Complex-phase synergistic ultra-dispersion black body carbonized metal ceramic coating as well as preparation method and application thereof

Abstract

The invention provides a complex-phase synergistic ultra-dispersion black body carbonized metal ceramic coating as well as a preparation method and application thereof, and belongs to the technical field of coating materials. The complex-phase synergistic ultra-dispersion black body carbonized metal ceramic coating is composed of silicon carbide, boron carbide, titanium carbide, carbon nanotubes, graphene and carbides thereof and various heat-resistant element materials, has the advantages of strong dispersivity, high blackness, high melting point, high strength and good thermal conductivity, is an advanced synergistic ultra-dispersion black body carbonized ceramic material, and can be widely applied to the field of metal ceramic materials. The composite material has excellent thermal stability, wear resistance and corrosion resistance, and effectively solves the comprehensive technical problems of wear and corrosion prevention and high heat conduction and efficiency improvement of the surface layers of heating surface matrixes of boilers such as pulverized coal furnaces, circulating fluidized bed boilers and biomass garbage incinerators through the targeted and reasonable design of functional materials. When being applied to the heated surface treatment of the boiler, the heat resistance can be reduced, abrasion and corrosion can be prevented, the service life of the boiler can be prolonged, and energy conservation and emission reduction are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of coating materials, and particularly relates to a multiphase synergistic ultra-dispersed black body carbide metal ceramic coating, a preparation method thereof, and an application thereof. Background Art

[0002] A boiler is an important energy conversion device and is widely used in various industries such as electric power, heating, petrochemical, chemical, steel, non-ferrous metals, etc. Therefore, the service life and performance of boilers are crucial for the development of these industries. During the manufacturing process of boiler steel parts, internal stresses will be generated, such as thermal stress, cold working stress, chemical reaction stress, load stress, structural change stress, etc., which will have an important impact on their performance and service life.

[0003] In high-temperature components such as boiler steel pipes in thermal power plants, when using pearlitic heat-resistant steels without chromium such as low-carbon steel and low-carbon molybdenum steel, due to the decomposition of cementite in the pearlite to produce graphite, a reaction of Fe3C - 3Fe + C(graphite) occurs, and graphitization will occur over time. The first step of graphitization is the spheroidization of pearlite, and graphitization is the final result of the decomposition of carbides in steel under long-term high-temperature action. Graphitization will cause the steel to become brittle, reducing strength, plasticity, and impact toughness. The cementite in the steel will decompose into free carbon and form graphite crystal inclusions in the steel.

[0004] Regarding the graphitization of low-carbon boiler steel, under the long-term action of working temperature and stress of steel parts, carbides will decompose into free graphite. This process occurs spontaneously and is called the graphitization process of P heat-resistant steel. Graphitization not only eliminates the role of carbides but also causes a significant reduction in the strength and plasticity of steel parts, resulting in possible brittle fracture of steel parts. The principle of graphitization is through thermal activation, converting thermodynamically unstable carbon atoms from a turbostratic structure into a graphite crystal structure. Therefore, during the graphitization process, it is necessary to promote the atomic rearrangement and structural transformation. Here, a solution of a multiphase synergistic ultra-dispersed black body carbide metal ceramic coating, a preparation method thereof, and an application thereof is provided.

[0005] In addition, during the processing of boiler steel metal materials, internal stresses will be generated due to reasons such as processing deformation and friction. Due to the physical inhomogeneity of metal materials, such as grain size, composition, etc., internal stresses will also exist. Temperature change: The change in temperature during processes such as hot working or cold working of materials will also generate internal stresses.

[0006] The maximum normal stress occurs on the surface, and the maximum shear stress occurs at a certain distance from the surface. Under the influence of alternating stress, cracks are easily nucleated in these parts and extend to the surface to cause peeling. If there is sliding contact of ash flow against the wall in addition to the rolling friction contact of flue gas particles, the damage position will gradually move to the surface. This is because the maximum shear stress occurs on the surface during pure sliding. Due to the oxidation roughness of the steel surface, uneven materials, inclusions, microcracks and hard spots, the location of fatigue damage will change, so some cracks start from the surface, while some start from the sub-surface.

[0007] Wear of metal materials mainly occurs in the deformation and fracture process of the surface. Improving the strength and toughness of the surface of the component that bears the friction can improve the wear resistance. For adhesive wear, improving lubrication conditions, improving the bonding ability of the oxide film and the base metal to enhance the stability of the oxide film, preventing direct contact between metals, and reducing surface roughness can reduce adhesive wear. The typical characteristics of fatigue wear are pits of different depths and sizes on the surface of steel parts, or large-scale surface peeling, referred to as pitting or peeling. There are also dislocation outcrops inside the crystal.

[0008] Pitting cracks usually start from the surface, expand inwards, and finally the secondary cracks bend towards the surface. The material above the crack breaks off and falls off to form pitting. The surface morphology of a single pitting pit is often fan-shaped. Spalling cracks generally originate from deeper layers inside the subsurface. Wear is a surface phenomenon that occurs on objects. Anti-corrosion and anti-wear are important measures to ensure the safe and efficient operation of boilers. Anti-corrosion treatment is mainly to prevent the heating surface from corrosion due to high temperature, high pressure and corrosive media, and to extend the service life of the boiler. Anti-wear treatment is to reduce the wear of the heating surface caused by factors such as particle wear, high temperature oxidation and thermal fatigue, and to ensure the thermal efficiency and safe operation of the boiler.

