Coating material and preparation method thereof

Abstract

The invention discloses a coating material and a preparation method thereof, and belongs to the technical field of coating materials. The coating material is composed of tungsten carbide powder, cobalt powder, tantalum carbide, chromium carbide, titanium silicon carbide, yttrium oxide, absolute ethyl alcohol, polyethylene glycol and a graphite dispersing agent. The preparation method comprises the steps of ball-milling mixing, spray-drying granulation, high-temperature consolidation and the like. The graphite dispersing agent is prepared through the steps of graphite oxidation, acylating chlorination, free radical polymerization and the like, and has excellent dispersing performance. Compared with the prior art, the coating material prepared by the method has low porosity, high hardness and good stability, and is suitable for the fields of machine manufacturing, aerospace, automobile manufacturing and the like.

Description

Technical Field

[0001] This invention relates to the field of coating materials technology, and in particular to a coating material and its preparation method. Background Technology

[0002] In modern industry, coating materials are widely used in machinery manufacturing, aerospace, automotive manufacturing, and electronic equipment to improve the wear resistance, corrosion resistance, oxidation resistance, and service life of materials. Traditional coating materials are mainly composed of metal powders and ceramic powders, but these materials suffer from problems such as high porosity, insufficient hardness, and particle agglomeration during high-temperature sintering, which limits their use in high-performance applications.

[0003] In recent years, with the development of nanotechnology, nanocomposite materials have gradually become a research hotspot. Nanocomposite materials significantly improve the mechanical and physical properties of traditional materials by introducing nanoscale reinforcing phases. However, nanoparticles are prone to agglomeration during sintering, leading to increased porosity and reduced coating density and hardness. Therefore, developing a coating material and its preparation method that can effectively disperse nanoparticles, reduce porosity, and improve coating hardness and stability has significant scientific and practical application value.

[0004] While some existing coating material preparation technologies can improve coating performance to some extent, shortcomings remain. For example, Chinese patent application CN108893696A discloses a nano-carbide-reinforced tungsten carbide-based composite powder with high erosion and crack resistance, and its preparation method. This method improves the erosion resistance and toughness of the coating by adding a nano-carbide reinforcing phase, but there is still room for improvement in porosity and hardness. Another Chinese patent application CN115011927A discloses a vacuum-deposited coating material. Through optimization of specific components, it improves the adhesion and color saturation of the coating, but its high-temperature stability and mechanical properties still need further improvement. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to develop a coating material and its preparation method with low porosity, high hardness, and good stability by optimizing the composition and preparation process of the coating material, in order to meet the needs of high-performance applications.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a coating material, comprising the following components by weight: 60-100 parts tungsten carbide powder, 10-20 parts cobalt powder, 4-6 parts tantalum carbide, 3-5 parts chromium carbide, 1-3 parts titanium silicon carbide, 0.4-0.6 parts yttrium oxide, 30-50 parts anhydrous ethanol, 4-8 parts polyethylene glycol, and 1-3 parts graphite dispersant.

[0008] The preparation method of the graphite dispersant includes the following steps:

[0009] S1. Mix graphite with concentrated sulfuric acid, add potassium permanganate under ice bath conditions, control the temperature and then heat the mixture, centrifuge and wash until pH is neutral and freeze dry to obtain pretreated graphite.

[0010] S2. The pretreated graphite is reacted with thionyl chloride and treated with unsaturated alcohol to obtain modified graphite.

[0011] S3. The modified graphite is dispersed in water containing sodium dodecylbenzenesulfonate and polyvinylpyrrolidone, and treated with aqueous solutions of reactive hydrophilic monomers and catalysts. After filtration and washing, a graphite dispersant is obtained.

