Lanthanum-doped aluminum oxide composite grinding powder and preparation method thereof

Abstract

The invention discloses lanthanum-doped aluminum oxide composite grinding powder and a preparation method thereof, and relates to the technical field of aluminum oxide grinding powder, the aluminum oxide grinding powder has high grinding efficiency, is suitable for grinding and polishing materials such as metal, glass and ceramic, and has wide applicability; lanthanum serving as a rare earth element is doped into the aluminum oxide grinding powder, so that growth of aluminum oxide grains can be better inhibited, and the high temperature resistance of the grinding powder is improved; the lanthanum-doped aluminum oxide grinding powder has higher wear resistance, the oxygen vacancy concentration on the surface of aluminum oxide can be adjusted by doping lanthanum, and the polishing performance of the grinding powder is optimized.

Description

Technical Field

[0001] The invention relates to the technical field of abrasive powders, in particular to a lanthanum-doped alumina composite abrasive powder and a preparation method thereof. Background Art

[0002] Alumina grinding powder, as one of the most widely used abrasives in industry, has significant advantages, but also has certain limitations.

[0003] Compared to other abrasive materials, alumina abrasive powder has high hardness and excellent wear resistance. It is resistant to decomposition at high temperatures and is resistant to acids and alkalis. Its raw material reserves are abundant and its production process is mature. However, existing alumina abrasive powder is brittle and easily broken, leading to premature passivation of the abrasive particles, affecting processing efficiency. It is also prone to adhesion when machining soft materials, reducing grinding efficiency.

[0004] In summary, in order to solve the problems existing in the prior art and improve the grinding efficiency of abrasive powder, the present invention provides a lanthanum-doped alumina composite abrasive powder and a preparation method thereof. Summary of the Invention

[0005] The object of the present invention is to provide a lanthanum-doped alumina composite grinding powder and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A lanthanum-doped alumina composite grinding powder and a preparation method thereof, comprising the following steps:

[0008] Step 1: mixing high-alumina fly ash and sodium carbonate in a mass ratio of 1:1, calcining at a calcination temperature of 800-810°C for 1-2 hours, coarsely grinding, placing in 2.5 mol / L dilute hydrochloric acid, acid leaching at room temperature for 60-70 minutes, and filtering; adjusting the pH value of the filtrate to 5 to generate a precipitate; filtering and washing the generated precipitate, and then dissolving the precipitate with sodium hydroxide solution until the pH of the liquid phase is 10, filtering and washing again to obtain a sodium aluminate solution; introducing carbon dioxide into the solution to generate an aluminum hydroxide precipitate, drying, and grinding to obtain aluminum hydroxide;

[0009] Step 2: Hydrothermally treat aluminum hydroxide, dry it, and then calcine it to obtain γ-Al2O3; modify γ-Al2O3 with 0.3g of silane coupling agent KH550 to obtain modified γ-Al2O3; add molybdenum disulfide and graphene to Tris-HCl and dopamine hydrochloride, and ultrasonically disperse them; add γ-Al2O3 to the above solution, stir it magnetically and ultrasonically disperse it, then let the mixed solution stand for 24 to 28 hours, pour off the supernatant, wash it with anhydrous ethanol by centrifugation, dry the obtained product for 24 to 28 hours, grind it, and obtain a composite powder. Mix manganese dioxide, titanium dioxide, calcium oxide, and lanthanum oxide evenly as a sintering aid;

[0010] Step 3: Grind the composite powder and the sintering aid for 10 to 12 hours to obtain a raw material; calcine the raw material at a high temperature to obtain a calcined powder; add ethanol to the calcined powder, grind the mixture for 48 to 50 hours, and dry to obtain lanthanum-doped alumina composite grinding powder.

[0011] A more optimized method is as follows: in step 2, molybdenum disulfide is added to a Tris-HCl (pH = 8.5) buffer solution, ultrasonically treated for 2 to 4 hours, 0.2 g of dopamine hydrochloride is added to the solution, stirred for 12 to 14 hours, washed with deionized water 5 to 7 times, ethanol is added, and ultrasonically dispersed; γ-Al2O3 is added to the above solution, magnetically stirred and ultrasonically dispersed, and then the mixed solution is allowed to stand for 24 to 28 hours, the supernatant is poured out, and the mixture is centrifuged and washed with anhydrous ethanol for 6 to 8 times. The obtained product is dried in a vacuum drying oven at 60 to 70°C for 24 to 26 hours to obtain a molybdenum disulfide alumina complex.

