 4 mesh screen, a 6 mesh screen, an 8 mesh screen, a 12 mesh screen, a 16 mesh screen, a 20 mesh screen, a 30 mesh screen, a 40 mesh screen, a 50 mesh screen, a 60 mesh screen, a 70 mesh screen, a 80 mesh screen, a 100 mesh screen, a 140 mesh screen, a 200 mesh screen, a 230 mesh screen, a 270 mesh screen, or a 325 mesh screen may be used for sieving. A sieving machine may be used that passes powders characterized by having a particle size of less than about 4760 microns, less than about 3360 microns, less than about 2380 microns, less than about 1680 microns, less than about 1190 microns, less than about 840 microns, less than about 590 microns, less than about 420 microns, less than about 297 microns, less than about 250 microns, less than about 210 microns, less than about 177 microns, less than about 149 microns, less than about 105 microns, less than about 74 microns, less than about 62 microns, less than about 53 microns, or less than about 44 microns, respectively. Those skilled in the art will readily recognize various sieving methods, non-limiting examples of such sieving techniques can include, but are not limited to, vibration sieving, wet sieving, horizontal sieving, tap sieving, and air jet sieving.

[0072] To determine the specific particle size of RTP and printable powders, a person skilled in the art will be able to easily familiarize himself with techniques employing either dynamic digital image analysis (DIA), static laser light scattering (SLS), also known as laser diffraction, or image analysis and visual measurement with an electron microscope, a technique known as light obscuration. Each method covers a characteristic size range that can be measured. These ranges partially overlap. However, the results of measuring the same sample can all be different, depending on the specific method used. A person skilled in the art who wishes to determine particle size or particle size distribution will be able to easily know how each of the mentioned methods is generally carried out and practiced. Thus, for example, the reader is referred to (i) "Dynamic Digital Image Analysis, Laser Diffraction, and Sieve Analysis," Recce Technology, Inc., and (ii) the scientific publication "Graphical Comparison of Image Analysis and Laser Diffraction Particle Size Distribution Data from Measurements of Non-Spherical Particle Systems," Kelly et al., AAPS Pharm Sci Tech. Aug. 18, 2006, Vol. 7(3), Article No. 69, for further insight into the procedures and methodologies, all of which are incorporated herein by reference in their entireties.

[0073] Manufacturing techniques contemplated herein for 3D printing include, but are not limited to, binder jetting, fused deposition modeling (FDM), material jetting, electron beam powder bed, or directed energy deposition, for example, as described in ASTM (American Society for Testing and Materials) Additive Manufacturing Technical Committee F-42.

[0074] Binder jetting can be used to 3D print a green body formed from sintered printable hardmetal powder. As described herein, the sintered printable hardmetal particles can be 3D printed into a green body by employing one or more ALM techniques. In theory, any ALM technique operable to convert the sintered printable hardmetal powder into a green body during 3D printing can be practically employed. In the binder jetting process, an electronic file is provided that details the design parameters of the green body. The binder jetting device spreads a first layer of sintered printable hardmetal powder into a build box. The print head then moves over the powder layer and deposits a liquid binder according to the specific design parameters for that specific layer. The formed layer is then dried and hardened, and the build box is lowered. A new specific layer of sintered printable hardmetal powder is spread over the previously formed and hardened layer according to the design parameters, and the process is repeated sequentially until finally the entire green body is 3D printed. In some embodiments, other 3D printing devices besides binder jetting can be used to print green bodies or green articles from the sintered printable cemented carbide powder.

[0075] The 3D printed green body is then typically heat cured in an oven for about 6 hours at a temperature starting at about 150° C. and ending at about 180° C., or starting at about 180° C. and ending at about 200° C. Here, the sole purpose of the heat curing is essentially to heat cure the organic binder, thereby strengthening and physically binding the 3D printed green body like an adhesive. Finally, following the heat curing, the 3D printed green body is then sintered at a temperature starting at about 1500° C. and ending at about 1560° C., or starting at about 1560° C. and ending at about 1600° C., completing the entire process of 3D printing an object by binder jetting.