[0009] In a carbon-containing medium environment, such as the flue gas produced by the combustion of pulverized coal, carburization will increase the surface hardness of the material, but it will also reduce the toughness and fatigue resistance of the material. In the boiler heating surface, excessive carburization may cause uneven material properties, thereby affecting the safe operation and life of the equipment. Therefore, surface protection measures are needed to reduce the impact of excessive carburization on the boiler heating surface. On the one hand, an appropriate amount of cementite can improve the hardness, wear resistance and fatigue resistance of steel. This is because cementite has a high hardness and can effectively resist external loads and wear. On the other hand, excessive cementite may cause steel to become brittle and reduce its plasticity and toughness. This is because too much cementite will cause the internal structure of the steel to become uneven, making the steel prone to fracture when subjected to force.

[0010] The discovery, preparation and application of two-dimensional graphene structures have broken the classical theory that "thermodynamic fluctuations do not allow any two-dimensional crystals to exist at a finite temperature", opening a new era of two-dimensional material applications. Stable graphene has excellent high temperature resistance, electrical conductivity and thermal conductivity. However, graphene only contains one element of carbon, and the van der Waals force between layers is weak, which limits its application to a certain extent. Carbon-based carbon / carbon (C / C) composites with carbon nanotube fibers and graphene fibers as reinforcements are a new type of high-performance structural and functional composite materials. Its fully interpenetrated cross-linked carbon structure not only retains the excellent mechanical properties and flexible structural designability of fiber-reinforced materials, but also has many advantages of carbon materials, such as low density, low thermal expansion coefficient, high thermal conductivity and electrical conductivity, excellent thermal shock resistance, ablation resistance and friction resistance, etc. More importantly, the mechanical properties of this material increase instead of decrease with increasing temperature, and it has excellent characteristics such as high strength, high modulus, high fracture toughness, high thermal conductivity, excellent thermal insulation and low density.

[0011] At present, the original black body enhanced protection ceramic material coating technology products are applied to graphite crystals to increase blackness and zirconium oxide for wear protection. However, such a design has a single functionality. Due to the limited vertical thermal conductivity and high temperature resistance of graphite crystals and the high thermal barrier performance of zirconium oxide, it cannot effectively strain its alternating stress expansion deformation for a long time, and the products produced cannot meet the long-term safe operation requirements of the boiler heating surface. In addition, climate issues are an important issue of concern to the international community today. With the promotion and implementation of the dual carbon goals, the country has proactively arranged large-scale power generation facilities to ensure energy security, and its low-carbon, carbon reduction, and carbon fixation are major issues for efficient and safe operation and maintenance. Therefore, overcoming and solving the stress and fatigue problems of metal materials under the action of alternating external forces during manufacturing and later loads, such as crystal dislocation slip and twin defects, extending the service life of boilers, reducing maintenance costs, improving energy efficiency, solving the comprehensive technical problems of anti-wear and corrosion protection and high thermal conductivity and efficiency, and saving energy and reducing emissions are crucial to the development of various industries such as electricity, heating, petrochemicals, chemicals, steel, and non-ferrous metals.

[0012] The present invention studies and understands the failure mechanism of boiler steel within its service life, proactively discovers and eliminates defects in the early stages and effectively handles them. It provides a measure for upgrading the process production and application technology of blackening, purification, anti-wear and anti-corrosion coating materials on the inner wall of the boiler heating surface to reduce energy consumption and prevent carbon and ash deposition, and provides a safer and more effective high-temperature field protection application solution. Summary of the invention

[0013] The object of the present invention is to provide a composite-phase synergistic ultra-dispersed black-body carbide cermet coating, its preparation method and application. The prepared composite-phase synergistic ultra-dispersed black-body carbide cermet coating is applied to the surface treatment of boilers, and the energy-saving transformation of boiler blackening is an optimization and upgrade of the existing boiler system, which can significantly improve the heat exchange efficiency of the boiler heating surface, greatly improve the long-term safe operation efficiency and thermal energy utilization rate of the boiler, effectively reduce the thermal resistance, prevent wear and corrosion, and extend the service life of the boiler. It is of great significance for reducing pollutant emissions, effectively reducing energy consumption, and reducing the impact on the environment. While saving energy and reducing emissions, it also improves the economic benefits of enterprises.

[0014] In order to achieve the above-mentioned invention object, the present invention provides the following technical solutions:

[0015] The present invention provides a preparation method of a composite-phase synergistic ultra-dispersed black-body carbide cermet coating, including the following steps:

[0016] (1) Preparation of sol precursor mixed solution 1: Using ferric chloride solution as a eutectic catalyst, adding it to sodium silicate solution, catalyzing the reaction, and mixing and dispersing to obtain sol precursor mixed solution 1;

[0017] (2) Preparation of mixed solution 2: Adding silicon carbide, silicon nitride, and alumina to the mixed solution 1 in step (1), and uniformly mixing and coordinating to obtain mixed solution 2;

[0018] (3) Preparation of mixed solution 3: Adding tungsten, nano-diamond, titanium carbide, and boron nitride to the mixed solution 2 and fully mixing, dispersing, and coordinating to obtain mixed solution 3;

[0019] (4) Preparation of component A: Adding carbon nanotubes, boron nitride, and rare earth to the mixed solution 3 and mixing, dispersing, and coordinating to obtain component A;

[0020] (5) Preparation of component B: Adding isopropanol, nitrogen, and a homogeneous solution mixture of two-dimensional graphene to the sol precursor mixed solution 1, and mixing, dispersing, and coordinating to obtain component B;

[0021] (6) Stirring and mixing the component A and component B solutions fully and uniformly to obtain a composite-phase synergistic ultra-dispersed black-body carbide cermet coating.