[0012] More optimized, in step 3, 0.2 g of nanographene is added to anhydrous ethanol, and then the micronized molybdenum disulfide alumina composite is added to the above solution, ultrasonically dispersed for 6 to 8 hours, and then vacuum dried and ground to obtain a composite powder;

[0013] More optimally, in the raw materials, the amount of the sintering-aid powder added accounts for 2 to 2.8 wt % of the composite powder.

[0014] More preferably, the sintering aid comprises the following substances: calculated by weight: 2 to 3 parts of manganese dioxide, 1.5 to 2.5 parts of titanium dioxide, 1 to 2 parts of calcium oxide, and 0.5 to 1.5 parts of lanthanum oxide;

[0015] More optimally, in step 3, the high-temperature calcination method is: heating to 200-300°C at a rate of 2-4°C / min, and heat treating for 20-40 minutes; then heating to 1200-1400°C at a rate of 4-8°C / min, calcining for 1-2 hours, and naturally cooling to 800-810°C and calcining for 3-5 hours to obtain calcined powder.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. Adding large-particle molybdenum disulfide (MoS2) to abrasive powder improves processing efficiency, but results in higher surface roughness. Adding small-particle nanographene to abrasive powder allows for fine grinding and significantly reduces surface roughness, but results in lower processing efficiency. Therefore, adding both MoS2 and Nanographene to abrasive powder and mixing them evenly to form a mixed powder allows for both fine grinding and improved grinding efficiency.

[0018] 2. Adding dopamine to the grinding powder can effectively prevent the agglomeration of alumina particles, reduce the viscosity of the slurry, disperse the grinding powder particles evenly, achieve better grinding effect, and improve the wear resistance of the grinding powder.

[0019] 3. The doping of lanthanum inhibits the agglomeration of alumina particles, forming a more uniform particle size distribution of 0.8 to 1.2 μm, thereby improving the surface treatment quality; the prepared lanthanum-doped alumina composite abrasive powder has higher hardness and good wear resistance.

[0020] 4. Both molybdenum disulfide and graphene have a lamellar structure. The layers are bonded by weak van der Waals forces and are easy to slide off, which gives them good lubrication properties. Adding molybdenum disulfide and graphene to alumina can increase the wear resistance of the composite material.

[0021] 5. Add glacial acetic acid to adjust the solution pH to 3 to allow the silane coupling agent to fully hydrolyze; the reaction process is that the silane coupling agent first undergoes hydrolysis to form silanol groups, then undergoes dehydration condensation reaction, and then undergoes hydrogen bonding with the hydroxyl groups on the surface of γ-Al2O3, and finally dehydrates to obtain modified γ-Al2O3.

[0022] 6. Alumina has a high surface energy and a large specific surface area, making it very easy to agglomerate and form secondary particles. This prevents uniform dispersion in organic systems, leading to a decrease in the performance of composite materials. Silane coupling agent KH550 is a good inorganic particle surface modifier that can organically modify inorganic nanoparticles and improve the dispersibility of inorganic particles in organic solvents.

[0023] 7. The sintering aid of MnO2-TiO2-CaO-La2O3 system is used to maintain the liquid phase amount in the sintering system, which has a pinning effect on grain boundary movement and effectively inhibits the growth of grains. At the same time, a small amount of La2O3 rare earth oxide is introduced to reduce the sintering temperature of Al2O3 to about 30°C, and its surface microstructure is also improved. This is mainly because La2O3 is a network denaturing ion that can decompose the melt network and promote sintering.

[0024] 8. In the scheme, aluminum hydroxide is extracted mainly from high-aluminum fly ash. High-aluminum fly ash contains a relatively high amount of aluminum oxide, which can be used to prepare aluminum oxide products. DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0026] There is no specific limitation on the sources and models of the substances involved in the present invention, and illustratively include: high-alumina fly ash is provided by a thermal power plant in North China; molybdenum disulfide, with a particle size of 1 μm, is provided by Suzhou Yuante New Materials Co., Ltd.; manganese dioxide has a particle size of 2 μm, CAS number 1313-13-9, and is provided by Wuhan Tuocai Technology Co., Ltd.; titanium dioxide has a particle size of 0.5 μm, CAS number 13463-67-7, and is provided by Dalian Aiwolei Building Materials Co., Ltd.; calcium oxide has a particle size of 3 μm, CAS number 1305-78-8, and is provided by Leping Chunhua Environmental Protection Materials Co., Ltd.; lanthanum oxide has a particle size of 1 μm, CAS number 1312-81-8, and is provided by Zibo Ruibokang Rare Earth Materials Co., Ltd.; and graphene has a particle size of 30 nm and is provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.