[0076] Reference is now made to FIG. 1, which is a flow diagram illustrating all the process steps described above for producing high density cemented carbide powder for binder jetting to 3D print objects, in accordance with an exemplary embodiment of the present subject matter.

[0077] As shown in FIG. 1, in step 90, a slurry composition is first prepared, comprising ceramic hard phase powder, metal binder phase powder and organic binder in a grinding liquid, as described in paragraph ¶

[0062] . Then, in step 95, the slurry composition is ground to obtain a slurry blend, as described in paragraph ¶

[0061] , and then, in step 100, the slurry blend is spray-dried to form an RTP powder, as disclosed in paragraph ¶

[0063] -

[0064] . In step 105, the RTP powder is sieved, as disclosed in paragraph ¶

[0065] , and then, in step 107, the RTP powder is pre-sintered in a first cycle to densify the RTP powder, as disclosed in paragraph ¶

[0066] -

[0068] . The pre-sintered RTP powder is then sintered in a second cycle in step 110 to form a more densified printable powder, as described in paragraphs ¶

[0069] -

[0070] . After sieving the formed printable powder in step 115 as disclosed in paragraphs ¶

[0071] , the formed printable powder is subjected to binder jetting in step 120 to 3D print a green body, as disclosed in paragraphs ¶

[0073] -

[0074] . The process then finally ends by thermally curing the 3D printed green body in step 125 as disclosed in paragraph ¶

[0075] , and sintering the thermally cured 3D printed green body in step 130 as described in paragraph ¶

[0075] to finally form a 3D object.

[0078] The ceramic hard phase is preferably composed of hard metals, generally carbides, borides, nitrides and / or carbonitrides, but may most typically be present in the RTP powders composed of tungsten carbide. In some examples, the ceramic hard phase of the cemented carbide composition is composed of at least one metal carbide, boride, nitride or carbonitride selected from, for example, groups IVB, VB and VIB of the periodic table, or any desired combination thereof. In certain embodiments, the ceramic hard phase is composed of at least one of carbides, borides, nitrides or carbonitrides of tungsten, titanium, tantalum, niobium, vanadium, zirconium, molybdenum, chromium or hafnium, or any desired combination thereof. In certain other specific embodiments, the ceramic hard phase is comprised of tungsten carbide, tantalum carbide, niobium carbide, vanadium carbide, molybdenum carbide, chromium carbide, zirconium carbide, hafnium carbide, titanium carbide, niobium carbide, or any desired combination thereof. The ceramic hard phases, including the metal carbides, borides, nitrides, or carbonitrides mentioned above, may be incorporated in any combination consistent with and compatible with the objectives of the present subject matter.

[0079] The ceramic hard phase may typically be present in the RTP powder at about 60% to about 95% by weight, based on the total weight of the cemented carbide. In some examples, the ceramic hard phase is present at about 65% to about 95% by weight, based on the total weight of the cemented carbide. In other examples, the ceramic hard phase is present at about 70% to about 95% by weight, based on the total weight of the cemented carbide. In still other examples, the ceramic hard phase is present at about 75% to about 95% by weight, based on the total weight of the cemented carbide. In still other examples, the ceramic hard phase is present at about 80% to about 95% by weight, based on the total weight of the cemented carbide. In yet other examples, the ceramic hard phase is present at about 85% to about 95% by weight, based on the total weight of the cemented carbide. In even still other examples, the ceramic hard phase is present at about 90% to about 95% by weight, based on the total weight of the cemented carbide.