[0012] The preparation method of the coating material is as follows:

[0013] Step 1: Place tungsten carbide powder, cobalt powder, tantalum carbide, chromium carbide, titanium silicon carbide, and yttrium oxide in a ball mill jar, add anhydrous ethanol, polyethylene glycol, and graphite dispersant, and mix using a ball milling process to obtain a slurry;

[0014] Step 2: Spray dry and granulate the slurry prepared in Step 1 using water atomization to obtain precursor composite particles. In a hydrogen protective atmosphere, the precursor composite particles are solidified at high temperature and kept at the temperature until they are completely densified. After cooling, they are mechanically crushed and graded and screened to obtain the coating material.

[0015] The mixing time for the ball milling process is 10-30 hours.

[0016] The furnace temperature for high-temperature consolidation is 1050-1150℃.

[0017] Preferably, the graphite dispersant is prepared by the following method, in parts by weight:

[0018] S1. Mix 1-3 parts of graphite with 80-120 parts of 95-98wt% concentrated sulfuric acid, add 3-8 parts of potassium permanganate under ice bath conditions, control the addition temperature to ≤10-20℃, then treat at 20-35℃ for 1-5 hours, raise the temperature to 80-95℃ and continue treatment for 20-60 minutes, centrifuge, wash with water until pH neutral, freeze dry to obtain pretreated graphite;

[0019] S2. React 1-3 parts of the pretreated graphite prepared in step S1 with 15-25 parts of thionyl chloride at 60-70℃ for 24-72 hours, add 0.5-2 parts of unsaturated alcohol, and treat at 60-80℃ for 1-8 hours to obtain modified graphite.

[0020] S3. Disperse the modified graphite prepared in step S2 in 150-250 parts of water containing 0.005-0.02 parts of sodium dodecylbenzenesulfonate and 0.003-0.008 parts of polyvinylpyrrolidone, add 30-40 parts of 5-15 wt% aqueous solution of reactive hydrophilic monomer and 10-20 parts of 0.3-0.8 wt% aqueous solution of catalyst, treat at 60-75℃ for 2-6 hours, filter and wash to obtain graphite dispersant.

[0021] The unsaturated alcohol is at least one of allyl alcohol, linalool, and nerol.

[0022] The reactive hydrophilic monomer is at least one of polyethylene glycol acrylate and polyethylene glycol diacrylate.

[0023] The catalyst is ammonium persulfate.

[0024] The roles of each substance in the preparation method of the graphite dispersant in this invention are as follows:

[0025] Graphite, as a carbon-based framework, is oxidized and exfoliated to form graphene oxide sheets, providing π-π stacking anchor points.

[0026] Concentrated sulfuric acid, acting as a strong acid medium, is inserted between the graphite layers to activate the carbon layers and promote deep oxidation.

[0027] Potassium permanganate, as the core oxidant, hydroxylates the edges / base surfaces of graphite into carboxyl groups, thereby enhancing hydrophilicity.

[0028] Thionyl chloride reacts with the carboxyl groups of graphite to generate highly reactive acyl chloride groups.

[0029] The hydroxyl groups of allyl alcohol are grafted with acyl chloride terminal double bonds, providing reaction sites for polymerization in step S3.

[0030] Sodium dodecylbenzenesulfonate, as an anionic surfactant, reduces the surface tension of modified graphite and prevents agglomeration.

[0031] Polyvinylpyrrolidone (PVP) acts as a steric stabilizer, providing steric hindrance through long-chain coated particles.

[0032] Polyethylene glycol acrylate contains acrylate double bonds and polyether chains. After grafting, it forms a structure with hydrophobic anchoring and hydrophilic extension, providing electrostatic repulsion.

[0033] Ammonium persulfate acts as a free radical initiator, decomposing to generate sulfate free radicals, which drive the graft polymerization reaction.

