A method for preparing Al2O3 / TiC composite ceramic particles

Abstract

The application provides a preparation method of Al2O3 / TiC composite ceramic particles, which comprises the following steps: S1, mixing Al2O3 powder and TiO2 sol and then drying to obtain Al2O3 powder raw material; S2, mixing aluminum powder, liquid phenolic resin and TiC powder, solidifying and crushing to obtain TiC powder raw material; S3, ball-milling and mixing the Al2O3 powder raw material, the TiC powder raw material and a dextrin solution to obtain dry-pressed Al2O3 / TiC composite ceramic particle material; S4, molding the dry-pressed Al2O3 / TiC composite ceramic particle material, crushing and drying to obtain Al2O3 / TiC composite ceramic particle blanks; and S5, sintering the Al2O3 / TiC composite ceramic particle blanks in a protective atmosphere at a temperature of 1400-1450 DEG C to obtain the Al2O3 / TiC composite ceramic particles.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of Al2O3 / TiC composite ceramic particles, in particular to a preparation method of Al2O3 / TiC composite ceramic particles applied to the preparation of ceramic particle / iron-based composite wear-resistant materials, and belongs to the field of engineering ceramic preparation. BACKGROUND

[0002] The Al2O3 ceramic particles mainly comprise alpha-Al2O3, and about 1-10 wt% of a sintering aid is added, and the main phase composition of the sintered Al2O3 ceramic particles is corundum microcrystal. The Al2O3 ceramic particles have the characteristics of high thermal stability and high hardness, and are relatively ideal reinforcing materials of ceramic iron-based composite wear-resistant materials due to the low price.

[0003] At present, the preparation method of the Al2O3 ceramic particle / Fe-based composite wear-resistant material in the industry is mainly a melting and casting method, and the specific process is as follows: firstly, Al2O3 particles with a certain particle size are uniformly mixed and added with a special adhesive, and then a porous ceramic preform with a required shape is formed in a mold, the adhesive is solidified, and the mold is demolded to obtain a porous Al2O3 ceramic particle preform. Then, according to the service requirements of the composite wear-resistant material, the Al2O3 ceramic particle preform is fixed at a specified position of a sand mold, an iron alloy melt with a designed formula is poured into the sand mold, the molten iron fills the gaps between the Al2O3 ceramic particles through surface tension, and the Al2O3 ceramic particle / Fe-based composite material is obtained. The melting and casting method for preparing the Al2O3 ceramic particle / Fe-based composite wear-resistant material has the characteristics of relatively simple preparation process, and the method can be used to prepare large and complex-shaped Al2O3 ceramic particle / Fe-based composite material components. Al2O3 ceramic particles are usually used as reinforcing particles of the Fe-based composite material. Because the Al2O3 ceramic particles have high hardness, when the Al2O3 ceramic particles are used as the reinforcing particles of the Fe-based composite material, the composite material prepared by the Al2O3 ceramic particles can achieve good wear resistance under the condition of small impact load. However, the wettability of the Al2O3 ceramic particles and the molten iron is poor, and in the process of pouring the molten iron, large pores and cavities are easily generated due to the poor wetting of the molten iron and the ceramic preform, and the prepared Al2O3 ceramic particle / Fe-based composite material is usually lower than 150 MPa, which greatly affects the field and safety of the composite material. At present, the method for solving the problem is to coat a layer of metal Ni or metal Ti on the surface of the Al2O3 ceramic particles by using a chemical plating method or a physical vapor deposition method, but the process needs to add an additional plating process, the preparation cost of the plated Al2O3 ceramic particles is greatly increased, and the bonding interface between the metal film and the Al2O3 ceramic particles is physical bonding, the bonding force is poor, and in the service process of the composite material, the debonding is easily generated at the interface between the metal film and the Al2O3 ceramic particles, and the plated composite material has limited improvement in the bending strength. SUMMARY

[0004] The present application aims to provide an Al2O3 / TiC composite ceramic particle, by introducing a certain amount of TiC into Al2O3 ceramic particles, using the good wettability of TiC with molten iron, improving the wettability of Al2O3 / TiC composite ceramic particles with molten iron during the molten iron casting process, solving the problem of poor infiltration of molten iron and Al2O3 / TiC composite ceramic particles to produce large pores and cavities and other defects, and improving the bending strength of the composite material.

[0005] The present application is achieved by the following technical solutions:

[0006] A preparation method of an Al2O3 / TiC composite ceramic particle, comprising the following steps:

[0007] S1 mixing Al2O3 powder and TiO2 sol and drying to obtain Al2O3 powder raw material;

[0008] S2 mixing aluminum powder, liquid phenolic resin and TiC powder, solidifying and crushing to obtain TiC powder raw material;

[0009] S3 ball-milling and mixing Al2O3 powder raw material, TiC powder raw material and dextrin solution to obtain dry-pressed Al2O3 / TiC composite ceramic particle material;

[0010] S4 breaking and drying the dry-pressed Al2O3 / TiC composite ceramic particle material after molding to obtain Al2O3 / TiC composite ceramic particle body;

[0011] S5 sintering the Al2O3 / TiC composite ceramic particle body at a temperature of 1400-1450 DEG C in a protective atmosphere to obtain the Al2O3 / TiC composite ceramic particle. TiO2 in the Al2O3 / TiC composite ceramic particle can be reduced to trivalent iron during casting of iron alloy, thereby improving the wettability of iron alloy to aluminum oxide.

[0012] The Al2O3 / TiC composite ceramic particle is applied as a reinforcing particle to prepare a casting by bonding and casting an iron alloy.