[0080] The ceramic hard phase may also be present in the RTP powder in an amount of about 60% by weight to about 65% by weight, about 60% by weight to about 70% by weight, about 65% by weight to about 70% by weight, about 65% by weight to about 75% by weight, about 70% by weight to about 75% by weight, about 60% by weight to about 75% by weight, about 60% by weight to about 80% by weight, about 62% by weight to about 80% by weight, about 65% by weight to about 80% by weight, about 67% by weight to about 80% by weight, about 70% by weight to about 80% by weight, about 75% by weight to about 80% by weight, about 60% by weight to about 85% by weight, about 65% by weight to about 85% by weight, about 67% by weight to about 85% by weight, about 70% by weight to about 85% by weight, about It may be present at 75% by weight to about 85% by weight, about 80% by weight to about 85% by weight, about 60% by weight to about 90% by weight, about 65% by weight to about 90% by weight, about 67% by weight to about 90% by weight, about 70% by weight to about 90% by weight, about 75% by weight to about 90% by weight, about 77% by weight to about 90% by weight, about 80% by weight to about 90% by weight, about 85% by weight to about 90% by weight, about 60% by weight to about 92% by weight, about 65% by weight to about 92% by weight, about 67% by weight to about 92% by weight, about 70% by weight to about 92% by weight, about 75% by weight to about 92% by weight, about 77% by weight to about 92% by weight, about 80% by weight to about 92% by weight, or about 85% by weight to about 92% by weight.

[0081] The RTP powder may further suitably include at least one or more metal binders.

[0082] The metal binder may typically be cobalt. In some embodiments, the metal binder may include one or more transition metals, ideally from group VIIIB of the periodic table. In some embodiments, the metal binder may also be a cobalt-based alloy. The cobalt-based metal alloy binder may include a cobalt-transition metal alloy in some other specific embodiments. For example, the transition metal of the cobalt-based metal alloy binder may be suitably selected from one or more of molybdenum, ruthenium, rhenium, rhodium, platinum, palladium, manganese, copper, iron, nickel, or any desired combination thereof. In other embodiments, transition metals including at least one of molybdenum, ruthenium, rhenium, rhodium, platinum, palladium, manganese, copper, iron, nickel, or any desired combination thereof may be used without cobalt. In yet other examples, the metal binder may further include a metalloid such as silicon, and / or may include aluminum.

[0083] The metal binder may be present in the RTP powder in any amount consistent with the objectives and principles of the present disclosure. The metal binder may generally be present in the RTP powder in an amount of about 1% to about 30% by weight, based on the total weight of the hardmetal. In some examples, the metal binder is present in the RTP powder in an amount of about 1% to about 3% by weight, based on the total weight of the hardmetal. In other examples, the metal binder is present in the RTP powder in an amount of about 1% to about 5% by weight, based on the total weight of the hardmetal. In still other examples, the metal binder is present in the RTP powder in an amount of about 1% to about 7% by weight, based on the total weight of the hardmetal. In still other examples, the metal binder is present in the RTP powder in an amount of about 1% to about 10% by weight, based on the total weight of the hardmetal. In yet other examples, the metal binder is present in the RTP powder in an amount of about 1% to about 15% by weight, based on the total weight of the hardmetal. In yet other examples, the metal binder is present in the RTP powder in an amount of about 1% to about 20% by weight, based on the total weight of the cemented carbide. In still other embodiments, the metal binder is present in the RTP powder in an amount of about 1% to about 25% by weight, based on the total weight of the cemented carbide. In still other embodiments, the metal binder is present in the RTP powder in an amount of about 1% to about 27% by weight, based on the total weight of the cemented carbide.