[0034] The design concept of this invention, a graphite dispersant, lies in endowing graphite with excellent dispersing properties through chemical modification. First, graphite is oxidized using concentrated sulfuric acid and potassium permanganate to form graphene oxide flakes rich in oxygen-containing functional groups (such as carboxyl and hydroxyl groups). These functional groups not only enhance the hydrophilicity of graphite but also provide reaction sites for subsequent chemical modification. Next, the carboxyl groups are converted to acyl chloride groups using thionyl chloride and then esterified with unsaturated alcohols (such as allyl alcohol) to introduce double bonds, providing active sites for subsequent polymerization reactions. Finally, in the aqueous phase, reactive hydrophilic monomers (such as polyethylene glycol acrylate) are grafted onto the edges of the graphene oxide flakes via free radical polymerization, forming a dispersant with an amphiphilic structure of "anchoring and extension." This structure allows the hydrophobic portion of the dispersant to be strongly adsorbed onto the substrate surface through π-π stacking, hydrogen bonding, and hydrophobic interactions, while the hydrophilic portion extends into the aqueous phase, providing steric hindrance and electrostatic repulsion, effectively inhibiting particle aggregation and thus significantly improving the performance of the coating material.

[0035] Compared with existing technologies, it has the following advantages:

[0036] 1) This invention, by optimizing the preparation process of graphite dispersant, can effectively reduce the formation of pores in the coating, thereby significantly improving the density and mechanical properties of the coating. This low-porosity coating exhibits superior performance in terms of corrosion resistance and wear resistance.

[0037] 2) This invention, through the rational design of the dispersant's chemical structure and preparation process, enables the coating to form a more uniform microstructure during sintering, thereby significantly improving the coating's hardness and wear resistance. This high-performance coating has significant advantages in high-load, high-wear applications.

[0038] 3) The coating material of this invention exhibits good chemical and thermal stability during high-temperature sintering, avoiding performance degradation caused by high-temperature decomposition or phase transformation. This stability allows the coating to maintain good performance during long-term use, thereby extending the service life of the coating. Detailed Implementation

[0039] Main source of materials:

[0040] Tungsten carbide powder, item number: KR-WC-2, average particle size: 1µm, Anhui Nanhao Electronic Technology Co., Ltd.

[0041] Cobalt powder, grade: Co12-1, particle size: 0.6-4um, Hebei Yinbai Alloy Welding Materials Co., Ltd.

[0042] Tantalum carbide, grade: TaC, particle size: 500 (mesh), Qinghe County Zhongzhou Alloy Materials Co., Ltd.

[0043] Chromium carbide, particle size: 500-800 mesh, grade: CrC-01, Nangong Yingtai Metal Materials Co., Ltd.

[0044] Titanium silicon carbide, particle size: 1-10um, item number: 854984, Qinghe County Nuotu Welding Materials Co., Ltd.

[0045] Yttrium oxide, item number: CY-Y203-02, average particle size: 1µm, Nangong Yingtai Metal Materials Co., Ltd.

[0046] Polyethylene glycol, model: PEG400, Guangzhou Suixin Chemical Co., Ltd.

[0047] Graphite, density: 1.5–1.7 g / cm³ 3 Mohs hardness: 2.1, flake size: 0.08mm, crystal grain size: 0.08mm, Qingdao Risheng Graphite Co., Ltd.

[0048] Polyethylene glycol acrylate, item number: PB92286, Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0049] Polyethylene glycol diacrylate, item number: PB98330, Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0050] Polyvinylpyrrolidone, model: PVPK30, Guangdong Yuemei Chemical Co., Ltd.

[0051] Allyl polyoxyethylene ether, model: APEG-400, hydroxyl value: 127~155mgKOH / g, Haian Petrochemical Plant, Jiangsu Province.

[0052] All other raw materials used in the embodiments and comparative examples of this invention are commercially available products.