[0022] Preferably, in step (1), the modulus of the sodium silicate solution ≧ 3.5, the concentration of the ferric chloride solution is 40-60%; the volume ratio of the sodium silicate solution to the ferric chloride solution is 680-760:10-30; the mixing and dispersing time ≧ 3 hours, and the temperature is 20-30 °C.

[0023] Preferably, in step (2), the volume-mass ratio of the miscible solution 1 to silicon carbide, silicon nitride, and alumina is 680 - 760 mL: 100 - 150 g: 100 - 150 g: 150 - 200 g; the mixing and coordination time is ≥ 2 hours, and the temperature is 20 - 30 °C.

[0024] Preferably, in step (3), the volume-mass ratio of the miscible solution 2 to tungsten, nanodiamond, titanium carbide, and boron nitride is 680 - 760 mL: 10 - 30 g: 10 - 30 g: 30 - 50 g: 10 - 30 g; the mixing and dispersion time is ≥ 2 hours, and the temperature is 20 - 30 °C.

[0025] Preferably, in step (4), the volume-mass ratio of the miscible solution 3 to carbon nanotubes, boron nitride, and rare earth is 680 - 760 mL: 10 - 30 g: 10 - 30 g: 10 - 15 g; the mixing and dispersion time is ≥ 2 hours, and the temperature is 20 - 30 °C.

[0026] Preferably, in step (5), the volume-mass ratio of the miscible solution 1 to isopropanol solution, nitrogen, and two-dimensional graphene is 680 - 760 mL: 100 - 300 g: 100 - 300 g: 50 - 150 g; the mixing and dispersion time is ≥ 2 hours, and the temperature is 20 - 30 °C.

[0027] Preferably, in step (6), the volume ratio of the A and B component solutions is 510 - 570: 170 - 190.

[0028] The present invention also provides a composite phase synergistic ultra-dispersed blackbody carbide cermet coating prepared by the preparation method of the above composite phase synergistic ultra-dispersed blackbody carbide cermet coating.

[0029] The present invention also provides an application of the composite phase synergistic ultra-dispersed blackbody carbide cermet coating prepared by the preparation method of the above composite phase synergistic ultra-dispersed blackbody carbide cermet coating as a boiler coating material.

[0030] Preferably, the method of the application is to mix the composite phase synergistic ultra-dispersed blackbody carbide cermet coating with a curing agent evenly and then spray it onto the inner surface of the boiler, and gradually sinter and cure with the increase of the furnace temperature to obtain a composite phase synergistic ultra-dispersed blackbody carbide cermet coating;

[0031] The volume-mass ratio of the composite phase synergistic ultra-dispersed blackbody carbide cermet coating to the curing agent is 680 - 760 mL: 30 - 50 g.

[0032] The beneficial effects of the present invention compared with the prior art are:

[0033] (1) The composite-phase synergistic ultra-dispersed blackbody carbide cermet coating of the present invention is composed of silicon carbide, boron carbide, titanium carbide, carbon nanotubes, graphene and its carbides together with various heat-resistant element materials. It has strong dispersibility, high blackness, high melting point, high strength and good thermal conductivity. It is an advanced synergistic ultra-dispersed blackbody carbide ceramic material. Through precise proportioning, the materials in this system interact synergistically through covalent bonds, ionic bonds, metal bonds and van der Waals forces among multi-electron atoms and molecules. For example, in metal-organic frameworks, metal nodes are connected to organic ligands through covalent bonds and ionic bonds, and are combined by van der Waals forces between layers. The materials in this system form a diverse complex system through inorganic coordination, surface functional group modification and organic-inorganic hybridization, etc., with good miscibility at high temperatures, strong binding force, excellent thermal stability, abrasion resistance and corrosion resistance. Through targeted and reasonable design of the constituent functional materials, the comprehensive technical problems of anti-abrasion and anti-corrosion protection and high thermal conductivity enhancement of the matrix surface layer of the heating surface of boilers such as pulverized coal boilers, circulating fluidized bed boilers, and biomass waste incinerators are effectively solved. Applying it to the treatment of the boiler heating surface can reduce thermal resistance, prevent wear and corrosion, extend the service life of the boiler, and contribute to energy conservation and emission reduction.

[0034] (2) The composite-phase synergistic ultra-dispersed blackbody carbide cermet coating of the present invention applies carbon and nitrogen active dispersion technology to diffuse and disperse carbon and nitrogen compounds in the coordination body of ceramic nanocrystalline materials into the boiler steel matrix and defects, improving problems such as stress and fatigue of metal materials under the action of alternating external forces during manufacturing and later loading (such as crystal dislocation slip and twin defects). It is of great significance for preventing and optimizing the formation of early defects and cracks in boiler steel, such as preventing irreversible hydrogen embrittlement caused by the infiltration and accumulation of hydrogen atoms.