[0013] In S1, the preparation method of the TiO2 sol comprises the following steps:

[0014] stirring and mixing titanate and alcohol, adding alkali, high-speed stirring and drying to obtain the TiO2 sol.

[0015] The titanate includes butyl titanate;

[0016] The alcohol includes ethanol;

[0017] The mass ratio of the butyl titanate and ethanol is 1:6-8;

[0018] The speed of the stirring mixing is 6000-8000r / min, and the time is 0.5-1h;

[0019] The base includes ammonia water, the pH value of the ammonia water is 10-12; the adding amount of the ammonia water is 3-5ml per 500ml of the butyl titanate ethanol solution;

[0020] The speed of the high-speed stirring is 6000-8000r / min, and the time is 3-4h.

[0021] In S1, the mass ratio of the TiO2 sol to the Al2O3 powder is 3-4:6-7

[0022] The average particle size of the Al2O3 powder is 1-3 microns.

[0023] The drying temperature is 60-80℃.

[0024] The mesh number of the aluminum powder is 400#;

[0025] The average particle size of the TiC powder is 3-5 microns;

[0026] The mass ratio of the aluminum powder, the liquid phenolic resin and the TiC powder is (3-5):(3-5):(90-94);

[0027] The curing temperature is 150℃;

[0028] The curing time is 1-2h.

[0029] The concentration of the dextrin solution is 40wt%;

[0030] The content of the Al2O3 powder in the dry pressing material of the Al2O3 / TiC composite ceramic particles is 60%-75%;

[0031] The content of the TiC powder in the dry pressing material of the Al2O3 / TiC composite ceramic particles is 20%-36%;

[0032] The content of the dextrin solution in the dry pressing material of the Al2O3 / TiC composite ceramic particles is 4-5%.

[0033] The ball milling time is 1-2h;

[0034] The ball milling speed is 60-80r / min;

[0035] The ball-to-material mass ratio of the ball milling is 1:1;

[0036] The grinding balls used in the ball milling include 30% of grinding balls with a diameter of 10 mm and 70% of grinding balls with a diameter of 6 mm.

[0037] The pressure of the die forming is 70-100 MPa.

[0038] The temperature of the drying is 70 DEG C.

[0039] The time of the drying is 6-8 h.

[0040] The protective atmosphere includes N2.

[0041] The sintering includes the steps of heating to 400-450 DEG C at a heating rate of 2-3 DEG C / min, holding for 0.5-1 h, and then heating to 1400-1450 DEG C at a heating rate of 3-5 DEG C / min, holding for 1.5-2 h.

[0042] Compared with the prior art, the application has the following advantages:

[0043] The Al2O3 / TiC composite ceramic particles prepared by the application have good wettability with molten iron, and the wettability of the particles with molten iron is obviously better than that of ordinary Al2O3 ceramic particles when the particles are used to prepare ceramic metal composite materials by a melting and casting method, thereby the problems of poor wettability of molten iron with the ceramic preform and large pores and cavities are solved, and the bending strength of the composite material is improved.

[0044] The Al2O3 / TiC composite ceramic particles are used as reinforcing particles, and water glass is used as a binder to prepare a porous ceramic particle preform, the preform is fixed at a specified position of a sand mold, and then a Mn13 iron alloy melt is poured into the sand mold, the pouring temperature is 1520 DEG C, after the casting is cooled, a ZTA / Fe-based composite material mechanical test strip is cut by a water jet cutter, the size of the test strip is 20x20x150 mm, the surface of the test strip is ground by a vertical grinding machine, the surface roughness Ra of the test strip is 0.2 microns, and then the tensile strength of the test strip is measured on a comprehensive mechanical testing machine, the average tensile strength of 5 mechanical test strips is 220 MPa.

[0045] As a comparison, a preform prepared by using ordinary Al2O3 is used to cast a Mn13 iron alloy melt at 1520 DEG C, after the casting is cooled, a ZTA / Fe-based composite material mechanical test strip is cut by a water jet cutter, the size of the test strip is 20x20x150 mm, the surface of the test strip is ground by a vertical grinding machine, the surface roughness Ra of the test strip is 0.2 microns, and then the tensile strength of the test strip is measured on a comprehensive mechanical testing machine, the average tensile strength of 5 mechanical test strips is 120 MPa. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1Al2O3 / TiC composite ceramic particles prepared in Example 1 after furnace cooling after holding at 1450℃ for 2h are shown. Figure 1 It is shown that black Al2O3 / TiC composite ceramic particles with certain particle size can be obtained after furnace cooling after holding at 1450℃ for 2h.

[0047] Figure 2 Metallographic photos of Al2O3 / TiC composite ceramic particles prepared in Example 1 after furnace cooling after holding at 1450℃ for 2h are shown. The photos show that the microstructure of the Al2O3 / TiC composite ceramic particles obtained after furnace cooling after holding at 1450℃ for 2h is dense, in which the black phase is TiC grains and the white phase is Al2O3 grains.

[0048] Figure 3 The interface wetting of Mn13 ferrous alloy to Al2O3 / TiC composite ceramic particles after casting Mn13 ferrous alloy melt at 1520℃ and cooling is shown for the Al2O3 / TiC composite ceramic particles prepared in Example 1. Figure 3 It is shown that the Mn13 ferrous alloy melt cast at 1520℃ produces obvious wetting on the surface of the Al2O3 / TiC composite ceramic particles, and the Al2O3 / TiC composite ceramic particles have good wettability with the Mn13 ferrous alloy melt.