[0027] Example 1: A lanthanum-doped alumina composite grinding powder and its preparation method:

[0028] Step 1: Mix high-alumina fly ash and sodium carbonate in a mass ratio of 1:1, calcine at a calcination temperature of 800°C for 1 hour, coarsely grind, place in 2.5 mol / L dilute hydrochloric acid, acid-leach at room temperature for 60 minutes, and filter; adjust the pH value of the filtrate to 5 to generate a precipitate; filter and wash the generated precipitate, then dissolve the precipitate with sodium hydroxide solution until the pH of the liquid phase is 10, filter and wash again to obtain a sodium aluminate solution; introduce carbon dioxide into the solution to generate aluminum hydroxide precipitate, dry, and ball-mill to obtain aluminum hydroxide powder;

[0029] Step 2: (1) placing aluminum hydroxide powder in an autoclave, heating it, and hydrothermally treating it at 160°C for 3 hours, washing it with deionized water, and drying it in an oven at 70°C; calcining the dried hydrothermal product in a high-temperature furnace for 3 hours to obtain γ-Al2O3;

[0030] (2) 0.3 g of silane coupling agent KH550 was added to 100 mL of deionized water and dispersed uniformly, and then glacial acetic acid was added to adjust the pH to 3 to prepare a KH550 hydrolyzate; 100 mL of a solution with a mass ratio of 1:1 of ethanol and water was prepared, γ-Al2O3 was added, and ultrasonic dispersion was performed for 30 minutes to prepare a γ-Al2O3 dispersion; KH550 hydrolyzate was added to the γ-Al2O3 dispersion, and the mixture was heated under reflux at 80°C with a magnetic stirrer for 1 hour. After the reaction was completed, the mixture was centrifuged and washed with anhydrous ethanol 3 times to remove the unloaded silane coupling agent on the surface of γ-Al2O3, and dried in an oven at 80°C for 24 hours, ground and dehydrated to obtain a modified γ-Al2O3;

[0031] (3) 0.04 g of micronized molybdenum disulfide was added to 100 mL of Tris-HCl (pH = 8.5) buffer solution, ultrasonicated for 2 h, then 0.2 g of dopamine hydrochloride was added to the solution, stirred for 12 h, washed with deionized water 5 times, added with 100 mL of ethanol, and ultrasonically dispersed; 0.5 g of modified γ-Al2O3 was added to the above solution, magnetically stirred and ultrasonically dispersed, allowed to stand for 24 h, the supernatant was discarded, and the product was washed 6 times by centrifugation with anhydrous ethanol. The obtained product was dried in a vacuum drying oven at 60 ° C for 24 h to obtain a micronized molybdenum disulfide alumina composite;

[0032] (4) Weighing manganese dioxide, titanium dioxide, calcium oxide, and lanthanum oxide, and mixing them evenly to form a sintering aid;

[0033] The sintering aid includes: by weight: 2 parts of manganese dioxide, 1.5 parts of titanium dioxide, 1 part of calcium oxide, and 0.5 parts of lanthanum oxide;

[0034] Step 3: (1) 0.2 g of nanographene was added to 100 mL of anhydrous ethanol, and 0.5 g of micronized molybdenum disulfide alumina composite was added to the above solution, and ultrasonically dispersed for 6 h, vacuum dried, and ground to obtain a composite powder. The obtained composite powder was mixed and ground with a sintering aid (the amount of the sintering aid added accounted for 2 wt% of the composite powder), and ball milled for 8 h to obtain a raw material;

[0035] (2) heating the raw material to 200°C at a rate of 2°C / min and heat treating for 20 minutes; then heating to 1200°C at a rate of 4°C / min and calcining for 1 hour, then naturally cooling to 800°C and calcining for 3 hours to obtain calcined powder;

[0036] (3) Take 0.5 g of the calcined powder, add 100 mL of ethanol, mix and grind, ball mill for 48 h, and dry to obtain lanthanum-doped alumina composite grinding powder.