[0035] The composite-phase synergistic ultra-dispersed blackbody carbide cermet coating of the present invention is different from traditional carburizing and nitriding technologies. It is based on surface treatment through internal interface dispersion and external interface protection of the matrix to form a protective coating. Metal carbide particles are evenly dispersed in the ceramic matrix. Through liquid-phase dispersion and diffusion, carbon and nitrogen doping dispersion C / C modifies the layered two-dimensional graphite crystals of the matrix layer, forming fine-grained second-phase particles in the steel to block dislocation slip. After high-temperature sintering, ceramic fibers are formed, enhancing the strength and toughness of the material. Among them, transition metals such as tungsten, iron, titanium carbide, and alumina form atomic cluster compounds, which have a close-packed hexagonal crystal system. Their infinite solid solubility improves thermal stability and has high plasticity and variability. It is an anti-metal fatigue material and provides an effective solution for repairing damaged defects during the load operation of boiler steel, thus greatly extending the safe operation cycle of the boiler.

[0036] By precisely controlling the size, shape, and distribution of carbide particles, the mechanical and thermal properties of the duplex synergistic ultra-dispersed black-body carbide cermet coating have been further optimized, endowing it with extremely high hard and tough phases and good thermal stability, enabling it to withstand extreme working environments. In practical applications, this application of the ultra-dispersed carbide black-body synergistic ceramic material protection technology can be applied to various industrial boilers and household boilers, extending the service life of the boilers, reducing maintenance costs, and improving energy efficiency. To ensure its long-term stable, efficient, and safe operation for specific requirements.

[0037] (3) The application of nano-scale low-dimensional materials, whose microcrystalline micro-size effect constructs a long-range disordered and multi-isotropic material structure, improving the material's properties. This material has excellent high-temperature resistance (can withstand high temperatures up to 3000 degrees Celsius), wear resistance, corrosion resistance, and photoconductive properties. Due to its radiation characteristics, the thermal radiation conversion rate per unit time is the highest, or the conversion time per unit heat is the shortest. The full conversion of thermal energy improves the thermal efficiency, prevents the flue gas outlet temperature from being too high, and thus has broad application prospects in the protection and enhancement of boiler equipment in the industrial field. By coating the inner wall surface of the boiler heating surface with this radiation-absorbing dispersed carbide ceramic material, its radiation heat transfer ability can be enhanced, improving the boiler thermal efficiency. It improves the anti-abrasion and anti-corrosion performance of the heating surface and provides a solution for high-temperature field protection with efficient heat absorption and heat transfer.

[0038] The multi-phase synergistic ultra-dispersed black-body carbide cermet coating of the present invention is isotropic due to its composition design. According to the particle radiation theory, when energy photons pass through an isotropic medium, the direction of light is the same as the direction of the wave vector, showing a linear relationship. The Poynting vector of the black body exhibits diffuse scattering characteristics, maintaining and enhancing the radiation characteristics of the conduction and radiation heat transfer wall surfaces in the original boiler design, and greatly improving the conduction and radiation heat transfer efficiency. Due to the stability of the uniform replication of the product and the uniform color display characteristics after sintering, its color display effect can be used to judge the overheated part of the boiler steel matrix, innovatively providing the possibility for timely pre-judgment and maintenance. The carbon-based black body of the present invention has an obvious thermal radiation effect at any given temperature, and its radiation ability is the strongest, being called a complete radiator to distinguish it from other color system materials. The principle is that the maximum characteristic of black body radiation is that it will radiate the maximum amount of electromagnetic waves at a specific temperature and wavelength. Research shows that for radiant heat flux, for example, a pair of parallel flat walls with temperatures of 300K and 500K respectively; another pair of parallel flat walls with temperatures of 1000K and 1200K. At this time, the difference in the fourth power of the temperature of the first pair of flat walls is (T1 / 100)4-(T2 / 100)4 = 544K4, while that of the second pair of flat walls is 10736K4. If the system emissivities of the two pairs of flat walls are the same and the areas are also the same, although the temperature difference between the two pairs of flat walls is 200 degrees, the radiant heat flux at high temperature is almost 20 times larger than that at low temperature. This shows that radiant heat flux plays an important role in the high-temperature operation of the boiler, and radiation heat transfer is very important in the heat transfer process. In addition, the plasticity of intermetallic compounds is closely related to the strength of the bonding directionality. Here, the light scattering, due to its isotropic mechanism when photons pass through the matrix crystal, in the microscopic environment of the high-temperature light field, through the interaction with the electrons of the atoms in the solid solution crystal, weakens the bonding directionality and thus increases the plasticity of the solid crystal, effectively solving the inherent brittleness of ceramic-based materials and improving the strength and toughness.

[0039] (4) Preparation of the precursor miscible solution 1 of the product of the present invention, generating silicate colloids and their compounds iron silicate and sodium chloride, and participating in subsequent complexation reactions, with relatively high high-temperature corrosion resistance and adhesion properties. Among them, using the synthesized ferric chloride solution as a eutectic catalyst, the trivalent iron ions in ferric chloride and the silicate ions in sodium silicate undergo a double displacement reaction, and the generated heat energy and kinetic energy promote the diffusion of the chemical potential gradient, generating the high-temperature stable and corrosion-resistant compound iron silicate and sodium chloride. This specific complexation color reaction makes the color of the miscible solution 1 show a dark brownish red. This is because the iron ions in iron silicate are in the trivalent state and have relatively high oxidizing properties. Iron silicate has extremely low optical rotation and a relatively dark color, providing the possibility to detect local overheating phenomena by finding color differences through appearance during later detection, which is of great significance. The formation of iron silicate also indicates that this reaction has a relatively high reaction rate and reactivity, thus accelerating the reaction process. Its catalytic effect further neutralizes the reaction, balances the acid-base conjugate relationship, and provides the initial conformation of an important complex compound with acid-base corrosion resistance.