[0053] Example 1

[0054] A method for preparing a coating material is as follows, in parts by weight:

[0055] Step 1: Place 80 parts of tungsten carbide powder, 15 parts of cobalt powder, 5 parts of tantalum carbide, 4 parts of chromium carbide, 2 parts of titanium silicon carbide, and 0.5 parts of yttrium oxide into a ball mill jar, add 40 parts of anhydrous ethanol, 6 parts of polyethylene glycol, and 2 parts of graphite dispersant, and mix by ball milling for 20 hours to obtain a slurry;

[0056] Step 2: Spray dry and granulate the slurry prepared in Step 1 using water atomization to obtain precursor composite particles. In a hydrogen protective atmosphere, the precursor composite particles are solidified at high temperature. The furnace temperature for high-temperature solidification is set at 1100℃ and held at that temperature until fully densified. After cooling, the particles are mechanically crushed and graded and screened to obtain the coating material.

[0057] The preparation method of the graphite dispersant is as follows, in parts by weight:

[0058] S1. Mix 2 parts of graphite with 100 parts of 95wt% concentrated sulfuric acid, add 5 parts of potassium permanganate under ice bath conditions, control the addition temperature to ≤20℃, then treat at 30℃ for 3 hours, raise the temperature to 90℃ and continue treatment for 40 minutes, centrifuge, wash with water until pH neutral, freeze dry to obtain pretreated graphite.

[0059] S2. React 2 parts of the pretreated graphite prepared in step S1 with 20 parts of thionyl chloride at 65°C for 48 hours, add 1 part of allyl alcohol, and treat at 70°C for 5 hours to obtain modified graphite.

[0060] S3. Disperse the modified graphite prepared in step S2 in 200 parts of water containing 0.01 parts of sodium dodecylbenzenesulfonate and 0.005 parts of polyvinylpyrrolidone, add 35 parts of 10 wt% polyethylene glycol acrylate aqueous solution and 15 parts of 0.5 wt% ammonium persulfate aqueous solution, treat at 70°C for 4 hours, filter and wash to obtain graphite dispersant.

[0061] Example 2

[0062] The preparation method of the coating material is basically the same as that in Example 1, except that the preparation method of the graphite dispersant is different.

[0063] The preparation method of the graphite dispersant is as follows, in parts by weight:

[0064] S1. Mix 2 parts of graphite with 100 parts of 95wt% concentrated sulfuric acid, add 5 parts of potassium permanganate under ice bath conditions, control the addition temperature to ≤20℃, then treat at 30℃ for 3 hours, raise the temperature to 90℃ and continue treatment for 40 minutes, centrifuge, wash with water until pH neutral, freeze dry to obtain pretreated graphite.

[0065] S2. Two parts of the pretreated graphite prepared in step S1 were reacted with 20 parts of thionyl chloride at 65°C for 48 hours, and one part of linalool was added. The mixture was then treated at 70°C for 5 hours to obtain modified graphite.

[0066] S3. Disperse the modified graphite prepared in step S2 in 200 parts of water containing 0.01 parts of sodium dodecylbenzenesulfonate and 0.005 parts of polyvinylpyrrolidone, add 35 parts of 10 wt% polyethylene glycol acrylate aqueous solution and 15 parts of 0.5 wt% ammonium persulfate aqueous solution, treat at 70°C for 4 hours, filter and wash to obtain graphite dispersant.

[0067] Example 3

[0068] The preparation method of the coating material is basically the same as that in Example 1, except that the preparation method of the graphite dispersant is different.

[0069] The preparation method of the graphite dispersant is as follows, in parts by weight:

[0070] S1. Mix 2 parts of graphite with 100 parts of 95wt% concentrated sulfuric acid, add 5 parts of potassium permanganate under ice bath conditions, control the addition temperature to ≤20℃, then treat at 30℃ for 3 hours, raise the temperature to 90℃ and continue treatment for 40 minutes, centrifuge, wash with water until pH neutral, freeze dry to obtain pretreated graphite.

[0071] S2. Two parts of the pretreated graphite prepared in step S1 were reacted with 20 parts of thionyl chloride at 65°C for 48 hours, and one part of nerol was added. The mixture was then treated at 70°C for 5 hours to obtain modified graphite.