[0037] Example 2: A lanthanum-doped alumina composite grinding powder and its preparation method:

[0038] Step 1: Mix high-alumina fly ash and sodium carbonate in a mass ratio of 1:1, calcine at a calcination temperature of 810°C for 2 hours, coarsely grind, place in 2.5 mol / L dilute hydrochloric acid, acid-leach at room temperature for 70 minutes, and filter; adjust the pH value of the filtrate to 5 to generate a precipitate; filter and wash the generated precipitate, then dissolve the precipitate with sodium hydroxide solution until the pH of the liquid phase is 10, filter and wash again to obtain a sodium aluminate solution; introduce carbon dioxide into the solution to generate an aluminum hydroxide precipitate, dry and ball-mill for 12 hours to obtain aluminum hydroxide powder;

[0039] Step 2: (1) placing aluminum hydroxide powder in an autoclave, programmed temperature increase, hydrothermally treating at 180°C for 4 hours, washing with deionized water, and drying in an oven at 80°C; calcining the dried hydrothermal product in a high-temperature furnace for 4 hours to obtain γ-Al2O3;

[0040] (2) 0.3 g of silane coupling agent KH550 was added to 100 mL of deionized water and dispersed uniformly, and then glacial acetic acid was added to adjust the pH to 3 to prepare a KH550 hydrolyzate; 100 mL of a solution with a mass ratio of 1:1 of ethanol and water was prepared, γ-Al2O3 was added, and ultrasonic dispersion was performed for 30 minutes to prepare a γ-Al2O3 dispersion; the KH550 hydrolyzate was added to the γ-Al2O3 dispersion, and the mixture was heated under reflux at a constant temperature of 80°C with a magnetic stirrer for 1 hour. After the reaction was completed, the mixture was centrifuged and washed with anhydrous ethanol 3 times to remove the unloaded silane coupling agent on the surface of γ-Al2O3, and dried in an oven at 80°C for 28 hours, ground and dehydrated to obtain a modified γ-Al2O3;

[0041] (3) 0.04 g of micronized molybdenum disulfide was added to 100 mL of Tris-HCl (pH = 8.5) buffer solution, ultrasonicated for 4 h, then 0.2 g of dopamine hydrochloride was added to the solution, stirred for 14 h, washed with deionized water 5 times, added with 100 mL of ethanol, and ultrasonically dispersed; 0.5 g of modified γ-Al2O3 was added to the above solution, magnetically stirred and ultrasonically dispersed, allowed to stand for 28 h, the supernatant was discarded, and the product was washed with anhydrous ethanol by centrifugation 6 times. The obtained product was dried in a vacuum drying oven at 60 ° C for 26 h to obtain a micronized molybdenum disulfide alumina composite;

[0042] (4) Weighing manganese dioxide, titanium dioxide, calcium oxide, and lanthanum oxide, and mixing them evenly to form a sintering aid;

[0043] The sintering aid includes: by weight: 3 parts of manganese dioxide, 2.5 parts of titanium dioxide, 2 parts of calcium oxide, and 1.5 parts of lanthanum oxide;

[0044] Step 3: (1) 0.2 g of nanographene was added to 100 mL of anhydrous ethanol, and 0.5 g of a micronized molybdenum disulfide alumina composite was added to the above solution, and ultrasonically dispersed for 8 h. The composite powder was vacuum dried and ground to obtain a composite powder. The obtained composite powder was mixed with a sintering aid (the amount of the sintering aid added was 2.8 wt% of the composite powder) and ground for 12 h to obtain a raw material;

[0045] (2) heating the raw material to 300°C at a rate of 4°C / min and heat treating for 40 minutes; then heating the raw material to 1400°C at a rate of 8°C / min and calcining for 1 hour, then naturally cooling the raw material to 810°C and calcining for 5 hours to obtain a calcined powder;

[0046] (3) 0.5 g of the calcined powder was added to 100 mL of ethanol, the mixture was ball-milled for 50 h, and dried to obtain lanthanum-doped alumina composite grinding powder.