[0084] The metal binder may be, based on the total weight of the cemented carbide, about 1 weight % to about 2 weight %, about 2 weight % to about 5 weight %, about 5 weight % to about 7 weight %, about 3 weight % to about 7 weight %, about 7 weight % to about 10 weight %, about 10.1 weight %, about 10.2 weight %, about 10.3 weight %, about 10.4 weight %, about 10.5 weight %, about 10.6 weight %, about 10.7 weight %, about 10.8 weight %, about 10.9 weight %, about 7 weight % to about 13 weight %, about 7 weight % to about 15 weight %, about 7 weight % to about 17 weight %, about 7 weight % to about 20 weight %, about 7 weight % to about 22 weight %, about 7 weight % to about 25 weight %, about 7 weight % to about 27 weight %, about 7 weight % to about 3 ... It may be present in the RTP powder in an amount of 0 wt%, about 10 wt% to about 13 wt%, about 10 wt% to about 15 wt%, about 10 wt% to about 17 wt%, about 10 wt% to about 20 wt%, about 10 wt% to about 22 wt%, about 10 wt% to about 25 wt%, about 15 wt% to about 20 wt%, about 15 wt% to about 22 wt%, about 15 wt% to about 25 wt%, about 15 wt% to about 27 wt%, about 10 wt% to about 30 wt%, about 15 wt% to about 30 wt%, about 17 wt% to about 30 wt%, about 20 wt% to about 30 wt%, about 22 wt% to about 30 wt%, about 25 wt% to about 30 wt%, or about 27 wt% to about 30 wt%.

[0085] The processed RTP powders and printable powders disclosed in this application each have a density of at least about 5 g / cm 3 ~Approx. 15g / cm 3 In some examples, the apparent density of the processed RTP powder and printable powder can range from about 7 g / cm 3 ~Approx. 15g / cm 3 In other examples, the apparent density of the processed RTP powder and printable powder is at least about 10 g / cm 3 ~Approx. 15g / cm 3 In yet another example, the apparent density of the processed RTP powder and printable powder is at least about 12 g / cm 3 ~Approx. 15g / cm 3 In yet another embodiment, the apparent density of the processed RTP powder and printable powder is at least about 14 g / cm 3 ~Approx. 15g / cm3 is in the range.

[0086] The apparent density of the processed RTP powder and printable powder is also at least about 5 g / cm 3 ~about 6g / cm 3 , at least about 5 g / cm 3 ~Approx. 7g / cm 3 , at least about 5 g / cm 3 ~about 8g / cm 3 , at least about 5 g / cm 3 ~About 9g / cm 3 , at least about 5 g / cm 3 ~Approx. 10g / cm 3 , at least about 5 g / cm 3 ~Approx. 11g / cm 3 , at least about 5 g / cm 3 ~Approx. 12g / cm 3 , at least about 5 g / cm 3 ~Approx. 13g / cm 3 , at least about 5 g / cm 3 ~Approx. 14g / cm 3 , 6g / cm 3 ~Approx. 7g / cm 3 , at least about 6 g / cm 3 ~about 8g / cm 3 , at least about 6 g / cm 3 ~About 9g / cm 3 , at least about 6 g / cm 3 ~Approx. 10g / cm 3 , at least about 6 g / cm 3 ~Approx. 11g / cm 3 , at least about 6 g / cm 3 ~Approx. 12g / cm 3 , at least about 6 g / cm 3 ~Approx. 13g / cm 3 , at least about 6 g / cm 3 ~Approx. 14g / cm 3 , at least about 6 g / cm 3 ~Approx. 15g / cm 3 , at least about 7 g / cm 3 ~about 8g / cm 3 , at least about 7 g / cm 3 ~About 9g / cm 3 , at least about 7 g / cm3 ~Approx. 10g / cm 3 , at least about 7 g / cm 3 ~Approx. 11g / cm 3 , at least about 7 g / cm 3 ~Approx. 12g / cm 3 , at least about 7 g / cm 3 ~Approx. 13g / cm 3 , at least about 7 g / cm 3 ~Approx. 14g / cm 3 , at least about 8 g / cm 3 ~About 9g / cm 3 , at least about 8 g / cm 3 ~Approx. 10g / cm 3 , at least about 8 g / cm 3 ~Approx. 11g / cm 3 , at least about 8 g / cm 3 ~Approx. 12g / cm 3 , at least about 8 g / cm 3 ~Approx. 13g / cm 3 , at least about 8 g / cm 3 ~Approx. 14g / cm 3 , at least about 8 g / cm 3 ~Approx. 15g / cm 3 , at least about 9 g / cm 3 ~Approx. 10g / cm 3 , at least about 9 g / cm 3 ~Approx. 11g / cm 3 , at least about 9 g / cm 3 ~Approx. 12g / cm 3 , at least about 9 g / cm 3 ~Approx. 13g / cm 3 , at least about 9 g / cm 3 ~Approx. 14g / cm 3 , at least about 9 g / cm 3 ~Approx. 15g / cm 3 , at least about 10 g / cm 3 ~Approx. 11g / cm 3 , at least about 10 g / cm 3 ~Approx. 12g / cm 3 , at least about 10 g / cm 3 ~Approx. 13g / cm 3 , at least about 10 g / cm 3 ~Approx. 14g / cm 3, at least about 11 g / cm 3 ~Approx. 12g / cm 3 , at least about 11 g / cm 3 ~Approx. 13g / cm 3 , at least about 11 g / cm 3 ~Approx. 14g / cm 3 , or at least about 11 g / cm 3 ~Approx. 15g / cm 3 , at least about 12 g / cm 3 ~Approx. 13g / cm 3 , at least about 12 g / cm 3 ~Approx. 14g / cm 3 , at least about 13 g / cm 3 ~Approx. 14g / cm 3 , or at least about 13 g / cm 3 ~Approx. 15g / cm 3 , may be in the range.