[0072] S3. Disperse the modified graphite prepared in step S2 in 200 parts of water containing 0.01 parts of sodium dodecylbenzenesulfonate and 0.005 parts of polyvinylpyrrolidone, add 35 parts of 10 wt% polyethylene glycol acrylate aqueous solution and 15 parts of 0.5 wt% ammonium persulfate aqueous solution, treat at 70°C for 4 hours, filter and wash to obtain graphite dispersant.

[0073] Example 4

[0074] The preparation method of the coating material is basically the same as that in Example 1, except that the preparation method of the graphite dispersant is different.

[0075] The preparation method of the graphite dispersant is as follows, in parts by weight:

[0076] S1. Mix 2 parts of graphite with 100 parts of 95wt% concentrated sulfuric acid, add 5 parts of potassium permanganate under ice bath conditions, control the addition temperature to ≤20℃, then treat at 30℃ for 3 hours, raise the temperature to 90℃ and continue treatment for 40 minutes, centrifuge, wash with water until pH neutral, freeze dry to obtain pretreated graphite.

[0077] S2. React 2 parts of the pretreated graphite prepared in step S1 with 20 parts of thionyl chloride at 65°C for 48 hours, add 1 part of allyl alcohol, and treat at 70°C for 5 hours to obtain modified graphite.

[0078] S3. Disperse the modified graphite prepared in step S2 in 200 parts of water containing 0.01 parts of sodium dodecylbenzenesulfonate and 0.005 parts of polyvinylpyrrolidone, add 35 parts of 10 wt% polyethylene glycol diacrylate aqueous solution and 15 parts of 0.5 wt% ammonium persulfate aqueous solution, treat at 70°C for 4 hours, filter and wash to obtain graphite dispersant.

[0079] Comparative Example 1

[0080] The preparation method of the coating material is basically the same as that in Example 1, except that the preparation method of the graphite dispersant is different.

[0081] The preparation method of the graphite dispersant is as follows, in parts by weight:

[0082] S1. Mix 2 parts of graphite with 100 parts of 95wt% concentrated sulfuric acid, add 5 parts of potassium permanganate under ice bath conditions, control the addition temperature to ≤20℃, then treat at 30℃ for 3 hours, raise the temperature to 90℃ and continue treatment for 40 minutes, centrifuge, wash with water until pH neutral, freeze dry to obtain pretreated graphite.

[0083] S2. Two parts of the pretreated graphite prepared in step S1 were reacted with 20 parts of thionyl chloride at 65°C for 48 hours, and one part of hydroxypropyl acrylate was added. The mixture was then treated at 70°C for 5 hours to obtain modified graphite.

[0084] S3. Disperse the modified graphite prepared in step S2 in 200 parts of water containing 0.01 parts of sodium dodecylbenzenesulfonate and 0.005 parts of polyvinylpyrrolidone, add 35 parts of 10 wt% polyethylene glycol acrylate aqueous solution and 15 parts of 0.5 wt% ammonium persulfate aqueous solution, treat at 70°C for 4 hours, filter and wash to obtain graphite dispersant.

[0085] Comparative Example 2

[0086] The preparation method of the coating material is basically the same as that in Example 1, except that the preparation method of the graphite dispersant is different.

[0087] The preparation method of the graphite dispersant is as follows, in parts by weight:

[0088] S1. Mix 2 parts of graphite with 100 parts of 95wt% concentrated sulfuric acid, add 5 parts of potassium permanganate under ice bath conditions, control the addition temperature to ≤20℃, then treat at 30℃ for 3 hours, raise the temperature to 90℃ and continue treatment for 40 minutes, centrifuge, wash with water until pH neutral, freeze dry to obtain pretreated graphite.

[0089] S2. Two parts of the pretreated graphite prepared in step S1 were reacted with 20 parts of thionyl chloride at 65°C for 48 hours, and one part of allyl alcohol was added. The mixture was then treated at 70°C for 5 hours to obtain modified graphite.