[0047] Example 3: Preparation method of lanthanum-doped alumina composite grinding powder:

[0048] Step 1: Mix high-alumina fly ash and sodium carbonate in a mass ratio of 1:1, calcine at a calcination temperature of 805°C for 1.5 hours, coarsely grind, place in 2.5 mol / L dilute hydrochloric acid, acid-leach at room temperature for 65 minutes, and filter; adjust the pH value of the filtrate to 5 to form a precipitate; filter and wash the generated precipitate, then dissolve the precipitate with sodium hydroxide solution until the pH of the liquid phase reaches 10, filter and wash again to obtain a sodium aluminate solution; introduce carbon dioxide into the solution to generate an aluminum hydroxide precipitate, dry, and ball-mill for 11 hours to obtain an aluminum hydroxide powder;

[0049] Step 2: (1) placing aluminum hydroxide powder in an autoclave, programmed to heat, hydrothermally treating at 165°C for 3.5 hours, washing with deionized water, and drying in an oven at 75°C; calcining the dried hydrothermal product in a high-temperature furnace for 3.5 hours to obtain γ-Al2O3;

[0050] (2) 0.3 g of silane coupling agent KH550 was added to 100 mL of deionized water and dispersed uniformly, and then glacial acetic acid was added to adjust the pH to 3 to prepare a KH550 hydrolyzate; 100 mL of a solution with a mass ratio of 1:1 of ethanol and water was prepared, γ-Al2O3 was added, and ultrasonic dispersion was performed for 30 minutes to prepare a γ-Al2O3 dispersion; the KH550 hydrolyzate was added to the γ-Al2O3 dispersion, and the mixture was heated under reflux at a constant temperature of 80°C with a magnetic stirrer for 1 hour. After the reaction was completed, the mixture was centrifuged and washed with anhydrous ethanol 3 times to remove the unloaded silane coupling agent on the surface of γ-Al2O3, and dried in an oven at 80°C for 26 hours, ground and dehydrated to obtain a modified γ-Al2O3;

[0051] (3) 0.04 g of micronized molybdenum disulfide was added to 100 mL of Tris-HCl (pH = 8.5) buffer solution, ultrasonicated for 3 h, then 0.2 g of dopamine hydrochloride was added to the solution, stirred for 13 h, washed with deionized water 5 times, added with 100 mL of ethanol, and ultrasonically dispersed; 0.5 g of modified γ-Al2O3 was added to the above solution, magnetically stirred and ultrasonically dispersed, allowed to stand for 26 h, the supernatant was discarded, and the product was washed with anhydrous ethanol by centrifugation 6 times. The obtained product was dried in a vacuum drying oven at 60 ° C for 25 h to obtain a micronized molybdenum disulfide alumina composite;

[0052] (4) Weighing manganese dioxide, titanium dioxide, calcium oxide, and lanthanum oxide, and mixing them evenly to form a sintering aid;

[0053] The sintering aid includes: by weight: 2.5 parts of manganese dioxide, 2 parts of titanium dioxide, 1.5 parts of calcium oxide, and 1 part of lanthanum oxide;

[0054] Step 3: (1) adding 0.2 g of nanographene to 100 mL of anhydrous ethanol, and then adding 0.5 g of micron molybdenum disulfide alumina composite to the above solution, ultrasonically dispersing for 7 h, vacuum drying and grinding to obtain composite powder, and mixing the obtained composite powder with a sintering aid (the amount of the sintering aid added accounts for 2.4 wt% of the composite powder) and grinding for 10 h to obtain a raw material;

[0055] (2) heating the raw material to 250°C at a rate of 3°C / min and heat treating for 30 minutes; then heating it to 1300°C at a rate of 6°C / min and calcining it for 1.5 hours, then naturally cooling it to 805°C and calcining it for 4 hours to obtain a calcined powder;

[0056] (3) 0.5 g of the calcined powder was added to 100 mL of ethanol and the mixture was ball-milled for 49 h and dried to obtain lanthanum-doped alumina composite grinding powder.

[0057] Comparative Example 1: No sintering aid was introduced, and the rest was referred to Example 1; the specific changes were:

[0058] Step 3: (1) adding 0.2 g of nanographene to 100 mL of anhydrous ethanol, and then adding 0.5 g of micron molybdenum disulfide alumina composite to the above solution, ultrasonically dispersing for 6 h, vacuum drying and grinding to obtain composite powder, and grinding the obtained composite powder for 8 h to obtain a raw material;

[0059] (2) heating the raw material to 200°C at a rate of 2°C / min and heat treating for 20 minutes; then heating to 1200°C at a rate of 4°C / min and calcining for 1 hour, then naturally cooling to 800°C and calcining for 3 hours to obtain calcined powder;

[0060] (3) 0.5 g of the calcined powder was added with ethanol (the amount of ethanol added was 1 wt% of the calcined powder), mixed and ball-milled for 48 h, and dried to obtain lanthanum-doped alumina composite grinding powder.