[0087] The yield of the formed printable powder can typically be about 60% to about 90%, or at least 90%. In some examples, the yield of the formed printable powder is about 70% to about 90%. In other examples, the yield of the formed printable powder is about 80% to about 90%. In still other examples, the yield of the formed printable powder is about 85% to about 90%. Even in still other examples, the yield of the formed printable powder is at least 90%.

[0088] The yield of the printable powder formed may also be about 60% to about 65%, about 60% to about 70%, about 60% to about 75%, about 60% to about 80%, about 60% to about 85%, about 65% to about 70%, about 65% to about 75%, about 65% to about 80%, about 65% to about 85%, about 65% to about 90%, about 70% to about 75%, about 70% to about 80%, about 70% to about 85%, about 75% to about 80%, about 75% to about 85%, about 75% to about 90%, or about 80% to about 85%. EXAMPLES

[0089] The following examples are provided to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the described subject matter, and are not intended to limit the scope of what the inventors regard as their disclosure, nor are they intended to represent that the following experiments are all or the only experiments performed. Efforts have been made to ensure accuracy with respect to the numbers used, but some experimental error and deviation should be accounted for.

[0090] Example 1 Printable powders exhibit higher apparent density than pre-sintered RTP powders [Table 1] TIFF2025513840000001.tif41170

[0091] The apparent density of the high density cemented carbide powder for binder jetting to 3D print objects according to an exemplary embodiment of the present subject matter was measured after different processing steps. First, the apparent density of the RTP powder formed after spray drying the slurry blend was measured. Then, the apparent density of the pre-sintered RTP powder in the first cycle was obtained. Finally, the apparent density of the sintered RTP powder in the second cycle was obtained. To achieve the above, the RTP powder having a particle size of less than about 63 microns was sieved using a 200 mesh screen. The apparent density of the RTP powder was obtained. Then, in order to increase the density and further maintain the round spherical morphology of the RTP powder particles, the RTP powder was pre-sintered in the first cycle at about 1250° C. for about 30 minutes using a zirconia crucible in a furnace. To break up the remaining agglomerates, the RTP powder was ground by milling in an attritor mill for about 30 minutes. The milled RTP powder was then sieved through a 200 mesh screen to remove the remaining agglomerates, and the apparent density was measured. The RTP powder was then sintered in a second cycle at about 1250°C for about 30 minutes to increase the apparent density and form a printable powder. The formed printable powder was then ground in an attritor mill for about 30 minutes to break up any remaining agglomerates and grind the printable powder. The ground printable powder having a particle size of about 25 microns was then sieved through a 400 mesh screen to remove any agglomerates present, maintain the desired particle size, and measure the apparent density. Finally, the resulting fully densified printable powder can then be used for binder jetting to 3D print objects. The results obtained are shown in Table 1. As can be seen, Table 1 demonstrates that the apparent density increased with each increasing number of sintering cycles. The apparent density of the unsintered RTP powder was 3.27 g / cm. 3 When the RTP powder was presintered in the first cycle, the presintering procedure of the RTP powder resulted in an apparent density of 3.27 g / cm 3 from 5.25 g / cm 3 The RTP powder was sintered in a second cycle to form the final fully densified printable powder, increasing the apparent density to 5.25 g / cm. 3from 5.45 g / cm 3 The apparent density increased by about 3.8%.