[0049] Figure 4 The interface wetting of Mn13 ferrous alloy to Al2O3 ceramic particles after casting Mn13 ferrous alloy melt at 1520℃ and cooling is shown for the Al2O3 ceramic particles. Figure 4 It is shown that the Mn13 ferrous alloy melt cast at 1520℃ does not produce obvious wetting on the surface of the Al2O3 ceramic particles, and the Al2O3 ceramic particles have poor wettability with the Mn13 ferrous alloy melt.

[0050] Figure 5 The interface microstructure of Mn13 ferrous alloy and Al2O3 / TiC composite ceramic particles after casting Mn13 ferrous alloy melt at 1520℃ and cooling is shown for the Al2O3 / TiC composite ceramic particles prepared in Example 1. Figure 5 It is shown that the Mn13 ferrous alloy melt cast at 1520℃ produces good wetting on the surface of the Al2O3 / TiC composite ceramic particles, and the interface between the Al2O3 / TiC composite ceramic particles and the Mn13 ferrous alloy is dense and flat without any impurities and pores, and the Al2O3 / TiC composite ceramic particles have good wettability with the Mn13 ferrous alloy melt.

[0051] Figure 6 A porous ceramic particle preform prepared by using the Al2O3 / TiC composite ceramic particles prepared in Example 1 as reinforcing particles and water glass as adhesive is shown. Figure 6It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process.

[0052] Figure 7 It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process. Figure 7 It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process.

[0053] Figure 8 It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process.

[0054] Figure 9 It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process. Figure 9 It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process.

[0055] Figure 10 It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process. Figure 10 It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process.

[0056] Figure 11 It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process. Figure 11 It is shown that the Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature can be prepared by the process. DETAILED DESCRIPTION

[0057] The technical solution of the present application is a preparation method of Al2O3 / TiC composite ceramic particles, which comprises the following steps:

[0058] (1) Treatment of Al2O3 powder raw material

[0059] Titanium butylate and ethanol are mixed in a mass ratio of 1:6-8, high-speed stirring (6000-8000 rpm) for 0.5-1 hour, then 3-5 ml of ammonia water with a pH value of 10-12 is added dropwise per 500 ml of mixed solution, and high-speed stirring (6000-8000 rpm) is continued for 2-4 hours. TiO2sol is prepared by hydrolysis of titanium butylate. TiO2sol and 1-3 μm Al2O3 powder (industrial grade) are weighed in a mass ratio of (3-4):(6-7) respectively. The weighed raw materials are poured into a high-speed stirrer, high-speed stirring (6000-8000 rpm) is continued for 0.5-1 hour, the slurry is poured out and dried at 60-80 degrees, and then passed through a 250# screen to obtain the treated Al2O3 raw material.

[0060] (2) Treatment of TiC powder raw material

[0061] Aluminum powder (400#), liquid phenolic resin (industrial grade), and TiC powder (3-5 μm) are weighed in a mass ratio of (3-5):(3-5):(90-94) and poured into a double-S stirrer. After stirring for 1-2 hours, the mixed powder is poured out, solidified in a 150-degree oven for 1-2 hours, and then crushed. After passing the mixed powder through a 200# screen, it is vacuum-sealed and stored in a bag to complete the treatment of the TiC powder raw material.

[0062] (3) Preparation of Al2O3 / TiC composite ceramic particle dry-pressed material

[0063] The weight percentage formula of the Al2O3 / TiC composite ceramic particle dry-pressed material is as follows:

[0064] Step 1 treated Al2O3 powder 60%-75%;

[0065] Step 2 treated TiC powder 20%-36%;

[0066] 4-5% of 40wt% dextrin solution;

[0067] Weigh all the raw materials and pour them into a corundum ball mill jar with a diameter of 400 mm. Add corundum grinding balls at a ball-to-material mass ratio of 1:1, with 30% of the balls being 10 mm in diameter and 70% being 6 mm in diameter. The rotation speed of the ball mill jar is 60-80 r / min. After grinding the raw materials for 1-2 hours, remove them, pass them through a 60# sieve, seal them in bags, and store them to obtain dry-pressed Al2O3 / TiC multiphase ceramic particles.

[0068] (4) Forming of Al2O3 / TiC composite ceramic particles

[0069] Select specifications as Using a 100×100mm circular mold, weigh out the appropriate mass of Al2O3 / TiC multiphase ceramic particles for dry pressing and place them into the mold. Press the mold under a pressure of 70-100MPa for 2-3 minutes, then release the pressure and demold. Place the molded Al2O3 / TiC multiphase ceramic green body on a stainless steel plate and dry it in a 70℃ oven for 6-8 hours. Then, crush the dried ceramic green body with a mortar and pestle and pass it through a 12# sieve and a 36# sieve. Take the green body fragments that are below the 12# sieve and above the 36# sieve as the molded Al2O3 / TiC multiphase ceramic particle green body.

[0070] (5) Sintering of Al2O3 / TiC composite ceramic particles

[0071] The Al2O3 / TiC multiphase ceramic particle blank obtained in step 4 is spread evenly on a SiC shelf and placed in a controlled atmosphere furnace. Under a N2 protective atmosphere, the temperature is increased to 400-450℃ at a rate of 2-3℃ / min and held for 0.5-1 hour. Then, the temperature is increased to 1400-1450℃ at a rate of 3-5℃ / min and held for 1.5-2 hours. After the furnace is closed, the Al2O3 / TiC multiphase ceramic particles are allowed to cool naturally inside the furnace. When the furnace temperature is below 400℃, the furnace door is opened for cooling. When the temperature is below 70℃, the Al2O3 / TiC multiphase ceramic particles are removed from the furnace to obtain the finished Al2O3 / TiC multiphase ceramic particles.