[0090] S3. Disperse the modified graphite prepared in step S2 in 200 parts of water containing 0.01 parts of sodium dodecylbenzenesulfonate and 0.005 parts of polyvinylpyrrolidone, add 35 parts of 10 wt% allyl polyoxyethylene ether aqueous solution and 15 parts of 0.5 wt% ammonium persulfate aqueous solution, treat at 70°C for 4 hours, filter and wash to obtain graphite dispersant.

[0091] Comparative Example 3

[0092] The preparation method of a coating material is basically the same as that in Example 1, except that the graphite dispersant is replaced with an equal amount of graphite.

[0093] Comparative Example 4

[0094] The preparation method of a coating material is basically the same as that in Example 1, except that the graphite dispersant is not added.

[0095] Test Example 1

[0096] Porosity test

[0097] The substrate used for spraying was 45# carbon steel. First, the carbon steel surface was cleaned, derusted, and dried. Then, it was sandblasted to increase surface roughness, with the resulting surface roughness ranging from 6.0 to 12.5 μm. Using the coating materials prepared in the embodiments and comparative examples of this invention as the spraying raw material, kerosene supersonic flame spraying technology was employed. The spraying process parameters were as follows: kerosene flow rate of 22 L / h, kerosene pressure of 1.2 MPa, oxygen flow rate of 850 L / min, oxygen pressure of 1.8 MPa, powder feed rate of 90 g / min, nitrogen flow rate of 12 L / min, nitrogen pressure of 1.0 MPa, and spraying distance of 350 mm. Using the above process parameters, a composite coating was successfully prepared.

[0098] To measure the porosity of the composite coating, mercury porosimetry was used. An AutoPore V9600 mercury porosimeter was used according to ASTM D4404-18, with a pressure range of 0.1–60,000 psi. The test results are shown in Table 1.

[0099] Table 1

[0100] Experimental protocol Porosity / % Example 1 0.24 Example 2 0.42 Example 3 0.38 Example 4 0.31 Comparative Example 1 0.65 Comparative Example 2 0.53 Comparative Example 3 1.25 Comparative Example 4 1.83

[0101] Test Example 2

[0102] Hardness test

[0103] The hardness of the composite coating prepared in Test Example 1 was measured using a microhardness tester equipped with a diamond microVickers indenter.

[0104] The test results are shown in Table 2.

[0105] Table 2

[0106] Experimental protocol Microhardness of coating (GPa) Example 1 38.5 Example 2 34.2 Example 3 35.1 Example 4 36.8 Comparative Example 1 30.5 Comparative Example 2 31.7 Comparative Example 3 28.3 Comparative Example 4 26.4

[0107] Example 1 utilizes allyl alcohol for efficient esterification with acyl chloride groups in the S2 stage of a graphite dispersant. Allyl alcohol has a small molecular weight and no complex side chains, resulting in almost no residual decomposition during sintering at 1100℃, significantly reducing porosity formation. Simultaneously, the high reactivity of the primary hydroxyl groups in allyl alcohol ensures a high double bond grafting rate, allowing the dispersant to form a dense adsorption layer in the coating, effectively inhibiting particle agglomeration. In contrast, linalool and nerol exhibit significant residual carbonization of their terpene skeletons at high temperatures, leading to increased porosity; hydroxypropyl acrylate decomposes its ester groups to produce gas, resulting in high porosity. Therefore, allyl alcohol achieves optimized minimum porosity and high hardness through a dual mechanism of reducing carbon residue and enhancing interfacial bonding.

[0108] The flexible molecular chains formed by the monoacrylate groups of polyethylene glycol acrylate optimize the dispersion of slurry particles and improve sintering fluidity, thereby increasing hardness. The moderate polyether chain length balances hydrophilicity and heat resistance, preventing the formation of a soft phase at high temperatures and thus maintaining high hardness. The double-crosslinked structure of polyethylene glycol diacrylate, however, is too rigid and hinders particle flow; allyl polyoxyethylene ether is prone to forming a soft phase at high temperatures.

