Zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material and preparation method thereof

Abstract

The invention provides a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material and a preparation method thereof, belonging to the technical field of ceramics; the preparation method comprises the steps of graphene pretreatment, preparation of titanium dioxide / graphene microspheres, modification of titanium dioxide / graphene microspheres, functionalization of titanium dioxide / graphene microspheres, preparation of a ceramic mixture and molding and sintering; the titanium dioxide / graphene microsphere functionalization step comprises the steps of placing the modified titanium dioxide / graphene microspheres in xylene, adding bisphenol A type epoxy resin and triphenylphosphine, raising the temperature for stirring reaction, filtering out and washing, and then putting into N,N-dimethylformamide, stirring evenly, adding gallic acid and p-toluenesulfonic acid, raising the temperature for reaction, filtering, washing and drying after the reaction is completed, and preparing the functionalized titanium dioxide / graphene microspheres; the ceramic material prepared by the invention has high strength, good wear resistance and excellent high temperature resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramics, and in particular relates to a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material and a preparation method thereof. Background Art

[0002] With the rapid development of science and technology, it has become increasingly difficult to use a single material to meet people's production and work needs. People are increasingly using composite technology to prepare high-performance composite ceramic materials.

[0003] Zirconium boride, with the molecular formula ZrB2, has a stable crystal form and strong chemical bonds within the crystal, which makes zirconium boride have excellent comprehensive properties, such as high hardness, good wear resistance, strong conductivity, etc. It also has good compressive strength and flexural strength, which makes it have broad application prospects; and zirconium boride has a high melting point, good high temperature stability under high temperature conditions, and is insoluble in the metal matrix, which makes zirconium boride have a high application value in the ultra-high temperature field.

[0004] However, in the actual production process, the crystal structure of zirconium boride gives it a high melting point and a low volume diffusion rate. Zirconium boride also has extremely strong covalent bonds, which makes the densification sintering of zirconium boride ceramics more difficult. It requires higher pressure and temperature, resulting in an uneven structure of the zirconium boride ceramic material, which leads to a decrease in the toughness and other properties of the ceramic material, limiting the use of zirconium boride ceramics.

[0005] CN117209287A discloses a high-toughness ceramic material and a preparation method thereof, wherein zirconium diboride is used as a ceramic matrix, and silicon carbide nanowires, yttrium oxide, erbium oxide, modified pyrophyllite and fly ash are added, wherein the modified pyrophyllite is prepared by activating and modifying pyrophyllite with methacryloxypropyltrimethoxysilane, which effectively increases the toughness and bending strength of the finished ceramic product;

[0006] The zirconium boride-based ceramic material prepared by the above method has a fracture toughness of 10.96 MPa·m 1 / 2 The bending strength reaches 1281MPa, but the fracture toughness is still not high, and the high temperature resistance is poor. When the temperature reaches above 1600℃, the strength performance decreases rapidly, affecting the application of ceramic materials in high temperature fields.

[0007] CN103172382A discloses a method for preparing a zirconium diboride-silicon carbide ceramic-based composite material resistant to ultra-high temperature oxidation damage, specifically, ball milling zirconium boride powder and silicon carbide powder, hot pressing sintering after drying, and then performing oxidation inhibition treatment to obtain a product;

[0008] The ceramic material produced by this patent has a mass change rate of 17 mg / cm after oxidation at 1900°C for 15 minutes. 2 , it has good high temperature resistance, but its toughness and bending strength are poor, and its wear resistance is poor.

[0009] Graphene, a two-dimensional honeycomb crystal composed of carbon atoms, has high strength and hardness. During the sintering process, the lubricating effect of graphene can accelerate the rearrangement of particles, speed up mass transfer efficiency, and improve the density of the sintered body. It can also refine the grains, prevent the expansion of cracks, enhance the toughness of ceramic materials, improve sintering performance, and enhance the high temperature resistance and wear resistance of ceramic materials.

[0010] However, there is little research on zirconium boride / graphene composite ceramic materials in the prior art, and the applicant found during the research and development process that the bonding ability between graphene and the zirconium boride matrix is ​​weak and the load transfer capacity is poor, which will affect the comprehensive performance of the ceramic material;

[0011] Therefore, providing a zirconium boride / graphene composite ceramic material and a preparation method thereof, enhancing the fracture toughness and strength properties of the ceramic material, and improving the high temperature resistance and wear resistance are technical problems that need to be urgently solved in the prior art. Summary of the invention

[0012] In order to solve the technical problems existing in the prior art, the present invention provides a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material and a preparation method thereof. The ceramic material has high strength and high fracture toughness, good wear resistance and excellent high-temperature resistance.

[0013] In view of the above technical problems, the present invention adopts the following technical solutions:

[0014] A method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material, comprising the following contents:

[0015] 1. Graphene pretreatment

[0016] The graphene is placed in an ethanol solution, sodium octadecyl sulfate and fatty alcohol polyoxyethylene ether are added, the temperature is raised to 50-54° C., and ball milling is performed. The ball milling time is 28-32 minutes, the ball milling speed is 352-367 rpm, and the ball-to-material ratio is 3-5:1. After the ball milling is completed, the pretreated graphene is filtered, washed, and dried to obtain the pretreated graphene;

[0017] The particle size of the graphene is 240-260nm;

[0018] The mass ratio of the graphene, ethanol solution, sodium octadecyl sulfate and fatty alcohol polyoxyethylene ether is 11.7-12.3:105-114:0.6-1.0:0.5-0.7;

[0019] The mass concentration of the ethanol solution is 42-47%.