[0040] The generated sodium chloride is a stable inorganic salt. In the complex, it is used as a low-concentration ligand and applies its porous structure solid melting and cycling characteristics. Its high-temperature resistance characteristics are a high temperature of 801 °C, and the decomposition temperature is as high as 8000 °C. As a phase change material in the high-temperature environment of the boiler application working condition, its stable physical and chemical characteristics improve the plasticity of the coating structure. Among them, the chlorine element plays an anti-chlorine corrosion function because the nucleons of the same element have the same binding effect on electrons and do not produce electron reactions, providing a good solution for chlorine corrosion.

[0041] For chlorine corrosion in a high-temperature environment, when the concentration threshold of sodium chloride in the complex ligand of the product is relatively low, it can reduce the metal electrode potential difference and make it in a relatively balanced state. This is beneficial for preventing metal corrosion because the occurrence of corrosion requires a certain potential difference. As a silicate passivator, it has a good anti-corrosion effect by forming a protective film on the metal surface and has high chemical stability. At this time, sodium chloride is a corrosion inhibitor. Sodium chloride is used as an anti-permeation agent in the high-temperature ceramic coordination binding system to prevent oxidation. Due to its different reaction characteristics with chlorine, it can effectively prevent chlorine corrosion in a high-temperature environment. At high temperatures, the silicon component in the ceramic coating is the main bonding phase with silicon. In the ceramic coating with a multi-ligand ceramic phase dispersed distribution, the silicon component tension can effectively promote the interfacial bonding between the coating and the substrate and effectively prevent the influence of alternating loads on the bonding force. On the basis of pre-treating the substrate, using the composite phase synergistic ultra-dispersed black body carbide metal ceramic coating of the present invention to protect the substrate and sintering at high temperature and normal pressure, a composite phase ultra-dispersed carbide black body composite metal ceramic coating with a dense structure, no cracks and firmly bonded to the substrate can be prepared.

[0042] (5) The present invention adopts the concept method of combining sol-gel co-assembly and sintering, that is, by premixing and prefabricating the homogeneous coordination sol solutions of component A and component B. After use, the activity of the liquid-phase coordination particles is first catalytically dispersed to the defective parts and the surface layer of the matrix, and the whole naturally solidifies into a gel state. Its high temperature resistance enables it to be rapidly heated and sintered into a composite metal ceramic body. The products prepared by the sol-gel co-assembly method have good reproducibility. And due to the influence of competitive coordination in the miscible body, for the optimization of the energy potential surface, self-assembly occurs with the time effects of rapid stability, quasi-stability and relative steady state. And by removing the precipitates, unnecessary ratios at the microscale are avoided. Here, the influences of volume and temperature on the coordination reaction are fully considered. The macroscopic products obtained in this way, through the important complexation catalytic initial conformation, have reasonable molecular orbital stability with the synergistic interaction of multi-element nucleon electrons. It embodies the scientific idea that materials determine structure and structure determines properties. The composite phase synergistic ultra-dispersed blackbody carbide metal ceramic coating of the present invention is applied to the surface treatment of boilers, with strong bonding force, improving the heat exchange efficiency of the boiler heating surface, enhancing the safe operation efficiency and heat energy utilization rate of the boiler, reducing the thermal resistance, preventing wear and corrosion, prolonging the service life of the boiler, and contributing to energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0044] Figure 1 is the crystal structure of the cementite crystal (Fe 3 C) of the present invention;

[0045] Figure 2 is a long-distance photo of the high-temperature sintered coating prepared after spraying the composite phase synergistic ultra-dispersed blackbody carbide metal ceramic coating of the present invention on the boiler;

[0046] Figure 3 is a close-up photo of the high-temperature sintered coating prepared after spraying the composite phase synergistic ultra-dispersed blackbody carbide metal ceramic coating of the present invention on the boiler. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention.

[0048] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0049] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0050] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are merely exemplary.

[0051] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0052] The present invention provides a method for preparing a multiphase synergistic super-dispersed black body carbide cermet coating, comprising the following steps:

[0053] (1) Preparation of sol precursor mixture 1: Using the synthesized ferric chloride solution as a eutectic catalyst, adding a catalytic reaction to the sodium silicate solution, and mixing and dispersing to obtain sol precursor mixture 1;

[0054] Synthesizing ferric chloride (FeCl 3 ) solution and a solution with a sodium silicate modulus ≥ 3.5 can form a complex. The formation of this complex is based on the interaction between the iron ions (Fe 1 ) in ferric chloride, the silicate phase ions (SiO), and the hydroxide ions. The iron ions have empty orbitals and can accept the lone pair electrons from the silicate ions or other ligands to form coordination bonds. At the same time, the silicate ions are partially hydrolyzed to produce silicic acid and hydroxide ions, where silicic acid (H 2 SiOs) or different forms of silicate ions (such as HSiO 3 , SiO 3 2-etc.) further coordinate with iron ions. The complex formed by ferric chloride and silicate ions contains iron ions, silicate ions, and hydroxide ions. The "ferric chloride-sodium silicate complex" or "FeCI 3 -NazSiO 3 complex" is a complex mixture that can contain various coordination forms. Through a catalytic reaction, ferric chloride and sodium silicate form a complex containing iron ions, silicate ions, hydroxide ions, and water molecules, providing a complex carrier solution with good bonding properties for coordinating other functional materials.