[0072] The present invention will be further explained below:

[0073] (1) Preparation of titanium dioxide sol for adhesives

[0074] (1) Processing of Al2O3 powder raw materials

[0075] Butyl titanate and ethanol are mixed and stirred according to a certain mass ratio, then a certain amount of ammonia water with a certain pH value is added dropwise, and a stable TiO2sol is prepared by hydrolysis of butyl titanate. Al2O3powder and TiO2sol are weighed according to a certain mass ratio, and a uniform slurry is obtained after high-speed stirring, then the slurry is dried at 60-80 degrees to obtain Al2O3powder coated with TiO2gel on the surface of Al2O3particles. The TiO2gel coated on the surface of the Al2O3powder is converted into high-activity TiO2nanoparticles in the subsequent sintering process, which forms a solid solution with the Al2O3powder, causing distortion of the Al2O3lattice, activating the lattice, improving the sintering property of the Al2O3powder, and reducing the sintering temperature. Moreover, Ti4+in the TiO2nanoparticles can be reduced to Ti 3+ Thus generating surface vacancies, further improving surface activity.

[0076] (2) Treatment of TiC powder raw material

[0077] After the aluminum powder, liquid phenolic resin and TiC powder are stirred and mixed according to a certain mass ratio, the mixed powder is poured out, and after solidification of the liquid phenolic resin in a 150-degree oven for 1-2 hours, the aluminum powder and TiC powder are uniformly bonded together to prevent segregation of the aluminum powder and TiC powder during the subsequent mixing process. After the mixed powder is passed through a 200# screen, it is vacuum sealed and stored, completing the treatment of the TiC powder raw material. A small amount of aluminum powder is added to the TiC powder, which melts at a temperature higher than 660 degrees during the subsequent sintering process, filling the space between the TiC powder in the form of a liquid. At the sintering temperature, a small amount of TiC will dissolve in the aluminum liquid, and through the dissolution and precipitation mechanism of TiC, the aluminum liquid can promote the sintering of the TiC powder.

[0078] (3) Preparation of Al2O3 / TiC composite ceramic particle dry-pressed material

[0079] After the Al2O3powder treated in step 1 and the TiC powder treated in step 2 and the 40wt% dextrin solution are weighed according to a certain ratio, they are ball-milled and mixed uniformly, and the 40wt% dextrin solution is added as a temporary binder for dry pressing. After the raw material is passed through a 60# screen, it is sealed and stored to obtain the Al2O3 / TiC composite ceramic particle dry-pressed material.

[0080] (4) Forming of Al2O3 / TiC composite ceramic particles

[0081] A certain mass of dry-pressed Al2O3 / TiC composite ceramic particle material is put into a circular mold with a size of 100 mm x 100 mm x 50 mm, and is pressed at a pressure of 70-100 MPa, with a pressure holding time of 2-3 minutes, and then is released from pressure and demolded. The formed Al2O3 / TiC composite ceramic body is placed on a stainless steel plate and is dried in a 70°C oven for 6-8 hours. Since the formed material contains 4-5% of dextrin powder, the formed body has a certain strength after drying at 70°C. Then, the dried ceramic body is broken with a mortar and is sieved through a 12# sieve and a 36# sieve, respectively. The body particles that pass through the 12# sieve and are retained on the 36# sieve have a particle size of about 0.4-1.3 mm, and the Al2O3 / TiC composite ceramic particle body with a composite particle size is obtained.

[0082] (5) Sintering of Al2O3 / TiC composite ceramic particles

[0083] The Al2O3 / TiC composite ceramic particle body obtained in step 4 is spread on a SiC shelf plate, and is heated to 400-450°C at a heating rate of 2-3°C / min in a N2 protective atmosphere. At this temperature, the dextrin begins to decompose, and the temperature is kept for 0.5-1 hour. After the dextrin is completely decomposed, the temperature is further increased to 1400-1450°C at a heating rate of 3-5°C / min, and the temperature is kept for 1.5-2 hours. During the temperature keeping process, the Al2O3 micropowder with TiO2 particle coating and the TiO2 nanoparticles form a solid solution with the Al2O3 powder, which promotes the sintering of the Al2O3 powder to form Al2O3 grains. The molten aluminum fills between the TiC powder, and a small amount of TiC is dissolved in the molten aluminum. Through the dissolution and precipitation mechanism of TiC, the molten aluminum promotes the sintering of the TiC powder to form TiC grains. After the temperature keeping at 1400-1450°C for 1.5-2 hours, the Al2O3 / TiC composite ceramic particle body is sintered to form a dense Al2O3 / TiC composite ceramic particle (see Figure 1 , Figure 2 ). After the furnace is closed, the Al2O3 / TiC composite ceramic particles are naturally cooled in the furnace. When the furnace temperature is lower than 400°C, the furnace door is opened for cooling. When the temperature is lower than 70°C, the Al2O3 / TiC composite ceramic particles are taken out of the furnace, and the Al2O3 / TiC composite ceramic particle product is obtained.

[0084] Example 1

[0085] This example provides a method for preparing Al2O3 / TiC composite ceramic particles. The specific steps are as follows:

[0086] (1) Treatment of Al2O3 powder raw material

[0087] Butyl titanate and ethanol were mixed in a mass ratio of 1:7, stirred at a high speed of 8000 rpm for 1 hour, then 5 ml of ammonia water with a pH value of 10 was added dropwise per 500 ml of the mixed solution, and stirred at a high speed of 8000 rpm for 4 hours. TiO2sol was prepared by hydrolysis of butyl titanate. TiO2sol and 1 μm Al2O3powder (industrial grade) were weighed in a mass ratio of 4:6. The weighed raw materials were poured into a high-speed stirrer, stirred at a high speed of 8000 rpm for 0.5 hours, then the slurry was poured out, dried at 80 degrees, and passed through a 250# screen to obtain the treated Al2O3raw material.