[0020] 2. Preparation of Titanium Dioxide / Graphene Microspheres

[0021] Deionized water was added to the pretreated graphene, and after stirring, titanium sulfate solution was added at a rate of 1.6-1.8 mL / min. After the addition was completed, ammonia water was added to control the pH to 7.0-7.2, and the mixture was stirred in a constant temperature water bath at 70-75° C. for 5.8-6.2 h. After the reaction was completed, the mixture was allowed to stand and cool, filtered and washed, and then dried at 78-82° C. for 6.8-7.3 h, and then calcined at 555-564° C. for 5.5-6.0 h. After naturally cooling to room temperature, titanium dioxide / graphene microspheres were obtained.

[0022] The mass volume ratio of the pretreated graphene, deionized water, and titanium sulfate solution is 10.4-10.6 g:95-106 g:35-40 mL;

[0023] The mass concentration of the titanium sulfate solution is 13-15%;

[0024] The mass concentration of the ammonia water is 17-22%.

[0025] 3. Titanium dioxide / graphene microsphere modification

[0026] (1) Primary modification

[0027] The titanium dioxide / graphene microspheres are placed in a 30-34wt% sodium hydroxide solution of 6-8 times the mass, the temperature is raised to 80-85°C, and the mixture is stirred for 3.3-3.7h. After the stirring is completed, the mixture is filtered out, washed and dried to obtain primary modified titanium dioxide / graphene microspheres;

[0028] (2) Modification again

[0029] Add carboxylated graphene to N,N-dimethylformamide, stir evenly, add primary modified titanium dioxide / graphene microspheres, dicyclohexylcarbodiimide and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, heat to 60-65°C at a rate of 0.8-1.2°C / min, perform ultrasonic treatment, the ultrasonic time is 28-32min, the ultrasonic frequency is 26-30kHz, the ultrasonic power is 282-295W, after the ultrasonic treatment, keep the temperature for reaction for 4.7-5.3h, while controlling the stirring speed to 344-355rpm, after the reaction is completed, filter, wash and dry to obtain modified titanium dioxide / graphene microspheres;

[0030] The volume mass ratio of the N,N-dimethylformamide, carboxylated graphene, primary modified titanium dioxide / graphene microspheres, dicyclohexylcarbodiimide and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane is 294-305 mL: 6.2-6.5 g: 13.5-14.0 g: 0.8-1.2 g: 1.3-1.5 g;

[0031] The preparation method of the carboxylated graphene is as follows: introducing deionized water into a reaction container, adding pretreated graphene, spermine and diethylenetriaminepropyltrimethoxysilane, raising the temperature to 68-72° C., stirring for reaction for 3.8-4.2 hours, filtering, washing and drying after the stirring reaction is completed to obtain amino graphene; placing the amino graphene in N,N-dimethylformamide, stirring evenly, adding succinic anhydride, controlling the temperature to 42-47° C., stirring for reaction for 3.3-3.7 hours, stirring at a speed of 865-875 rpm, filtering, washing and drying after the reaction is completed to obtain carboxylated graphene;

[0032] The mass ratio of the deionized water, pretreated graphene, spermine, and diethylenetriaminepropyltrimethoxysilane is 105-114:9.7-10.3:0.33-0.37:0.82-0.88;

[0033] The mass ratio of the amino graphene, N,N-dimethylformamide and succinic anhydride is 8.2-8.5 g:840-860 mL:8.8-9.3 g.

[0034] 4. Functionalization of titanium dioxide / graphene microspheres

[0035] The modified titanium dioxide / graphene microspheres are placed in xylene, bisphenol A epoxy resin and triphenylphosphine are added, the temperature is increased to 110-115°C, and the reaction is stirred for 5.8-6.2 hours. After the stirring reaction is completed, the mixture is filtered out and washed, and then put into N, N-dimethylformamide. After stirring evenly, gallic acid and 0.14-0.16g of p-toluenesulfonic acid are added, and ultrasonic treatment is performed. The ultrasonic time is 27-33min, the ultrasonic power is 134-145W, and the ultrasonic frequency is 17-22kHz. After the ultrasonic treatment is completed, the temperature is increased to 83-88°C, and the reaction is carried out for 6.3-6.7h. After the reaction is completed, the mixture is filtered, washed, and dried to obtain functionalized titanium dioxide / graphene microspheres.

[0036] The mass volume ratio of the modified titanium dioxide / graphene microspheres, xylene, bisphenol A epoxy resin, triphenylphosphine, N,N-dimethylformamide, gallic acid and p-toluenesulfonic acid is 9.5-10.0g:490-510mL:2.8-3.2g:0.20-0.23g:592-610mL:3.2-3.7g:0.14-0.16g.

[0037] 5. Preparation of Ceramic Mixture

[0038] Zirconium boride, silicon carbide and aluminum nitride are placed in anhydrous ethanol and stirred. After stirring evenly, hydroxyethyl cellulose, beeswax and octadecylmethyl dihydroxyethyl ammonium bromide are added and ball milling is performed. The ball milling time is 32-38 minutes, the ball milling speed is 414-425rpm, the ball-to-material ratio is 2-4:1, and the ball milling temperature is 43-47°C. After the ball milling is completed, 3.5-3.7g of functionalized titanium dioxide / graphene microspheres are added, and the mixture is stirred at 552-565rpm for 18-22 minutes. After the stirring is completed, the mixture is dried to obtain a ceramic mixture.