[0092] While the present disclosure has been described with reference to embodiments thereof, it will be understood by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without departing from the spirit and scope of the present disclosure as defined in the appended claims.

[0093] With respect to the use of substantially any plural and / or singular terms herein, those of skill in the art can convert from plural to singular and / or from singular to plural as appropriate to the context and / or application. The various singular / plural permutations are not expressly set forth herein for the sake of clarity.

[0094] The subject matter described herein may also depict different components that are included within or connected to other different components. It should be understood that the architectures depicted are merely exemplary, and that in fact many other architectures that achieve the same functionality may be implemented. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Thus, in this specification, any two components that combine to achieve a particular functionality may be considered to be "associated" with each other such that the desired functionality is achieved, regardless of the architecture or intermediate components. Similarly, any two components that are associated in this manner may also be considered to be "operably connected" or "operably coupled" with each other to achieve the desired functionality, and any two components that may be associated in this manner may also be considered to be "operably coupled" with each other to achieve the desired functionality. Specific examples of operably coupleable include, but are not limited to, physically matable and / or physically interacting components, and / or wirelessly interacting and / or wirelessly interacting components, and / or logically interacting and / or logically interacting components.

[0095] One or more components may be referred to herein as being "configured to," "configurable to," "operable / to operate," "adapted / compatible," "capable," "compatible / compatible to," etc. Those skilled in the art will recognize that such terms (e.g., "configured to") can generally encompass active and / or inactive and / or standby components, unless the context requires otherwise.

[0096] While particular aspects of the subject matter described herein have been shown and described, it will be apparent to one skilled in the art that, based on the teachings herein, changes and modifications can be made without departing from the subject matter described herein and its broader aspects, and therefore, the appended claims encompass within their scope all such changes and modifications that are within the true spirit and scope of the subject matter described herein. In general, it will be understood by those skilled in the art that the terms used in this specification, and particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," and the term "comprising" should be interpreted as "including but not limited to").

[0097] Those skilled in the art will further appreciate that where a particular numerical recitation of an introduced claim is intended, such intent will be expressly recited in the claim, and in the absence of such recitation, no such intent exists. For example, as an aid to understanding, the following appended claims may include the use of the introductory phrases "at least one" and "one or more" to introduce the claim recitation. However, the use of such phrases should not be construed as meaning that the introduction of a claim recitation with the indefinite article "a" or "an" limits any particular claim containing such an introduced claim recitation to a claim containing only one such recitation, even if the same claim contains the introductory phrases "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should normally be interpreted as meaning "at least one" or "one or more"), and the same applies to the use of definite articles used to introduce claim recitations.

[0098] Moreover, even if a claim recitation explicitly recites specific numerical values ​​introduced, one of ordinary skill in the art will recognize that such recitations should generally be interpreted to mean at least the recited numerical values ​​(e.g., the bare recitation "two recitations" without other modifiers generally means at least two recitations, or more than two recitations).

[0099] Furthermore, when a convention similar to "at least one of A, B, and C, etc." is used, such a configuration is generally intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B and C together, etc.). When a convention similar to "at least one of A, B, or C, etc." is used, such a configuration is generally intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B and C together, etc.). Those skilled in the art will further appreciate that disjunctive words and / or phrases presenting two or more alternative terms, whether in this specification, claims, or drawings, should typically be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms, unless the context dictates otherwise. For example, the phrase "A or B" is typically understood to include the possibilities of "A" or "B" or "A and B."