[0088] (2) Treatment of TiC powder raw material

[0089] Aluminum powder (400#), liquid phenolic resin (industrial grade), and TiC powder (5 μm) were weighed in a mass ratio of 5:5:90, then poured into a double-S stirrer, stirred for 2 h, then the mixed powder was poured out, solidified in an oven at 150 degrees for 1 h, then broken, and the mixed powder was passed through a 200# screen, then vacuum sealed and stored, to complete the treatment of the TiC powder raw material.

[0090] (3) Preparation of Al2O3 / TiC composite ceramic particle dry-pressed material

[0091] The weight percentage formula of the Al2O3 / TiC composite ceramic particle dry-pressed material is as follows:

[0092] Step 1 treated Al2O3powder 60%;

[0093] Step 2 treated TiC powder 36%;

[0094] Pectin solution with a concentration of 40 wt% 4%;

[0095] The weighed raw materials were poured into a corundum ball mill pot, the ball mill pot had a diameter of 400 mm, corundum grinding balls were added in a ball-to-material mass ratio of 1:1, wherein the balls with a diameter of 10 mm accounted for 30%, and the balls with a diameter of 6 mm accounted for 70%. The rotation speed of the ball mill pot was 80 r / min. After the raw materials were ball milled for 2 h, they were taken out, passed through a 60# screen, then sealed and stored, to obtain the Al2O3 / TiC composite ceramic particle dry-pressed material.

[0096] (4) Molding of Al2O3 / TiC composite ceramic particles

[0097] The specifications of the Al2O3 / TiC composite ceramic particles were selected as follows: 100x100 circular mold, the corresponding mass of Al2O3 / TiC composite ceramic particles dry pressing material is weighed, put into the mold, pressurized at 100 MPa, pressure for 3 minutes, release pressure, demoulding, the formed Al2O3 / TiC composite ceramic body is placed on a stainless steel plate, put into a 70℃ oven for drying for 6 hours, then the dried ceramic body is broken with a mortar and then passed through 12# and 36# sieves respectively, the body fragments under 12# and on 36# are taken as the formed Al2O3 / TiC composite ceramic particle body.

[0098] (5) Sintering of Al2O3 / TiC composite ceramic particles

[0099] The Al2O3 / TiC composite ceramic particle body obtained in step 4 is spread on a SiC shelf plate and put into a controllable atmosphere furnace, heated to 400℃ at a heating rate of 3℃ / min under N2 protection, then heated to 1450℃ at a heating rate of 5℃ / min and kept for 2 hours, after the furnace is turned off, the Al2O3 / TiC composite ceramic particles are naturally cooled in the furnace, when the furnace temperature is lower than 400℃, the furnace door is opened for cooling, when the temperature is lower than 70℃, the Al2O3 / TiC composite ceramic particles are taken out of the furnace, and the Al2O3 / TiC composite ceramic particle product is obtained. Figure 1 The Al2O3 / TiC composite ceramic particles prepared in Example 1 after being cooled in the furnace at 1450℃ for 2h are shown. Figure 1 It is shown that black Al2O3 / TiC composite ceramic particles with certain particle size can be obtained after being cooled in the furnace at 1450℃ for 2h.

[0100] Figure 2 The metallographic photo of the Al2O3 / TiC composite ceramic particles prepared in Example 1 after being cooled in the furnace at 1450℃ for 2h is shown. The photo shows that the microstructure of the Al2O3 / TiC composite ceramic particles obtained after being cooled in the furnace at 1450℃ for 2h is dense, in which the black phase is TiC grains and the white phase is Al2O3 grains.

[0101] Figure 3 The interface wetting of Mn13 ferrous alloy on the Al2O3 / TiC composite ceramic particles prepared in Example 1 after the Mn13 ferrous alloy melt is cast at 1520℃ is shown. Figure 3 It is shown that the Mn13 ferrous alloy melt cast at 1520℃ has obvious wetting on the surface of the Al2O3 / TiC composite ceramic particles, and the Al2O3 / TiC composite ceramic particles have good wettability with the Mn13 ferrous alloy melt.

[0102] Figure 5The picture shows the interface microstructure of Mn13 ferrous alloy and Al2O3 / TiC composite ceramic particles after the Al2O3 / TiC composite ceramic particles prepared in Example 1 are casted in Mn13 ferrous alloy melt at 1520℃ and cooled. Figure 5 The picture shows that the Mn13 ferrous alloy melt casted at 1520℃ has good wettability to the surface of the Al2O3 / TiC composite ceramic particles, the interface between the Al2O3 / TiC composite ceramic particles and the Mn13 ferrous alloy is dense and flat, and there is no impurity or pore, which indicates that the Al2O3 / TiC composite ceramic particles have good wettability to the Mn13 ferrous alloy melt.

[0103] Figure 6 The picture shows that the Al2O3 / TiC composite ceramic particles prepared in Example 1 are used as reinforcing particles, and water glass is used as adhesive to prepare a porous ceramic particle preform. Figure 6 The picture shows that the process can be used to prepare an Al2O3 / TiC composite ceramic particle porous ceramic preform with certain strength at room temperature.

[0104] As a comparison, Figure 7 The picture shows that commercially available Al2O3 ceramic particles are used as reinforcing particles, and water glass is used as adhesive to prepare a porous ceramic particle preform. Figure 7 The picture shows that the process can be used to prepare an Al2O3 ceramic particle porous ceramic preform with certain strength at room temperature.