[0061] Comparative Example 2: No nanographene was added, and the rest was referred to Example 1; the specific changes were as follows:

[0062] Step 3: (1) mixing and grinding the micronized molybdenum disulfide alumina composite and a sintering aid (the amount of the sintering aid added accounts for 2 wt% of the micronized molybdenum disulfide alumina composite powder) for 10 h to obtain a raw material;

[0063] (2) heating the raw material to 200°C at a rate of 2°C / min and heat treating for 20 minutes; then heating to 1200°C at a rate of 4°C / min and calcining for 1 hour, then naturally cooling to 800°C and calcining for 3 hours to obtain calcined powder;

[0064] (3) 0.5 g of the calcined powder was added to ethanol, mixed and ground for 48 h, and dried to obtain alumina composite grinding powder.

[0065] Comparative Example 3: Dopamine hydrochloride was not added, and the rest was referred to Example 1, with specific changes as follows:

[0066] Step 2: (1) placing aluminum hydroxide powder in an autoclave, programmed to heat, hydrothermally treating at 160°C for 3 h, washing with deionized water, and drying in an oven at 70°C; calcining the dried hydrothermal product in a high-temperature furnace for 3 h to obtain γ-Al2O3;

[0067] (2) 0.3 g of silane coupling agent KH550 was added to deionized water and dispersed uniformly, and then glacial acetic acid was added to adjust the pH to 3 to prepare a KH550 hydrolyzate; a solution with a mass ratio of ethanol to water of 1:1 was prepared, γ-Al2O3 was added, and ultrasonic dispersion was performed for 30 minutes to prepare a γ-Al2O3 dispersion; the KH550 hydrolyzate was added to the γ-Al2O3 dispersion, and the mixture was heated under reflux at 80°C with a magnetic stirrer for 1 hour. After the reaction was completed, the mixture was centrifuged and washed with anhydrous ethanol for 3 times to remove the unloaded silane coupling agent on the surface of γ-Al2O3, and dried in an oven at 80°C for 24 hours, ground and dehydrated to obtain a modified γ-Al2O3;

[0068] (3) adding 0.04 g of micron molybdenum disulfide to ethanol and ultrasonically dispersing the mixture; adding 0.5 g of γ-Al2O3 to the above solution, magnetically stirring and ultrasonically dispersing the mixture, allowing the mixture to stand for 24 h, discarding the supernatant, and washing the mixture six times with anhydrous ethanol by centrifugation. The resulting product was dried in a vacuum drying oven at 60° C. for 24 h to obtain a micron molybdenum disulfide-alumina composite;

[0069] (4) Weighing manganese dioxide, titanium dioxide, calcium oxide, and lanthanum oxide, and mixing them evenly to form a sintering aid;

[0070] The sintering aid includes: by weight: 2 parts of manganese dioxide, 1.5 parts of titanium dioxide, 1 part of calcium oxide, and 0.5 parts of lanthanum oxide.

[0071] Comparative Example 4: No micronized molybdenum disulfide was added. The rest was referred to Example 1, with specific changes as follows:

[0072] Step 2: (1) placing aluminum hydroxide powder in an autoclave, programmed to heat, hydrothermally treating at 160°C for 3 h, washing with deionized water, and drying in an oven at 70°C; calcining the dried hydrothermal product in a high-temperature furnace for 3 h to obtain γ-Al2O3;

[0073] (2) 0.3 g of silane coupling agent KH550 was added to 100 mL of deionized water and dispersed uniformly, and then glacial acetic acid was added to adjust the pH to 3 to prepare a KH550 hydrolyzate; 100 mL of a solution with a mass ratio of 1:1 of ethanol and water was prepared, γ-Al2O3 was added, and ultrasonic dispersion was performed for 30 minutes to prepare a γ-Al2O3 dispersion; KH550 hydrolyzate was added to the γ-Al2O3 dispersion, and the mixture was heated under reflux at 80°C with a magnetic stirrer for 1 hour. After the reaction was completed, the mixture was centrifuged and washed with anhydrous ethanol 3 times to remove the unloaded silane coupling agent on the surface of γ-Al2O3, and dried in an oven at 80°C for 24 hours, ground and dehydrated to obtain a modified γ-Al2O3;