[0039] The mass ratio of the zirconium boride, silicon carbide, aluminum nitride, anhydrous ethanol, hydroxyethyl cellulose, beeswax and octadecylmethyl dihydroxyethyl ammonium bromide is 252-25.7:4.0-4.4:1.6-1.8:204-215:1.2-1.5:0.8-1.0:0.4-0.6;

[0040] The particle size of the zirconium boride is 280-320nm;

[0041] The particle size of the silicon carbide is 150-180nm;

[0042] The particle size of the aluminum nitride is 210-250 nm.

[0043] 6. Molding and sintering

[0044] The ceramic mixture is loaded into a graphite mold and hot-pressed and sintered in a nitrogen atmosphere. The heating rate is controlled at 18-22°C / min. When the temperature reaches 1810-1850°C, the pressure is increased to 30-34MPa and kept warm for 0.9-1.1h. After the insulation and pressure maintenance, the temperature is lowered at a rate of 10-15°C / min and the pressure is released along with the furnace to obtain zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material.

[0045] A zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material is prepared by the above preparation method.

[0046] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0047] 1. The present invention first pre-treats graphene to enhance the dispersion of graphene and avoid agglomeration, and then coats titanium dioxide on the surface of graphene. The two have good bonding ability, titanium dioxide is evenly coated on the surface of graphene, and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane is coated on the surface of titanium dioxide, which can effectively enhance the dispersion performance and improve the compatibility with other components. N-(β-aminoethyl)-γ-aminopropyltriethoxysilane can be used as a bridging agent to connect titanium dioxide / graphene microspheres and carboxylated graphene, thereby grafting graphene on the surface of titanium dioxide / graphene microspheres. The structure is stable and the connection is stable, which effectively exerts the enhancement performance of graphene, further increases the strength performance and wear resistance of ceramics, and ensures the stability of ceramic materials. In the functionalization step, epoxy resin and gallic acid are introduced, which react with the modified titanium dioxide / graphene microspheres respectively, and the epoxy resin can also enhance its bonding performance and Wear resistance, the functionalized titanium dioxide / graphene microspheres finally obtained present a complex and stable network structure, and when mixed with zirconium boride and other components to prepare a ceramic mixture, they have good compatibility with zirconium boride and other components, and good interface bonding ability, avoiding the problems of agglomeration, uneven dispersion, and weak bonding ability with the zirconium boride matrix when directly adding graphene, and can also fully and effectively exert the enhanced performance of graphene, improve the comprehensive performance of ceramic materials such as strength performance, wear resistance and high temperature resistance, extend the service life of ceramic materials, and expand the scope of use;

[0048] 2. The zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material prepared by the present invention has a flexural strength of 579.4-583.2 MPa and a fracture toughness of 13.0-13.4 MPa·m at 25°C. 1 / 2 , -20℃ fracture toughness is 12.3-12.7MPa·m 1 / 2 , hardness is 28.1-28.5Gpa, compressive strength is 669.5-674.2MPa;

[0049] 3. The zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material prepared by the present invention has good high-temperature oxidation resistance, and the mass change rate after being oxidized in air at 1600°C for 24 hours is 0.27-0.35%;

[0050] 4. The zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material prepared by the present invention has good high-temperature resistance. The ceramic material is heated to 1000°C at a rate of 30°C / min, kept at this temperature for 36 hours, and then heated to 1600°C at a rate of 20°C / min, kept at this temperature for 84 hours. After the standing is completed, it is naturally cooled to room temperature, and the bending strength is measured again to be 555.1-562.8MPa, and the fracture toughness is 12.6-13.1MPa·m 1 / 2 , the compressive strength is 635.4-645.2MPa. DETAILED DESCRIPTION

[0051] In order to more clearly understand the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described.

[0052] Example 1

[0053] 1. Graphene pretreatment

[0054] 12.0 g of graphene was placed in 110 g of 45 wt% ethanol solution, 0.8 g of sodium octadecyl sulfate and 0.6 g of fatty alcohol polyoxyethylene ether were added, the temperature was raised to 52° C., and ball milling was performed. The ball milling time was 30 min, the ball milling speed was 360 rpm, and the ball-to-material ratio was 4:1. After the ball milling was completed, the pretreated graphene was filtered, washed, and dried to obtain the pretreated graphene;

[0055] The particle size of the graphene is 250 nm.

[0056] 2. Preparation of Titanium Dioxide / Graphene Microspheres

[0057] To 10.5 g of pretreated graphene, 100 g of deionized water was added, and after stirring evenly, 37 mL of 14 wt% titanium sulfate solution was added, and the addition rate was controlled to be 1.7 mL / min. After the addition was completed, 20 wt% ammonia water was added to control the pH to 7.0, and the reaction was stirred in a constant temperature water bath at 72 ° C for 6.0 h. After the reaction was completed, it was allowed to stand and cool. After filtering and washing, it was dried at 80 ° C for 7.0 h, and then calcined at 560 ° C for 5.6 h. After naturally cooling to room temperature, titanium dioxide / graphene microspheres were obtained.

[0058] 3. Titanium dioxide / graphene microsphere modification

[0059] (1) Primary modification

[0060] The titanium dioxide / graphene microspheres were placed in a 32wt% sodium hydroxide solution of 7 times the mass, the temperature was raised to 82°C, and the mixture was stirred for 3.5 hours. After the stirring was completed, the mixture was filtered out, washed and dried to obtain primary modified titanium dioxide / graphene microspheres.