[0105] Figure 8 The picture shows that the Al2O3 / TiC composite ceramic particles prepared in Example 1 are used as reinforcing particles, and water glass is used as adhesive to prepare a porous ceramic particle preform, and the bonding of the Mn13 ferrous alloy and the porous ceramic preform prepared from the Al2O3 / TiC composite ceramic particles after the porous ceramic preform is casted in Mn13 ferrous alloy melt at 1520℃ and cooled. The picture shows that the molten iron has good wettability to the porous ceramic preform prepared from the Al2O3 / TiC composite ceramic particles, and there is no pore or poor infiltration defect in the castings.

[0106] Example 2

[0107] The embodiment provides a preparation method of Al2O3 / TiC composite ceramic particles. The specific steps are as follows:

[0108] (1) Treatment of Al2O3 powder raw material

[0109] Butyl titanate and ethanol were mixed in a mass ratio of 1:6, stirred at a high speed of 6000 rpm for 1 hour, then 4 ml of ammonia water with a pH value of 11 was added dropwise per 500 ml of the mixed solution, and stirred at a high speed of 6000 rpm for 4 hours, thereby preparing a TiO2sol by hydrolysis of butyl titanate. TiO2sol and 2 μm Al2O3 powder (industrial grade) were weighed in a mass ratio of 3:7. The weighed raw materials were poured into a high-speed stirrer, stirred at a high speed of 7000 rpm for 1 hour, then the slurry was poured out, dried at 80 degrees, and passed through a 250# screen to obtain the treated Al2O3 raw material.

[0110] (2) Treatment of TiC powder raw material

[0111] Aluminum powder (400#), liquid phenolic resin (industrial grade), and TiC powder (4 μm) were weighed in a mass ratio of 4:4:92, then poured into a double-S stirrer, stirred for 2 h, then the mixed powder was poured out, solidified in an oven at 150 degrees for 2 h, broken, and then the mixed powder was passed through a 200# screen and vacuum-sealed in a bag for storage, thereby completing the treatment of the TiC powder raw material.

[0112] (3) Preparation of Al2O3 / TiC composite ceramic particle dry-pressed material

[0113] The weight percentage formula of the Al2O3 / TiC composite ceramic particle dry-pressed material is as follows:

[0114] Step 1 treated Al2O3 powder 75%;

[0115] Step 2 treated TiC powder 20%;

[0116] Pectin solution with a concentration of 40 wt% 5%;

[0117] The weighed raw materials were poured into a corundum ball mill pot with a diameter of 400 mm, corundum grinding balls were added in a ball-to-material mass ratio of 1:1, wherein the balls with a diameter of 10 mm accounted for 30%, and the balls with a diameter of 6 mm accounted for 70%. The rotation speed of the ball mill pot was 80 r / min. After the raw materials were ball milled for 2 h, they were taken out, passed through a 60# screen, and then vacuum-sealed in a bag for storage, thereby obtaining the Al2O3 / TiC composite ceramic particle dry-pressed material.

[0118] (4) Molding of Al2O3 / TiC composite ceramic particles

[0119] The specifications of the Al2O3 / TiC composite ceramic particles were selected as follows: 100x100 circular mold, the corresponding mass of Al2O3 / TiC composite ceramic particles dry pressing material, into the mold, under the pressure of 90MPa pressure forming, pressure 3 minutes, pressure relief, demolding, Al2O3 / TiC composite ceramic green body after molding placed on a stainless steel plate, put into a 70℃ oven drying 6 hours, then the dried ceramic body with mortar broken after 12# sieve and 36# sieve, take 12# sieve and 36# sieve on the green body particles as the Al2O3 / TiC composite ceramic particles after molding.

[0120] (5) Al2O3 / TiC composite ceramic particles sintering

[0121] The Al2O3 / TiC composite ceramic particles green body obtained in step 4, spread on the SiC shelf board, put into a controllable atmosphere furnace, under the protection of N2 atmosphere, with the heating rate of 4℃ / min, heated to 400℃, and kept for 1 hour, then heated to 1450℃ with the heating rate of 4℃ / min, and kept for 1.5 hours. After the furnace was turned off, the Al2O3 / TiC composite ceramic particles were naturally cooled in the furnace. When the furnace temperature was lower than 400℃, the furnace door was opened for cooling. When the temperature was lower than 70℃, the Al2O3 / TiC composite ceramic particles were taken out of the furnace, and the Al2O3 / TiC composite ceramic particles were obtained.

[0122] The Al2O3 / TiC composite ceramic particles prepared in Example 2 have good interface wetting with Mn13 ferroalloy after casting Mn13 ferroalloy melt at 1520℃ and cooling. The interface between the Al2O3 / TiC composite ceramic particles and the Mn13 ferroalloy is dense and flat, and no impurities or pores are present.

[0123] Example 3

[0124] The present embodiment provides a preparation method of Al2O3 / TiC composite ceramic particles. The specific steps are as follows:

[0125] (1) Treatment of Al2O3 powder raw material

[0126] Titanium butylate and ethanol were mixed at a mass ratio of 1:8, high-speed stirring 7000r / min for 0.5 hours, then 3ml ammonia water with pH value of 12 was added dropwise according to the proportion of every 500ml mixed solution, and high-speed stirring 7000r / min for 4 hours. TiO2 sol was prepared by hydrolysis of titanium butylate. TiO2 sol and 1μm Al2O3 powder (industrial grade) were weighed according to the mass ratio of 4:6. The weighed raw materials were poured into a high-speed stirrer and stirred at 6000r / min for 1 hour. The slurry was dried at 80 degrees and then passed through a 250# sieve to obtain the treated Al2O3 raw material.