[0055] (2) Preparation of miscible solution 2: Add silicon carbide, silicon nitride, and alumina to the sol miscible solution 1 in step (1), and mix and coordinate uniformly to obtain miscible solution 2, that is, Al 2 O 3 -SiC-C-Fe. Aluminum-silicon-carbon-iron system high-temperature resistant material.

[0056] The high-silica solution sodium silicate and sodium chloride interfaces in the later sintered solid solution mainly contribute to toughness improvement. The polymer filler silicon carbide is a third-generation semiconductor material with a hexagonal crystal structure, having properties such as wide energy levels, high breakdown electric fields, high thermal conductivity, and high saturated electron migration velocities. Among them, the corundum crystal structure of the polymer filler alumina is a hexagonal closest-packed structure with good insulation and high symmetry. It is a good conductor of electricity and heat. At high temperatures, through the reaction of iron with silicon carbide and alumina, and then with the original Fe 3 Si in the refractory material melts to form a silicon-rich phase Fe-Si-melt. Part of the Si in the silicon-rich phase generates silicon carbide under the action of carbon, which mainly bears the hard phase.

[0057] (3) Preparation of miscible solution 3: Add tungsten, nano-diamond, titanium carbide, and boron nitride to miscible solution 2 and mix and disperse uniformly to obtain miscible solution 3.

[0058] According to this grading, the hard phases in the miscible solution all have high thermal conductivity, heat resistance, wear resistance, and stability characteristics at this time. It is an ideal material to replace the traditional thermal barrier material zirconia in terms of anti-wear. The coordination compound composed of complex ions or complex molecules is called a complex (sometimes the complex ion is also called a complex, and there is no strict distinction between the two). The composition of a complex is generally divided into two parts: the inner sphere and the outer sphere. The part composed of the central ion and the ligand is called the inner sphere of the complex, and in the chemical formula of the complex, the inner sphere is generally represented by square brackets, and the part outside the square brackets is the outer sphere. For example, [Fe 3 (SiO 4 2- )], [Al(OH) 4 - 、H 4 [SiW 12 O 40 ​] etc. The central ion is the core part of the complex. It is located in the center of the complex ion. Most of them are ions with positive charges that are easy to lose outer electrons (tungsten, titanium, iron, aluminum metal ions) and ions (or molecules) complexed with the central ion as ligands. The non-metallic coordinating atoms in the ligand that provide free electron pairs are C, N, and B, and they are combined with the central ion in the complex ion by coordination bonds.

[0059] (4) Preparation of component A: adding carbon nanotubes, boron nitride and rare earth to the mixed solution 3 and dispersing and grading them to obtain component A;

[0060] Among them, the mixed solution 3 with various coordination forms is added with high temperature resistant one-dimensional materials carbon nanotubes, boron nitride and rare earth for further mixing, dispersion and uniform gradation, forming component A containing one-dimensional materials of C, B, N and multi-ligand complex as main carriers.

[0061] (5) Preparation of component B: adding isopropanol, nitrogen, and a two-dimensional graphene homogeneous solution mixed system to the sol precursor mixed solution 1, mixing, dispersing, and grading to obtain component B;

[0062] In this step, the nitrogen-carbon doping technique premixes the solution containing both the nitrogen source and the carbon source to obtain preliminary nitrogen-doped graphene. In the later stage, the performance of the nitrogen-doped graphene is further improved by mixing and dispersing with the component A and sintering at high temperature. Nitrogen-doped graphene with a small-size structure has high potential due to its special structure. Its graphene-nitrogen is a relatively active catalyst in the redox reaction, which enhances the adsorption and reduction of ligand molecules, and further characterizes and improves its physical and chemical properties. The oxidation activity of boron and nitrogen-doped graphene increases, which shows that using nitrogen-doped graphene as a matrix and adding other materials through physical and chemical doping to improve performance is also an important development direction.

[0063] (6) The solutions of component A and component B are fully stirred and mixed to obtain a uniformly graded composite phase enhanced super-dispersed black body carbonized metal ceramic coating.

[0064] When making the coating, the solutions of component A and component B are fully stirred and mixed evenly for grading. The ligand further diffuses evenly due to chemical potential and concentration gradient. It has an amorphous structure, and its atoms, ions or molecules are not arranged periodically, and its physical properties do not show regularity. Because its atomic arrangement is disordered, a long-range disordered microcrystalline structure is formed in all directions, and its physical properties must be isotropic. Thus, a super-dispersion high-temperature resistant black-body carbonized ceramic coating with super-dispersion characteristics is prepared. The component A and component B of the coating product are further fully stirred and mixed evenly with the curing agent aluminum tripolyphosphate, and sprayed onto the surface of the pretreated substrate. At this time, the diffusion characteristics of the active carbon, nitrogen and boron elements in the solution are obvious, and they are further dispersed and catalyzed in the melt, and diffuse in the matrix interface layer. Among them, the alloy matrix is subjected to dispersion treatment, and a composite-phase synergistic super-dispersion black-body carbonized metal ceramic coating is obtained by heating and sintering. It is recommended to use it up within 0.5 - 2 hours. After heating to form a solid solution, the hard phase and the tough phase in the structure interact with each other, providing a surface protection function. The functional coating formed after sintering reasonably protects the substrate and plays an important role in high-efficiency heat conduction and preventing excessive carburization and nitriding.