[0061] (2) Modification again

[0062] 6.3 g of carboxylated graphene was added to 300 mL of N, N-dimethylformamide, and after stirring, 13.7 g of primary modified titanium dioxide / graphene microspheres, 1.0 g of dicyclohexylcarbodiimide and 1.4 g of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane were added, and the temperature was raised to 62° C. at a rate of 1.0° C. / min, and ultrasonic treatment was performed. The ultrasonic time was 30 min, the ultrasonic frequency was 28 kHz, and the ultrasonic power was 290 W. After the ultrasonic treatment, the reaction was kept warm for 5.0 h, and the stirring speed was controlled to 350 rpm while the reaction was kept warm. After the reaction was completed, the modified titanium dioxide / graphene microspheres were obtained by filtering, washing and drying;

[0063] The preparation method of the carboxylated graphene is as follows: 110 g of deionized water is introduced into a reaction container, 10 g of pretreated graphene, 0.35 g of spermine and 0.85 g of diethylenetriaminepropyltrimethoxysilane are added, the temperature is increased to 70° C., and the stirring reaction is carried out for 4.0 hours. After the stirring reaction is completed, the amino graphene is filtered, washed and dried to obtain amino graphene; 8.4 g of amino graphene is placed in 850 mL of N, N-dimethylformamide, and after stirring evenly, 9.0 g of succinic anhydride is added, the temperature is controlled to 45° C., the stirring reaction is carried out for 3.5 hours, and the stirring speed is 870 rpm. After the reaction is completed, the amino graphene is filtered, washed and dried to obtain carboxylated graphene.

[0064] 4. Functionalization of titanium dioxide / graphene microspheres

[0065] 9.7 g of modified titanium dioxide / graphene microspheres were placed in 500 mL of xylene, 3.0 g of bisphenol A epoxy resin and 0.21 g of triphenylphosphine were added, the temperature was raised to 113°C, and the reaction was stirred for 6.0 h. After the stirring reaction was completed, it was filtered out and washed, and then put into 600 mL of N, N-dimethylformamide. After stirring evenly, 3.5 g of gallic acid and 0.15 g of p-toluenesulfonic acid were added, and ultrasonic treatment was performed. The ultrasonic time was 30 min, the ultrasonic power was 140 W, and the ultrasonic frequency was 20 kHz. After the ultrasonic treatment was completed, the temperature was raised to 85°C and the reaction was carried out. The reaction time was 6.5 h. After the reaction was completed, it was filtered, washed, and dried to obtain functionalized titanium dioxide / graphene microspheres.

[0066] 5. Preparation of Ceramic Mixture

[0067] 25.4 g of zirconium boride, 4.2 g of silicon carbide, and 1.7 g of aluminum nitride were placed in 210 g of anhydrous ethanol and stirred. After stirring evenly, 1.3 g of hydroxyethyl cellulose, 0.9 g of beeswax, and 0.5 g of octadecylmethyl dihydroxyethyl ammonium bromide were added and ball milled. The ball milling time was 35 min, the ball milling speed was 420 rpm, the ball-to-material ratio was 3:1, and the ball milling temperature was 45° C. After the ball milling, 3.6 g of functionalized titanium dioxide / graphene microspheres were added, and the mixture was stirred at 560 rpm for 20 min. After the stirring was completed, the mixture was dried to obtain a ceramic mixture.

[0068] The particle size of the zirconium boride is 300 nm;

[0069] The particle size of the silicon carbide is 170 nm;

[0070] The particle size of the aluminum nitride is 230 nm.

[0071] 6. Molding and sintering

[0072] The ceramic mixture is loaded into a graphite mold and hot-pressed sintered in a nitrogen atmosphere. The heating rate is controlled at 20°C / min. When the temperature reaches 1830°C, the pressure is increased to 32MPa and kept warm for 1.0h. After the insulation and pressure maintenance, the temperature is lowered at a rate of 12°C / min and the pressure is released along with the furnace to obtain zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material.

[0073] Example 2

[0074] 1. Graphene pretreatment

[0075] 11.7 g of graphene was placed in 105 g of 42 wt% ethanol solution, 0.6 g of sodium octadecyl sulfate and 0.5 g of fatty alcohol polyoxyethylene ether were added, the temperature was raised to 50° C., and ball milling was performed. The ball milling time was 28 min, the ball milling speed was 352 rpm, and the ball-to-material ratio was 3:1. After the ball milling was completed, the pretreated graphene was filtered, washed, and dried to obtain the pretreated graphene.

[0076] The particle size of the graphene is 240 nm.

[0077] 2. Preparation of Titanium Dioxide / Graphene Microspheres

[0078] To 10.4 g of pretreated graphene, 95 g of deionized water was added, and after stirring evenly, 35 mL of 13 wt % titanium sulfate solution was added, and the addition rate was controlled to be 1.6 mL / min. After the addition was completed, 17 wt % ammonia water was added to control the pH to 7.2, and the reaction was stirred in a constant temperature water bath at 70 ° C for 6.2 h. After the reaction was completed, it was allowed to stand and cool. After filtering and washing, it was dried at 78 ° C for 7.3 h, and then calcined at 555 ° C for 6.0 h. After naturally cooling to room temperature, titanium dioxide / graphene microspheres were obtained.

[0079] 3. Titanium dioxide / graphene microsphere modification

[0080] (1) Primary modification

[0081] The titanium dioxide / graphene microspheres were placed in a 30wt% sodium hydroxide solution of 6 times the mass, the temperature was raised to 80°C, and the mixture was stirred for 3.7 hours. After the stirring was completed, the mixture was filtered out, washed and dried to obtain primary modified titanium dioxide / graphene microspheres.