[0074] (3) 0.2 g of dopamine hydrochloride was added to 100 mL of ethanol and ultrasonically dispersed; 0.5 g of modified γ-Al2O3 was added to the above solution, magnetically stirred and ultrasonically dispersed, and allowed to stand for 24 h. The supernatant was discarded and washed with anhydrous ethanol by centrifugation 6 times. The obtained product was dried in a vacuum drying oven at 60 ° C for 24 h to obtain an alumina composite;

[0075] (4) Weighing manganese dioxide, titanium dioxide, calcium oxide, and lanthanum oxide, and mixing them evenly to form a sintering aid;

[0076] The sintering aid includes: by weight: 2 parts of manganese dioxide, 1.5 parts of titanium dioxide, 1 part of calcium oxide, and 0.5 parts of lanthanum oxide;

[0077] Step 3: (1) 0.2 g of nanographene was added to 100 mL of anhydrous ethanol, and then 0.5 g of alumina composite was added to the above solution, ultrasonically dispersed for 6 h, vacuum dried and ground to obtain a composite powder, and the obtained composite powder was mixed and ground with a sintering aid (the amount of the sintering aid added accounted for 2 wt% of the composite powder), and ball milled for 8 h to obtain a raw material;

[0078] (2) heating the raw material to 200°C at a rate of 2°C / min and heat treating for 20 minutes; then heating to 1200°C at a rate of 4°C / min and calcining for 1 hour, then naturally cooling to 800°C and calcining for 3 hours to obtain calcined powder;

[0079] (3) Take 0.5 g of the calcined powder, add 100 mL of ethanol, mix and grind, ball mill for 48 h, and dry to obtain lanthanum-doped alumina composite grinding powder.

[0080] Experiment 1: The wear resistance of the abrasive powders prepared in Examples 1-3 and Comparative Examples 1-3 was tested. Experimental method: This experiment used a high-temperature friction and wear tester. 1 g of abrasive powder sample was weighed and placed in the high-temperature friction and wear tester. The load was set to 150 g and the test time was 5 minutes. After the test, the abrasive powder sample was weighed again. The wear resistance was calculated by calculating the weight loss before and after the test. The experimental results are shown in Table 1:

[0081] Table 1

[0082]

[0083]

[0084] Conclusion: The above experimental data show that the wear rate of the alumina grinding powder with added lanthanum in Example 2 of the present invention can reach 0.0393‰, and the wear rate of the alumina grinding powder without added lanthanum in Comparative Example 1 is 0.0581‰. Therefore, the addition of lanthanum can reduce the wear rate of the alumina grinding powder and improve the wear resistance of the grinding powder; the wear rate of the grinding powder with added nanographene and dopamine in Example 1 is 0.0412‰, the wear rate of the grinding powder without added nanographene in Comparative Example 2 is 0.0656‰, and the wear rate of the grinding powder without added dopamine in Comparative Example 3 is 0.0634‰. Therefore, the addition of nanographene and dopamine can improve the wear resistance because nanographene and dopamine can prevent the agglomeration of alumina powder, thereby reducing the viscosity of the slurry, uniformly dispersing the grinding powder particles, and achieving better grinding effect.

[0085] Experiment 2: Polishing experiments using abrasives were conducted using Example 1, Comparative Example 2, and Comparative Example 4. The polishing experiment was conducted on an automatic pressure grinding and polishing machine with a pressure of 5.0 kg, a carrier speed of 60 r / min, and a platen speed of 60 r / min for 1 minute. The polished sample was a sapphire wafer. After the experiment, the changes before and after polishing of the sample were measured using a balance, and the material removal rate was calculated. The surface roughness after polishing was then measured using an optical 3D surface profiler. The experimental results are shown in Table 2:

[0086] Table 2

[0087]

[0088]

[0089] Conclusion: The above experimental data show that in Comparative Example 2 of the present invention, 1μm molybdenum disulfide is selected to be added to the abrasive powder, and the material removal rate is 6.91μm / h, the surface roughness is 0.15μm, and the grinding rate is high, but the surface roughness of the material is high; in Comparative Example 4, 30nm nanographene is selected to be added to the abrasive powder, the material removal rate is 5.01μm / h, and the surface roughness is 0.09μm, which can be finely ground and significantly reduce the surface roughness of the material, but the grinding efficiency is low, so 1μm molybdenum disulfide and 30nm graphene are added to the abrasive powder at the same time and mixed, and the material removal rate of the mixed abrasive powder is 6.96μm / h, and the surface roughness of the material is 0.06μm, which can not only finely grind and reduce the surface roughness of the material, but also improve the grinding efficiency.