[0065] Among them, after isopropyl alcohol and sodium silicate are mixed and combined, a chemical reaction will occur to produce a new chemical substance, namely isopropyl silicate. Its synergistic effect improves the thermal stability and chemical inertness of the material. As a miscible material intermediate, it can significantly enhance the bonding ability of the material. The structural formula of isopropyl silicate is as follows:

[0066]

[0067] Through the active super-dispersion characteristics of carbon, nitrogen and boron elements in the liquid phase and the condensation sintering process, the one-dimensional carbon nanotubes and the two-dimensional graphene C element diffuse and dissolve into a C / C structure. The metal and carbide in the ligand diffuse and penetrate into the matrix and the surface layer synergistically, constructing an alternately distributed microstructure of strong interfaces (inorganic microcrystalline isotropic ceramic interfaces) and weak interfaces (transition metal atom cluster interfaces). The strong interface provides high load transfer ability, while the weak interface significantly improves the toughness of the material through crack guiding and energy absorption mechanisms. After sintering, it is the eutectic microstructure commonly found in metal materials, which is a solid phase with a special microstructure.

[0068] When making the coating with the coating of this product, the component A and component B of the coating are fully mixed and evenly dispersed with the curing agent aluminum tripolyphosphate. Based on the chemical properties and reaction characteristics of the curing agent aluminum tripolyphosphate, a stable α-ALPO is formed by reacting with the solid solution sodium silicate 4 , which does not melt at high temperature to form a colloid. During the curing and bonding process of aluminum tripolyphosphate with the coating carrier complex, a stable network structure is formed. Its P-N (phosphorus-nitrogen) bond multi-dentate ligand structure improves the catalytic activity, further enhances the coating stability, and strengthens the physical and chemical properties of the coating.

[0069] After the coating of the super-dispersed high-temperature resistant black-body carbonized ceramic coating is completed, pay attention to waterproofing. When heating up and sintering in the furnace, a high black-body radiation heat transfer capacity and an efficient anti-wear and anti-corrosion coating can be obtained.

[0070] Example 1

[0071] Example 1 of the present invention provides a preparation method of a multiphase synergistic super-dispersed black-body carbonized metal ceramic, and the specific steps are as follows:

[0072] (1) Preparation of sol precursor mixed solution 1: Using a synthetic 50% ferric chloride solution as a eutectic catalyst, add it to a sodium silicate solution with a modulus of 3.5 (Huai'an Pengli Industry and Trade Co., Ltd.), carry out a catalytic reaction, and mix and disperse at 25 °C for 3 hours to obtain sol precursor mixed solution 1. The volume ratio of the sodium silicate solution to the synthetic ferric chloride solution is 720 mL: 20 mL;

[0073] (2) Preparation of mixed solution 2: Add silicon carbide, silicon nitride, and alumina to the mixed solution 1 in step (1), and mix and coordinate and grade at 25 °C for 3 hours to obtain mixed solution 2. The volume-mass ratio of the sol mixed solution 1 to silicon carbide, silicon nitride, and alumina is 720 mL: 125 g: 125 g: 175 g;

[0074] (3) Preparation of mixed melt 3: Add tungsten, nano-diamond, titanium carbide, and boron nitride to the mixed solution 2, and mix and disperse and grade at 25 °C for 3 hours to obtain mixed solution 3. The volume-mass ratio of the mixed solution 2 to tungsten, nano-diamond, titanium carbide, and boron nitride is 720 mL: 20 g: 20 g: 40 g: 20 g;

[0075] (4) Preparation of component A: Add carbon nanotubes, boron nitride, and rare earth to the mixed solution 3, and mix and disperse and grade at 25 °C for 3 hours to obtain component A. The volume-mass ratio of the mixed solution 3 to carbon nanotubes, boron nitride, and rare earth is 720 mL: 20 g: 20 g: 12.5 g;

[0076] (5) Preparation of component B: Add isopropyl alcohol, nitrogen, and a homogeneous solution mixed system of two-dimensional graphene to the sol precursor mixed solution 1, mix and disperse and grade, and mix and disperse and grade at 25 °C for 3 hours to obtain component B; wherein the volume-mass ratio of the sol precursor mixed solution 1 to the isopropyl alcohol solution (Jiangsu Huayongxi Technology Co., Ltd., graphene isopropyl alcohol dispersion, 88%), urea, and two-dimensional graphene is 720 mL: 200 g: 200 g: 100 g;

[0077] (6) During use, mix the component A and component B solutions evenly according to a volume ratio of 540 mL: 180 mL, and grade to obtain a multiphase synergistic super-dispersed black-body carbonized metal ceramic coating.

[0078] (7) Preparation of the coating: The A and B components of the coating product are further thoroughly stirred and mixed with 40 g of the curing agent aluminum tripolyphosphate, and then sprayed onto the surface of the pretreated substrate. After heating and sintering, a composite phase synergistic ultra-dispersed blackbody carbide metal ceramic coating is obtained.