[0082] (2) Modification again

[0083] 6.2 g of carboxylated graphene was added to 294 mL of N, N-dimethylformamide, and after stirring, 13.5 g of primary modified titanium dioxide / graphene microspheres, 0.8 g of dicyclohexylcarbodiimide and 1.3 g of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane were added, and the temperature was raised to 60° C. at a rate of 0.8° C. / min, and ultrasonic treatment was performed. The ultrasonic time was 28 min, the ultrasonic frequency was 26 kHz, and the ultrasonic power was 282 W. After the ultrasonic treatment, the reaction was kept warm for 4.7 h, and the stirring speed was controlled to be 344 rpm while the reaction was kept warm. After the reaction was completed, the modified titanium dioxide / graphene microspheres were obtained by filtering, washing and drying;

[0084] The preparation method of the carboxylated graphene is as follows: 105g of deionized water is introduced into a reaction container, 9.7g of pretreated graphene, 0.33g of spermine and 0.82g of diethylenetriaminepropyltrimethoxysilane are added, the temperature is increased to 68°C, and the stirring reaction is carried out for 3.8h. After the stirring reaction is completed, the amino graphene is filtered, washed and dried to obtain amino graphene; 8.2g of amino graphene is placed in 840mL of N,N-dimethylformamide, after stirring evenly, 8.8g of succinic anhydride is added, the temperature is controlled to 42°C, the stirring reaction is carried out for 3.3h, and the stirring speed is 865rpm. After the reaction is completed, the amino graphene is filtered, washed and dried to obtain carboxylated graphene.

[0085] 4. Functionalization of titanium dioxide / graphene microspheres

[0086] 9.5 g of modified titanium dioxide / graphene microspheres were placed in 490 mL of xylene, 2.8 g of bisphenol A epoxy resin and 0.20 g of triphenylphosphine were added, the temperature was raised to 110 ° C, and the reaction was stirred for 5.8 h. After the stirring reaction was completed, it was filtered out and washed, and then put into 592 mL of N, N-dimethylformamide. After stirring evenly, 3.2 g of gallic acid and 0.14 g of p-toluenesulfonic acid were added, and ultrasonic treatment was performed. The ultrasonic time was 27 min, the ultrasonic power was 134 W, and the ultrasonic frequency was 17 kHz. After the ultrasonic treatment was completed, the temperature was raised to 83 ° C and the reaction was carried out for 6.3 h. After the reaction was completed, it was filtered, washed, and dried to obtain functionalized titanium dioxide / graphene microspheres.

[0087] 5. Preparation of Ceramic Mixture

[0088] 25.2 g of zirconium boride, 4.0 g of silicon carbide, and 1.6 g of aluminum nitride were placed in 204 g of anhydrous ethanol and stirred. After stirring evenly, 1.2 g of hydroxyethyl cellulose, 0.8 g of beeswax, and 0.4 g of octadecylmethyl dihydroxyethyl ammonium bromide were added and ball milled. The ball milling time was 32 min, the ball milling speed was 414 rpm, the ball-to-material ratio was 2:1, and the ball milling temperature was 43° C. After the ball milling, 3.5 g of functionalized titanium dioxide / graphene microspheres were added, and the mixture was stirred at 552 rpm for 18 min. After the stirring was completed, the mixture was dried to obtain a ceramic mixture.

[0089] The particle size of the zirconium boride is 280 nm;

[0090] The particle size of the silicon carbide is 150 nm;

[0091] The particle size of the aluminum nitride is 210 nm.

[0092] 6. Molding and sintering

[0093] The ceramic mixture is loaded into a graphite mold and hot-pressed sintered in a nitrogen atmosphere. The heating rate is controlled at 18°C / min. When the temperature reaches 1810°C, the pressure is increased to 34MPa and kept warm for 0.9h. After the insulation and pressure maintenance, the temperature is lowered at a rate of 10°C / min and the pressure is released along with the furnace to obtain zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material.

[0094] Example 3

[0095] 1. Graphene pretreatment

[0096] 12.3 g of graphene was placed in 114 g of 47 wt% ethanol solution, 1.0 g of sodium octadecyl sulfate and 0.7 g of fatty alcohol polyoxyethylene ether were added, the temperature was raised to 54° C., and ball milling was performed. The ball milling time was 32 min, the ball milling speed was 367 rpm, and the ball-to-material ratio was 5:1. After the ball milling was completed, the pretreated graphene was filtered, washed, and dried to obtain the pretreated graphene.

[0097] The particle size of the graphene is 260 nm.

[0098] 2. Preparation of Titanium Dioxide / Graphene Microspheres

[0099] To 10.6 g of pretreated graphene, add 106 g of deionized water, stir evenly, add 40 mL of 15 wt % titanium sulfate solution, and control the addition rate to 1.8 mL / min. After the addition is completed, add 22 wt % ammonia water to control the pH to 71. Stir the reaction in a constant temperature water bath at 75 ° C for 5.8 h. After the reaction is completed, let it stand and cool. After filtering and washing, dry it at 82 ° C for 6.8 h, and then calcine it at 564 ° C for 5.5 h. After naturally cooling to room temperature, titanium dioxide / graphene microspheres are obtained.

[0100] 3. Titanium dioxide / graphene microsphere modification

[0101] (1) Primary modification

[0102] The titanium dioxide / graphene microspheres were placed in 8 times the mass of a 34wt% sodium hydroxide solution, the temperature was raised to 85°C, and the mixture was stirred for 3.3 hours. After the stirring was completed, the mixture was filtered out, washed, and dried to obtain primary modified titanium dioxide / graphene microspheres.