Claims

1. A method for preparing a coating material, characterized in that, It comprises the following components by weight: 60-100 parts tungsten carbide powder, 10-20 parts cobalt powder, 4-6 parts tantalum carbide, 3-5 parts chromium carbide, 1-3 parts titanium silicon carbide, 0.4-0.6 parts yttrium oxide, 30-50 parts anhydrous ethanol, 4-8 parts polyethylene glycol, and 1-3 parts graphite dispersant; The preparation method of the graphite dispersant includes the following steps: S1. Mix graphite with concentrated sulfuric acid, add potassium permanganate under ice bath conditions, control the temperature and then heat the mixture, centrifuge and wash until pH is neutral and freeze dry to obtain pretreated graphite. S2. The pretreated graphite is reacted with thionyl chloride and treated with unsaturated alcohol to obtain modified graphite. S3. The modified graphite is dispersed in water containing sodium dodecylbenzenesulfonate and polyvinylpyrrolidone, and treated with aqueous solutions of reactive hydrophilic monomers and catalysts. After filtration and washing, a graphite dispersant is obtained.

2. The method for preparing the coating material as described in claim 1, characterized in that, The method is as follows: Step 1: Place tungsten carbide powder, cobalt powder, tantalum carbide, chromium carbide, titanium silicon carbide, and yttrium oxide in a ball mill jar, add anhydrous ethanol, polyethylene glycol, and graphite dispersant, and mix using a ball milling process to obtain a slurry; Step 2: Spray dry and granulate the slurry prepared in Step 1 using water atomization to obtain precursor composite particles. In a hydrogen protective atmosphere, the precursor composite particles are solidified at high temperature and kept at the temperature until they are completely densified. After cooling, they are mechanically crushed and graded and screened to obtain the coating material.

3. The method for preparing the coating material as described in claim 2, characterized in that, The mixing time for the ball milling process is 10-30 hours.

4. The method for preparing the coating material as described in claim 2, characterized in that, The furnace temperature for high-temperature consolidation is 1050-1150℃.

5. The method for preparing the coating material as described in claim 1 or 2, characterized in that, The preparation method of the graphite dispersant is as follows, in parts by weight: S1. Mix 1-3 parts of graphite with 80-120 parts of 95-98wt% concentrated sulfuric acid, add 3-8 parts of potassium permanganate under ice bath conditions, control the addition temperature to ≤10-20℃, then treat at 20-35℃ for 1-5 hours, raise the temperature to 80-95℃ and continue treatment for 20-60 minutes, centrifuge, wash with water until pH neutral, freeze dry to obtain pretreated graphite; S2. React 1-3 parts of the pretreated graphite prepared in step S1 with 15-25 parts of thionyl chloride at 60-70℃ for 24-72 hours, add 0.5-2 parts of unsaturated alcohol, and treat at 60-80℃ for 1-8 hours to obtain modified graphite. S3. Disperse the modified graphite prepared in step S2 in 150-250 parts of water containing 0.005-0.02 parts of sodium dodecylbenzenesulfonate and 0.003-0.008 parts of polyvinylpyrrolidone, add 30-40 parts of 5-15 wt% aqueous solution of reactive hydrophilic monomer and 10-20 parts of 0.3-0.8 wt% aqueous solution of catalyst, treat at 60-75℃ for 2-6 hours, filter and wash to obtain graphite dispersant.

6. The method for preparing the coating material as described in claim 5, characterized in that, The unsaturated alcohol is at least one of allyl alcohol, linalool, and nerol.

7. The method for preparing the coating material as described in claim 5, characterized in that, The reactive hydrophilic monomer is at least one of polyethylene glycol acrylate and polyethylene glycol diacrylate.

8. The method for preparing the coating material as described in claim 5, characterized in that, The catalyst is ammonium persulfate.

9. A coating material, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.