[0079] Thus, a composite phase synergistic ultra-dispersed blackbody carbide metal ceramic coating is prepared, and the specific appearance performance values are as follows:

[0080] 1. Appearance: High blackness liquid

[0081] 2. Specific gravity: 0.9 - 1.0

[0082] 3. PH: 5 - 7

[0083] 4. Viscosity: <100 mPa·s

[0084] 5. Surface drying time: <1 hour

[0085] 6. Complete curing time: 5 - 7 days

[0086] The high-temperature sintered coating prepared from this composite phase synergistic ultra-dispersed blackbody carbide metal ceramic coating ( Figure 2 、 3 ), and the specific performance values are as follows:

[0087] 1. Temperature resistance: Coating temperature resistance: ≥1450 °C

[0088] 2. High-temperature oxidation resistance: 6.35 mg / cm² (oxidized at 750 °C for 250 hours)

[0089] 3. The coating has excellent thermal shock resistance. When heated to 1450 °C or above (including 1450 °C) and quenched with cold water at least 10 times, it does not crack or peel off, or at least one major overhaul cycle.

[0090] 4. The coating has excellent high-temperature wear resistance and steam erosion resistance, which is more than 2 times that of the base material of the heated surface to be sprayed.

[0091] 5. Coating emissivity ≥0.95

[0092] 6. Pencil hardness: 6H

[0093] 7. Bonding strength: ≥15 Mpa

[0094] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a multi-phase synergistic superdispersed black body carbonized metal ceramic coating, characterized in that: The steps include: (1) Preparation of sol precursor mixed solution 1: using ferric chloride solution as a low eutectic catalyst, adding it to sodium silicate solution, catalyzing reaction, mixing and dispersing to obtain sol precursor mixed solution 1; (2) Preparation of mixed solution 2: adding silicon carbide, silicon nitride and aluminum oxide to the mixed solution 1 of step (1), uniformly mixing and grading to obtain mixed solution 2; (3) Preparation of mixed solution 3: adding tungsten, nano-diamond, titanium carbide and boron nitride to mixed solution 2, and fully mixing, dispersing and grading to obtain mixed solution 3; (4) Preparation of component A: adding carbon nanotubes, boron nitride and rare earth to the mixed solution 3 and dispersing and grading them to obtain component A; (5) Preparation of component B: adding isopropanol, nitrogen, and a two-dimensional graphene homogeneous solution mixed system to the sol precursor mixed solution 1, mixing, dispersing, and grading to obtain component B; (6) The solutions of component A and component B are fully stirred and mixed to obtain a composite phase enhanced super dispersed black body carbonized metal ceramic coating.

2. The method for preparing the multi-phase synergistic superdispersed black body carbonized metal ceramic coating according to claim 1, characterized in that: In step (1), the modulus of the sodium silicate solution is ≥3.5, the concentration of the ferric chloride solution is 40-60%; the volume ratio of the sodium silicate solution to the ferric chloride solution is 680-760:10-30; the mixing and dispersing time is ≥3 hours, and the temperature is 20-30°C.

3. The method for preparing the multi-phase synergistic superdispersed black body carbonized metal ceramic coating according to claim 1, characterized in that: In step (2), the volume mass ratio of the mixed solution 1 to silicon carbide, silicon nitride and aluminum oxide is 680-760 mL: 100-150 g: 100-150 g: 150-200 g; the mixing coordination time is ≧2 hours, and the temperature is 20-30°C.

4. The method for preparing the multi-phase synergistic superdispersed black body carbonized metal ceramic coating according to claim 1, characterized in that: In step (3), the volume mass ratio of the mixed solution 2 to tungsten, nano-diamond, titanium carbide and boron nitride is 680-760 mL: 10-30 g: 10-30 g: 30-50 g: 10-30 g; the mixing and dispersion time is ≧2 hours, and the temperature is 20-30°C.

5. The method for preparing the multi-phase synergistic superdispersed black body carbonized metal ceramic coating according to claim 1, characterized in that: In step (4), the volume mass ratio of the mixed solution 3 to the carbon nanotubes, boron nitride and rare earth is 680-760 mL: 10-30 g: 10-30 g: 10-15 g; the mixing and dispersion time is ≧2 hours, and the temperature is 20-30°C.

6. The method for preparing the multi-phase synergistic superdispersed black body carbonized metal ceramic coating according to claim 1, characterized in that: In step (5), the volume mass ratio of the mixed solution 1 to the isopropanol solution, nitrogen, and two-dimensional graphene is 680-760 mL: 100-300 g: 100-300 g: 50-150 g; the mixing and dispersing time is ≧2 hours, and the temperature is 20-30°C.

7. The method for preparing the multi-phase synergistic superdispersed black body carbonized metal ceramic coating according to claim 1, characterized in that: In step (6), the volume ratio of the component A and component B solutions is 510-570:170-190.

8. A complex phase synergistic superdispersed black body carbide metal ceramic coating prepared by the method for preparing a complex phase synergistic superdispersed black body carbide metal ceramic coating as claimed in any one of claims 1 to 7.

9. Use of the complex phase enhancement superdispersed black body carbide metal ceramic coating prepared by the preparation method of the complex phase enhancement superdispersed black body carbide metal ceramic coating as claimed in claim 8 as a boiler coating material.

10. The use of the multi-phase synergistic superdispersed black body carbide metal ceramic coating as a boiler coating material according to claim 9, characterized in that: The application method comprises the following steps: uniformly mixing the multi-phase enhanced super-dispersed black body carbide metal ceramic coating with a curing agent and spraying the mixture onto the inner surface of the boiler, and gradually sintering and curing the mixture as the furnace temperature rises, thereby obtaining a multi-phase enhanced super-dispersed black body carbide metal ceramic coating; The volume mass ratio of the multi-phase synergistic superdispersed black body carbonized metal ceramic coating to the curing agent is 680-760 mL: 30-50 g.

Images