[0103] (2) Modification again

[0104] 6.5 g of carboxylated graphene was added to 305 mL of N, N-dimethylformamide, and after stirring, 14.0 g of primary modified titanium dioxide / graphene microspheres, 1.2 g of dicyclohexylcarbodiimide and 1.5 g of N-(β-aminoethyl)-γ-aminopropyltriethoxysilane were added, and the temperature was raised to 65° C. at a rate of 1.2° C. / min, and ultrasonic treatment was performed. The ultrasonic time was 32 min, the ultrasonic frequency was 306 kHz, and the ultrasonic power was 295 W. After the ultrasonic treatment, the reaction was kept warm for 5.3 h, and the stirring speed was controlled to be 355 rpm while the reaction was kept warm. After the reaction was completed, the modified titanium dioxide / graphene microspheres were obtained by filtration, washing and drying.

[0105] The preparation method of the carboxylated graphene is as follows: 114g of deionized water is introduced into a reaction container, 10.3g of pretreated graphene, 0.37g of spermine and 0.88g of diethylenetriaminepropyltrimethoxysilane are added, the temperature is increased to 72°C, and the stirring reaction is carried out for 4.2h. After the stirring reaction is completed, the amino graphene is filtered, washed and dried to obtain amino graphene; 8.5g of amino graphene is placed in 860mL of N,N-dimethylformamide, and after stirring evenly, 9.3g of succinic anhydride is added, the temperature is controlled to 47°C, the stirring reaction is carried out for 3.7h, and the stirring speed is 875rpm. After the reaction is completed, the amino graphene is filtered, washed and dried to obtain carboxylated graphene.

[0106] 4. Functionalization of titanium dioxide / graphene microspheres

[0107] 10.0g of modified titanium dioxide / graphene microspheres were placed in 510mL of xylene, 3.2g of bisphenol A epoxy resin and 0.23g of triphenylphosphine were added, the temperature was raised to 115°C, and the reaction was stirred for 6.2h. After the stirring reaction was completed, the mixture was filtered out and washed, and then put into 610mL of N,N-dimethylformamide. After stirring evenly, 3.7g of gallic acid and 0.16g of p-toluenesulfonic acid were added, and ultrasonic treatment was performed. The ultrasonic time was 33min, the ultrasonic power was 145W, and the ultrasonic frequency was 22kHz. After the ultrasonic treatment was completed, the temperature was raised to 88°C and the reaction was carried out. The reaction time was 6.7h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain functionalized titanium dioxide / graphene microspheres.

[0108] 5. Preparation of Ceramic Mixture

[0109] 25.7 g of zirconium boride, 4.4 g of silicon carbide, and 1.8 g of aluminum nitride were placed in 215 g of anhydrous ethanol and stirred. After stirring evenly, 1.5 g of hydroxyethyl cellulose, 1.0 g of beeswax, and 0.6 g of octadecylmethyl dihydroxyethyl ammonium bromide were added and ball milled. The ball milling time was 38 min, the ball milling speed was 425 rpm, the ball-to-material ratio was 4:1, and the ball milling temperature was 47° C. After the ball milling, 3.7 g of functionalized titanium dioxide / graphene microspheres were added, and the mixture was stirred at 565 rpm for 22 min. After the stirring was completed, the mixture was dried to obtain a ceramic mixture.

[0110] The particle size of the zirconium boride is 320 nm;

[0111] The particle size of the silicon carbide is 180 nm;

[0112] The particle size of the aluminum nitride is 250 nm.

[0113] 6. Molding and sintering

[0114] The ceramic mixture is loaded into a graphite mold and hot-pressed sintered in a nitrogen atmosphere. The heating rate is controlled at 22°C / min. When the temperature reaches 1850°C, the pressure is increased to 30MPa and kept warm for 1.1h. After the insulation and pressure maintenance, the temperature is lowered at a rate of 15°C / min and the pressure is released along with the furnace to obtain zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material.

[0115] Comparative Example 1

[0116] Based on Example 1, the changes are as follows:

[0117] (1) The step of preparing titanium dioxide / graphene microspheres is to add 100 g of deionized water to 10.5 g of pretreated graphene, stir evenly, add 37 mL of titanium dioxide solution, stir evenly, dry at 80° C. for 7.0 h, and then calcine at 560° C. for 5.6 h, and naturally cool to room temperature to obtain titanium dioxide / graphene microspheres;

[0118] The titanium dioxide solution is prepared by mixing titanium dioxide and deionized water, wherein the mass ratio of titanium dioxide to deionized water is 14:86;

[0119] (2) in the second modification step of the titanium dioxide / graphene microspheres, the carboxylated graphene component is omitted and the carboxylated graphene is replaced by an equal amount of the primary modified titanium dioxide / graphene microspheres;

[0120] The rest of the operations are the same.

[0121] Comparative Example 2

[0122] Based on Example 1, the changes are as follows:

[0123] (1) The graphene pretreatment step is omitted. In the step of preparing titanium dioxide / graphene microspheres and the method of preparing carboxylated graphene, the pretreated graphene is replaced by graphene without any treatment in equal amounts, and the particle size of the graphene is 250 nm.

[0124] (2) The functionalization step of titanium dioxide / graphene microspheres is omitted, and in the step of preparing the ceramic mixture, the functionalized titanium dioxide / graphene microspheres are replaced with modified titanium dioxide / graphene microspheres in equal amounts;

[0125] The rest of the operations are the same.