[0127] (2) Processing of TiC powder raw materials

[0128] Aluminum powder (400#), liquid phenolic resin (industrial grade), and TiC powder (3μm) were weighed in a mass ratio of 3:3:94 and poured into a double-S mixer. After stirring for 2 hours, the mixed powder was poured out and cured in a 150-degree oven for 1 hour. The mixture was then crushed, passed through a 200# sieve, and vacuum-sealed for storage, thus completing the processing of TiC powder raw materials.

[0129] (3) Preparation of dry-pressed Al2O3 / TiC multiphase ceramic particles

[0130] The weight percentage formulation of Al2O3 / TiC multiphase ceramic particles dry-pressed material is as follows:

[0131] 70% of the Al2O3 powder was treated in step 1;

[0132] Step 2 treatment of TiC powder 25%;

[0133] 5% of a 40wt% dextrin solution;

[0134] Weighed raw materials were poured into a corundum ball mill jar with a diameter of 400 mm. Corundum grinding balls were added at a ball-to-material mass ratio of 1:1, with 30% of the balls being 10 mm in diameter and 70% being 6 mm in diameter. The ball mill jar rotated at 80 r / min. After grinding the raw materials for 1 hour, they were removed, passed through a 60# sieve, sealed in bags, and stored to obtain dry-pressed Al2O3 / TiC multiphase ceramic particles.

[0135] (4) Forming of Al2O3 / TiC composite ceramic particles

[0136] Select specifications as A 100×100 circular mold was used to weigh out the corresponding mass of Al2O3 / TiC multiphase ceramic particles for dry pressing. The material was then placed into the mold and pressed under a pressure of 70MPa for 3 minutes. After pressing, the material was released and demolded. The formed Al2O3 / TiC multiphase ceramic green body was placed on a stainless steel plate and dried in a 70℃ oven for 6 hours. The dried ceramic green body was then crushed with a mortar and pestle and passed through a 12# sieve and a 36# sieve. The green body fragments that passed through the 12# sieve and the 36# sieve were taken as the formed Al2O3 / TiC multiphase ceramic particle green body.

[0137] (5) Sintering of Al2O3 / TiC composite ceramic particles

[0138] The Al2O3 / TiC composite ceramic particle blank obtained in step 4 is laid flat on a SiC shelf plate and placed in a controllable atmosphere furnace, heated to 450℃ at a heating rate of 3℃ / min under a N2protective atmosphere, and then heated to 1400℃ at a heating rate of 3℃ / min, and held for 2 hours. After the furnace is turned off, the Al2O3 / TiC composite ceramic particles are naturally cooled in the furnace. When the furnace temperature is lower than 400℃, the furnace door is opened to cool. When the temperature is lower than 70℃, the Al2O3 / TiC composite ceramic particles are taken out of the furnace to obtain the finished Al2O3 / TiC composite ceramic particles.

[0139] The Al2O3 / TiC composite ceramic particles prepared in Example 3 have good interface wetting with the Mn13 iron alloy after the Mn13 iron alloy melt is cast at 1520℃ and cooled. The interface between the Al2O3 / TiC composite ceramic particles and the Mn13 iron alloy is dense and flat, and no impurities or pores are present.

[0140] Comparative Example 1

[0141] The present embodiment provides a method for preparing Al2O3 / TiC composite ceramic particles. The specific steps are as follows:

[0142] (1) Treatment of TiC powder raw material

[0143] Aluminum powder (400#), liquid phenolic resin (industrial grade), and TiC powder (3-5μm) are weighed according to a mass ratio of 5:5:90, then poured into a double S mixer, stirred for 2h, and then poured out. The mixed powder is solidified in a 150-degree oven for 1h, then broken, and then the mixed powder is passed through a 200# sieve and vacuum sealed for storage. The treatment of the TiC powder raw material is completed.

[0144] (2) Preparation of Al2O3 / TiC composite ceramic particle dry-pressed material

[0145] The weight percentage formula of the Al2O3 / TiC composite ceramic particle dry-pressed material is as follows:

[0146] Commercially available Al2O3 powder 60%;

[0147] TiC powder treated in step 1 36%;

[0148] 4% of a 40wt% concentration of dextrin solution;

[0149] The weighed raw materials were poured into a corundum ball mill jar with a diameter of 400 mm. Corundum grinding balls were added at a ball-to-material mass ratio of 1:1, with 30% of the balls having a diameter of 10 mm and 70% having a diameter of 6 mm. The rotation speed of the ball mill jar was 80 r / min. After grinding the raw materials for 2 hours, they were removed, passed through a 60# sieve, sealed in bags, and stored to obtain dry-pressed Al2O3 / TiC multiphase ceramic particles.

[0150] (3) Forming of Al2O3 / TiC composite ceramic particles

[0151] Select specifications as A 100×100 circular mold was used to weigh out the corresponding mass of Al2O3 / TiC multiphase ceramic particles for dry pressing. The material was then placed into the mold and pressed under a pressure of 100MPa for 3 minutes. After pressing, the material was released and demolded. The formed Al2O3 / TiC multiphase ceramic green body was placed on a stainless steel plate and dried in a 70℃ oven for 6 hours. The dried ceramic green body was then crushed with a mortar and pestle and passed through a 12# sieve and a 36# sieve. The green body fragments that passed through the 12# sieve and the 36# sieve were taken as the formed Al2O3 / TiC multiphase ceramic particle green body.