[0100] With respect to the appended claims, those skilled in the art will appreciate that the operations described therein may generally be performed in any order. Also, while various operational flows are shown in a sequential order, it will be understood that various operations may be performed in orders other than those shown, or may be performed simultaneously. Examples of such alternative orderings may include overlapping, interleaving, interrupting, reordering, incremental, preparatory, supplementary, simultaneous, reverse, or other variant orderings, unless the context dictates otherwise. Moreover, terms such as "responsive to," "related to," or other past tense adjectives are generally not intended to exclude such variants, unless the context dictates otherwise.

[0101] Those skilled in the art will appreciate that the specific exemplary processes and / or apparatus and / or techniques described above are representative of more general processes and / or apparatus and / or techniques that are taught elsewhere herein, e.g., in the claims filed herewith and / or elsewhere in this application.

[0102] While various aspects and embodiments are disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are intended to be illustrative and not limiting, with the true scope and spirit being indicated by the following claims.

[0103] The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting, as other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein.

[0104] Where a range of values ​​is provided, unless the context clearly dictates otherwise, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limits of that range, and any other stated or intervening value in that stated range, is included in the disclosure. The upper and lower limits of those narrower ranges that may be independently included in the narrower ranges are also encompassed within the disclosure, but may be modified to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure.

[0105] Those skilled in the art will recognize that the components (e.g., operations), devices, objects, and the accompanying discussion described herein are used as examples for conceptual clarity, and that various configuration variations are contemplated. Thus, as used herein, the specific examples described and the accompanying discussion are intended to be representative of their more general classes. In general, the use of any specific exemplar is intended to be representative of its class, and should not be construed as a limitation to not including the specific components (e.g., operations), devices, and objects.

[0106] Further, for example, any sequences and / or temporal orders of sequences of the systems and methods described herein are illustrative and should not be construed as limiting in nature. Thus, while process steps may be shown and described in a sequence or temporal order, it should be understood that they are not necessarily limited to being performed in a particular order or temporal order. For example, steps in such processes or methods may generally be performed in a variety of different sequences and orders while still falling within the scope of the present disclosure.

[0107] Finally, the publications and / or patents discussed herein are provided solely for their disclosure prior to the filing date of the described disclosure, and nothing herein should be construed as an admission that the described disclosure is not entitled to antedate such publication by virtue of prior disclosure.

Claims

1. 1. A method for manufacturing a three-dimensional (3D) object, comprising: preparing a slurry composition in a grinding liquid comprising a ceramic hard phase powder, a metal binder phase powder and an organic binder; milling the slurry composition to form a slurry blend; spray drying the slurry blend to obtain an RTP powder; sieving the RTP powder; pre-sintering the RTP powder in a first cycle to densify the RTP powder; sintering the pre-sintered RTP powder in a second cycle to form a more densified printable powder; and sieving the printable powder; subjecting the printable powder to binder jetting to 3D print a green body; curing the 3D printed green body; Sintering the hardened 3D printed green body to form a 3D object. The method includes:

2. The method for manufacturing a three-dimensional (3D) object of claim 1 , wherein the RTP powder is free-flowing.

3. 2. The method of claim 1, wherein the pre-sintering in the first cycle is performed at a temperature starting at about 550°C and ending at about 1250°C.

4. 4. The method for manufacturing a three-dimensional (3D) object according to claim 3, wherein the pre-sintering in the first cycle is carried out in an atmosphere having a hydrogen pressure of up to about 35 mbar applied with a hydrogen flow of up to about 6000 liters / hour.

5. The method for manufacturing a three-dimensional (3D) object according to claim 3, wherein the pre-sintering in the first cycle is carried out for about 15 minutes to about 30 minutes.

6. The method for manufacturing a three-dimensional (3D) object according to claim 3, wherein the pre-sintering in the first cycle is carried out for about 30 minutes to about 45 minutes.