[0126] Performance Testing

[0127] The ceramic materials obtained in Examples 1-3 and Comparative Examples 1-2 were subjected to the following performance tests, and the test results are as follows:

[0128]

[0129] Among them, the mass change rate in high temperature resistance performance refers to the mass change after the ceramic material is oxidized in air at 1600℃ for 24h;

[0130] The flexural strength, fracture toughness and compressive strength of high temperature resistance are measured by heating the ceramic material to 1000℃ at a rate of 30℃ / min, keeping it at that temperature for 36 hours, then heating it to 1600℃ at a rate of 20℃ / min, keeping it at that temperature for 84 hours. After the temperature is naturally lowered to room temperature, the flexural strength, fracture toughness and compressive strength are tested again.

[0131] The present invention first pre-treats graphene to enhance the dispersion of graphene and avoid agglomeration, and then coats titanium dioxide on the surface of graphene. The two have good bonding ability, titanium dioxide is evenly coated on the surface of graphene, and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane is coated on the surface of titanium dioxide, which can effectively enhance the dispersion performance and improve the compatibility with other components. N-(β-aminoethyl)-γ-aminopropyltriethoxysilane can be used as a bridging agent to connect titanium dioxide / graphene microspheres and carboxylated graphene, thereby grafting graphene on the surface of titanium dioxide / graphene microspheres. The structure is stable and the connection is stable, which effectively exerts the enhancement performance of graphene, further increases the strength performance and wear resistance of ceramics, and ensures the stability of ceramic materials. In the functionalization step, epoxy resin and gallic acid are introduced, which react with the modified titanium dioxide / graphene microspheres respectively, and the epoxy resin can also enhance its bonding performance and Wear resistance, the functionalized titanium dioxide / graphene microspheres finally obtained present a complex and stable network structure. When they are mixed with zirconium boride and other ingredients to prepare ceramic mixtures, they have good compatibility with zirconium boride and other ingredients, and good interface bonding ability, avoiding the problems of agglomeration, uneven dispersion, and weak bonding ability with the zirconium boride matrix when graphene is directly added. It can also fully and effectively exert the enhanced performance of graphene, improve the comprehensive performance of ceramic materials such as strength, wear resistance and high temperature resistance, extend the service life of ceramic materials, and expand the scope of use.

[0132] Comparative Example 1 is to directly mix titanium dioxide powder and graphene, the bonding force between the two is poor, and the compatibility is not good. In the modification process, aminosilane coupling is used for modification, and the modification of titanium dioxide powder and graphene is insufficient. The modified microspheres are still partially inhomogeneous. In addition, carboxylated graphene is added in Comparative Example 1, which cannot be grafted with the microspheres. The microspheres modified by the aminosilane coupling agent are directly functionalized, and the crosslinking of epoxy resin and gallic acid with the modified titanium dioxide / graphene microspheres is not stable. The ceramic mixture prepared with zirconium boride and other ingredients has poor homogeneity, which reduces the strength and stability of the product, and has poor oxidation resistance and high temperature resistance.

[0133] Comparative Example 2 omits the graphene pretreatment step, the titanium dioxide coating of the graphene is uneven, and only the titanium dioxide / graphene is modified without functionalization. The titanium dioxide / graphene microspheres obtained have poor stability, poor adhesion, and weak bonding with other components, which affects the overall performance of the product.

[0134] Unless otherwise specified, all percentages used in the present invention are by mass.

[0135] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material, characterized in that: The method comprises the steps of graphene pretreatment, preparation of titanium dioxide / graphene microspheres, modification of titanium dioxide / graphene microspheres, functionalization of titanium dioxide / graphene microspheres, preparation of ceramic mixtures and molding and sintering; The step of preparing titanium dioxide / graphene microspheres is as follows: adding deionized water to the pretreated graphene, stirring evenly, adding titanium sulfate solution, controlling the addition rate to be 1.6-1.8 mL / min, adding ammonia water to control the pH to be 7.0-7.2, stirring and reacting in a constant temperature water bath at 70-75° C. for 5.8-6.2 hours, standing and cooling after the reaction, filtering and washing, drying, calcining, and naturally cooling to room temperature to obtain titanium dioxide / graphene microspheres; The modification of titanium dioxide / graphene microspheres includes primary modification and secondary modification; The second modification step is to add carboxylated graphene to N,N-dimethylformamide, stir evenly, add primary modified titanium dioxide / graphene microspheres, dicyclohexylcarbodiimide and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, heat to 60-65°C at a rate of 0.8-1.2°C / min, perform ultrasonic treatment, and after the end of the ultrasonic treatment, heat and react for 4.7-5.3h, while controlling the stirring speed to 344-355rpm, after the reaction is completed, filter, wash and dry to obtain modified titanium dioxide / graphene microspheres; The preparation method of the carboxylated graphene is as follows: introducing deionized water into a reaction container, adding pretreated graphene, spermine and diethylenetriaminepropyltrimethoxysilane, raising the temperature to 68-72° C., stirring for reaction for 3.8-4.2 hours, filtering, washing and drying after the stirring reaction is completed to obtain amino graphene; placing the amino graphene in N,N-dimethylformamide, stirring evenly, adding succinic anhydride, controlling the temperature to 42-47° C., stirring for reaction for 3.3-3.7 hours, stirring at a speed of 865-875 rpm, filtering, washing and drying after the reaction is completed to obtain carboxylated graphene; The titanium dioxide / graphene microsphere functionalization step is to place the modified titanium dioxide / graphene microsphere in xylene, add bisphenol A epoxy resin and triphenylphosphine, increase the temperature to 110-115° C., stir and react for 5.8-6.2 hours, filter out and wash after the stirring reaction, then put into N, N-dimethylformamide, stir evenly, add gallic acid and p-toluenesulfonic acid, perform ultrasonic treatment, increase the temperature to 83-88° C. after the ultrasonic treatment, react for 6.3-6.7 hours, filter, wash and dry after the reaction, and obtain the functionalized titanium dioxide / graphene microsphere.