[0090] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for preparing lanthanum-doped alumina composite abrasive powder, characterized in that: The following steps are involved: Step 1: Add molybdenum disulfide to a Tris-HCl buffer solution, sonicate for 2 to 4 hours, add dopamine hydrochloride, stir for 12 to 14 hours, add ethanol, and disperse by sonication; add modified γ-Al2O3, disperse by sonication, let stand for 24 to 28 hours, discard the supernatant, centrifuge, wash, and dry for 24 to 26 hours to obtain a micronized molybdenum disulfide-alumina composite; Step 2: adding nanographene to anhydrous ethanol, then adding micronized molybdenum disulfide alumina composite, ultrasonically dispersing, vacuum drying, and grinding to obtain composite powder; mixing the composite powder with a sintering aid, grinding, and calcining to obtain calcined powder; Step 3: Add ethanol to the calcined powder, mix and grind, the ball milling time is 48 to 50 hours, and dry to obtain lanthanum-doped alumina composite grinding powder.

2. The method for preparing a lanthanum-doped alumina composite abrasive powder according to claim 1, wherein: The particle size of the nanographene is 30-40 nm.

3. The method for preparing a lanthanum-doped alumina composite abrasive powder according to claim 1, wherein: The preparation method of the modified γ-Al2O3 comprises the following steps: adding a silane coupling agent KH550 to deionized water, uniformly dispersing the mixture, and adding glacial acetic acid to adjust the pH to 3 to obtain a KH550 hydrolyzate; adding an ethanol aqueous solution to the γ-Al2O3, and ultrasonically dispersing the mixture to obtain a γ-Al2O3 dispersion; and adding the KH550 hydrolyzate to the γ-Al2O3 dispersion, heating the mixture under reflux, washing, drying, grinding, and dehydrating the mixture to obtain the modified γ-Al2O3.

4. The method for preparing a lanthanum-doped alumina composite abrasive powder according to claim 3, wherein: The preparation method of γ-Al2O3 comprises the following steps: placing aluminum hydroxide powder in an autoclave, hydrothermally treating the powder for 3 to 4 hours, washing, drying, and calcining the powder for 3 to 4 hours to obtain γ-Al2O3.

5. The method for preparing a lanthanum-doped alumina composite abrasive powder according to claim 4, characterized in that: The preparation method of the aluminum hydroxide powder comprises: uniformly mixing high-aluminum fly ash and sodium carbonate, calcining for 1 to 2 hours, coarsely grinding, acid leaching, and filtering; adjusting the pH value of the filtrate to 5 to generate a precipitate; filtering and washing the generated precipitate, dissolving the precipitate with a sodium hydroxide solution to a pH of 10, filtering, and washing to obtain a sodium aluminate solution; Carbon dioxide is introduced into the solution to generate aluminum hydroxide precipitate, which is then dried and ball-milled to obtain aluminum hydroxide powder.

6. The method for preparing a lanthanum-doped alumina composite abrasive powder according to claim 1, wherein: The sintering aid comprises the following substances: calculated by weight: 2 to 3 parts of manganese dioxide, 1.5 to 2.5 parts of titanium dioxide, 1 to 2 parts of calcium oxide, and 0.5 to 1.5 parts of lanthanum oxide.

7. The method for preparing a lanthanum-doped alumina composite abrasive powder according to claim 1, characterized in that: In step 2, the calcination method is: heating to 200-300°C at a rate of 2-4°C / min, and heat treating for 20-40 minutes; then heating to 1200-1400°C at a rate of 4-8°C / min, calcining for 1-2 hours, and naturally cooling to 800-810°C and calcining for 3-5 hours to obtain calcined powder.

8. Lanthanum-doped alumina composite abrasive powder prepared according to the method for preparing lanthanum-doped alumina composite abrasive powder according to any one of claims 1 to 7.

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