7. 10. The method of claim 1, wherein the sintering in the second cycle is performed at a temperature starting at about 550°C and ending at about 1250°C.

8. 8. The method for manufacturing a three-dimensional (3D) object according to claim 7, wherein the second cycle sintering is carried out in an atmosphere having an argon pressure of up to about 50 mbar applied with an argon flow of up to about 300 liters / hour.

9. The method for manufacturing a three-dimensional (3D) object according to claim 7, wherein the sintering in the second cycle is carried out for about 15 minutes to about 30 minutes.

10. The method of manufacturing a three-dimensional (3D) object according to claim 7, wherein the sintering in the second cycle is carried out for about 30 minutes to about 45 minutes.

11. 10. The method of claim 1, wherein the yield of the formed printable powder is between about 60% and about 90%.

12. 12. The method of claim 11, wherein the yield of the formed printable powder is between about 70% and about 90%.

13. 13. The method of claim 12, wherein the yield of the formed printable powder is about 80% to about 90%.

14. 14. The method of claim 13, wherein the yield of the formed printable powder is about 85% to about 90%.

15. 15. The method for manufacturing a three-dimensional (3D) object of claim 14, wherein the yield of the formed printable powder is at least 90%.

16. The apparent density of the RTP powder and the printable powder is at least about 5 g / cm ３ ~Approx. 15g / cm ３ 2. The method of claim 1, wherein the thickness of the three-dimensional (3D) object is in the range of

17. The ceramic hard phase is selected from tungsten carbide (WC), titanium carbide (TiC), tantalum carbide (TaC), niobium carbide (NbC), vanadium carbide (VC), zirconium carbide (ZrC), molybdenum carbide (Mo ２ 2. The method of claim 1 , further comprising one or more of: SiO 2 (SiO 3 ) (C) or Hafnium Carbide (HfC), or any combination thereof.

18. 20. The method of manufacturing a three-dimensional (3D) object according to claim 17, wherein the ceramic hard phase comprises WC.

19. 10. The method of manufacturing a three-dimensional (3D) object according to claim 1, wherein the metal binder phase powder comprises cobalt.

20. 10. The method of manufacturing a three-dimensional (3D) object of claim 1, wherein the RTP powder is sieved through a 4 mesh screen, a 6 mesh screen, an 8 mesh screen, a 12 mesh screen, a 16 mesh screen, a 20 mesh screen, a 30 mesh screen, a 40 mesh screen, a 50 mesh screen, a 60 mesh screen, a 70 mesh screen, an 80 mesh screen, a 100 mesh screen, a 140 mesh screen, or a 200 mesh screen.

21. 10. The method of manufacturing a three-dimensional (3D) object of claim 1, wherein the printable powder is sieved through a 4 mesh screen, a 6 mesh screen, an 8 mesh screen, a 12 mesh screen, a 16 mesh screen, a 20 mesh screen, a 30 mesh screen, a 40 mesh screen, a 50 mesh screen, a 60 mesh screen, a 70 mesh screen, an 80 mesh screen, a 100 mesh screen, a 140 mesh screen, a 200 mesh screen, a 230 mesh screen, a 270 mesh screen, a 325 mesh screen, or a 400 mesh screen.

22. 10. The method of claim 1, wherein curing the 3D printed green body is performed at a temperature starting at about 150°C and ending at about 180°C.

23. 10. The method of claim 1, wherein curing the 3D printed green body is performed at a temperature starting at about 180°C and ending at about 200°C.

24. 23. The method of claim 22, wherein curing the 3D printed green body is performed for up to about 6 hours.

25. 10. The method of claim 1, wherein sintering the hardened 3D printed green body is performed at a temperature starting at 1500°C and ending at about 1560°C.

26. 10. The method of claim 1, wherein sintering the hardened 3D printed green body is performed at a temperature starting at 1560°C and ending at about 1600°C.

27. 10. The method of manufacturing a three-dimensional (3D) object of claim 1, wherein the printable powder is fully densified.

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