2. The method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material according to claim 1, characterized in that: The graphene pretreatment step comprises placing the graphene in an ethanol solution, adding sodium octadecyl sulfate and fatty alcohol polyoxyethylene ether, raising the temperature to 50-54° C., and performing ball milling treatment. The ball milling time is 28-32 minutes, the ball milling speed is 352-367 rpm, and the ball-to-material ratio is 3-5:

1. After the ball milling is completed, filtering, washing, and drying are performed to obtain the pretreated graphene. The particle size of the graphene is 240-260nm; The mass ratio of the graphene, ethanol solution, sodium octadecyl sulfate and fatty alcohol polyoxyethylene ether is 11.7-12.3:105-114:0.6-1.0:0.5-0.7; The mass concentration of the ethanol solution is 42-47%.

3. The method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material according to claim 1, characterized in that: In the step of preparing titanium dioxide / graphene microspheres, the mass volume ratio of the pretreated graphene, deionized water, and titanium sulfate solution is 10.4-10.6 g:95-106 g:35-40 mL; The mass concentration of the titanium sulfate solution is 13-15%; The mass concentration of the ammonia water is 17-22%; The drying temperature is 78-82°C and the drying time is 6.8-7.3h; The calcination temperature is 555-564° C. and the calcination time is 5.5-6.0 h.

4. The method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material according to claim 1, characterized in that: The primary modification step is to put the titanium dioxide / graphene microspheres into 6-8 times the mass of 30-34wt% sodium hydroxide solution, increase the temperature to 80-85°C, keep stirring for 3.3-3.7h, filter out after stirring, wash and dry to obtain primary modified titanium dioxide / graphene microspheres.

5. The method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material according to claim 1, characterized in that: In the second modification step, the volume mass ratio of the N,N-dimethylformamide, carboxylated graphene, primary modified titanium dioxide / graphene microspheres, dicyclohexylcarbodiimide and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane is 294-305 mL: 6.2-6.5 g: 13.5-14.0 g: 0.8-1.2 g: 1.3-1.5 g; The ultrasonic treatment has an ultrasonic time of 28-32 min, an ultrasonic frequency of 26-30 kHz, and an ultrasonic power of 282-295 W.

6. The method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material according to claim 1, characterized in that: In the preparation method of the carboxylated graphene, the mass ratio of the deionized water, the pretreated graphene, spermine, and diethylenetriaminepropyltrimethoxysilane is 105-114:9.7-10.3:0.33-0.37:0.82-0.88; The mass ratio of the amino graphene, N,N-dimethylformamide and succinic anhydride is 8.2-8.5 g:840-860 mL:8.8-9.3 g.

7. The method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material according to claim 1, characterized in that: In the titanium dioxide / graphene microsphere functionalization step, the mass volume ratio of the modified titanium dioxide / graphene microsphere, xylene, bisphenol A epoxy resin, triphenylphosphine, N,N-dimethylformamide, gallic acid and p-toluenesulfonic acid is 9.5-10.0 g:490-510 mL:2.8-3.2 g:0.20-0.23 g:592-610 mL:3.2-3.7 g:0.14-0.16 g; The ultrasonic treatment has an ultrasonic time of 27-33 min, an ultrasonic power of 134-145 W, and an ultrasonic frequency of 17-22 kHz.

8. The method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material according to claim 1, characterized in that: The step of preparing the ceramic mixture is to place zirconium boride, silicon carbide and aluminum nitride in anhydrous ethanol and stir them, add hydroxyethyl cellulose, beeswax and octadecylmethyl dihydroxyethyl ammonium bromide after stirring evenly, and perform ball milling, wherein the ball milling time is 32-38 minutes, the ball milling speed is 414-425 rpm, the ball-to-material ratio is 2-4:1, the ball milling temperature is 43-47° C., after the ball milling is completed, 3.5-3.7 g of functionalized titanium dioxide / graphene microspheres are added, and the mixture is stirred at 552-565 rpm for 18-22 minutes. After the stirring is completed, the mixture is dried to obtain the ceramic mixture; The mass ratio of the zirconium boride, silicon carbide, aluminum nitride, anhydrous ethanol, hydroxyethyl cellulose, beeswax and octadecylmethyl dihydroxyethyl ammonium bromide is 252-25.7:4.0-4.4:1.6-1.8:204-215:1.2-1.5:0.8-1.0:0.4-0.6; The particle size of the zirconium boride is 280-320nm; The particle size of the silicon carbide is 150-180nm; The particle size of the aluminum nitride is 210-250 nm.

9. The method for preparing a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material according to claim 1, characterized in that: The molding and sintering steps are as follows: loading the ceramic mixture into a graphite mold, hot pressing and sintering in a nitrogen atmosphere, controlling the heating rate to be 18-22°C / min, and when the temperature reaches 1810-1850°C, increasing the pressure to 30-34MPa, and maintaining the temperature for 0.9-1.1h. After the temperature is maintained, cooling at a rate of 10-15°C / min and releasing the pressure along with the furnace to obtain a zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material.

10. The zirconium boride / graphene composite wear-resistant and high-temperature resistant ceramic material prepared according to the preparation method according to any one of claims 1 to 9.

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