[0152] (3) Sintering of Al2O3 / TiC composite ceramic particles

[0153] The Al2O3 / TiC multiphase ceramic particle blank obtained in step 4 is spread evenly on a SiC oven plate and placed in a controlled atmosphere furnace. Under a N2 protective atmosphere, the temperature is increased to 400°C at a rate of 3°C / min and held for 1 hour. Then, the temperature is increased to 1450°C at a rate of 5°C / min and held for 2 hours. After the furnace is closed, the Al2O3 / TiC multiphase ceramic particles are allowed to cool naturally inside the furnace. When the furnace temperature is below 400°C, the furnace door is opened for cooling. When the temperature is below 70°C, the Al2O3 / TiC multiphase ceramic particles are removed from the furnace to obtain the finished Al2O3 / TiC multiphase ceramic particles. Figure 10 The diagram shows the bonding of the porous ceramic preform prepared from Al2O3 / TiC composite ceramic particles as reinforcing particles and water glass as a binder. The preform was then cast at 1520℃ into a molten Mn13 ferroalloy and cooled to obtain the Mn13 ferroalloy. Figure 10 This indicates that due to the low surface energy, the porous ceramic preform prepared by molten iron and Al2O3 ceramic particles has poor wettability, resulting in defects such as porosity and poor impregnation in the casting.

[0154] Comparative Example 2

[0155] This embodiment provides a method for preparing Al2O3 / TiC composite ceramic particles. The specific steps are as follows:

[0156] (1) Processing of Al2O3 powder raw materials

[0157] Tetrabutyl titanate and ethanol were mixed at a mass ratio of 1:7 and stirred at high speed at 8000 rpm for 1 hour. Then, ammonia water with a pH of 10 was added dropwise at a ratio of 5 ml per 500 ml of the mixture, and the mixture was stirred at high speed at 8000 rpm for 4 hours. TiO2 sol was prepared by hydrolysis of tetrabutyl titanate. TiO2 sol and 1-3 μm Al2O3 powder (industrial grade) were weighed at a mass ratio of 4:6-7. The weighed raw materials were poured into a high-speed stirrer and stirred at high speed at 8000 rpm for 1 hour. The slurry was then dried at 80 degrees Celsius and passed through a 250# sieve to obtain the processed Al2O3 raw material.

[0158] (2) Preparation of dry-pressed Al2O3 / TiC multiphase ceramic particles

[0159] The weight percentage formulation of Al2O3 / TiC multiphase ceramic particles dry-pressed material is as follows:

[0160] 60% of the Al2O3 powder was treated in step 1;

[0161] Commercially available TiC powder contains 36%;

[0162] 4% of a 40 wt% dextrin solution;

[0163] The weighed raw materials were poured into a corundum ball mill jar with a diameter of 400 mm. Corundum grinding balls were added at a ball-to-material mass ratio of 1:1, with 30% of the balls having a diameter of 10 mm and 70% having a diameter of 6 mm. The rotation speed of the ball mill jar was 80 r / min. After grinding the raw materials for 2 hours, they were removed, passed through a 60# sieve, sealed in bags, and stored to obtain dry-pressed Al2O3 / TiC multiphase ceramic particles.

[0164] (3) Forming of Al2O3 / TiC composite ceramic particles

[0165] Select specifications as A 100×100 circular mold was used to weigh out the corresponding mass of Al2O3 / TiC multiphase ceramic particles for dry pressing. The material was then placed into the mold and pressed under a pressure of 100MPa for 3 minutes. After pressing, the material was released and demolded. The formed Al2O3 / TiC multiphase ceramic green body was placed on a stainless steel plate and dried in a 70℃ oven for 6 hours. The dried ceramic green body was then crushed with a mortar and pestle and passed through a 12# sieve and a 36# sieve. The green body fragments that passed through the 12# sieve and the 36# sieve were taken as the formed Al2O3 / TiC multiphase ceramic particle green body.

[0166] (4) Sintering of Al2O3 / TiC composite ceramic particles

[0167] The Al2O3 / TiC composite ceramic particle blank obtained in step 4 was laid flat on a SiC shelf plate and placed in a controllable atmosphere furnace. The furnace was heated to 400℃ at a heating rate of 3℃ / min under a N2 protective atmosphere, and then heated to 1450℃ at a heating rate of 5℃ / min, and held for 2 hours. After the furnace was turned off, the Al2O3 / TiC composite ceramic particles were naturally cooled in the furnace. When the temperature of the furnace was lower than 400℃, the furnace door was opened to cool the furnace. When the temperature was lower than 70℃, the Al2O3 / TiC composite ceramic particles were removed from the furnace, and the finished Al2O3 / TiC composite ceramic particles were obtained. Figure 11 The Al2O3 / TiC composite ceramic particles prepared in Comparative Example 2 were used as reinforcing particles, and water glass was used as a binder to prepare a porous ceramic preform. The bonding of the porous ceramic preform to the Mn13 ferrous alloy after the Mn13 ferrous alloy was cast from a melt at 1520℃ was observed. Figure 11 It was shown that the TiC sintering was poor, and the wettability of the molten iron with the porous ceramic preform prepared from Al2O3 ceramic particles was poor. Porosity and poor infiltration defects were observed in the castings.

Claims

1. A method for producing Al203 / TiC composite ceramic particles, characterized by: The method comprises the following steps: S1: mixing Al2O3 powder with TiO2 sol and drying to obtain Al2O3 powder raw material; S2: mixing aluminum powder, liquid phenolic resin and TiC powder, solidifying and crushing to obtain TiC powder raw material; S3: mixing Al2O3 powder raw material, TiC powder raw material and dextrin solution by ball milling to obtain Al2O3 / TiC composite ceramic particle dry pressing material; S4: molding the Al2O3 / TiC composite ceramic particle dry pressing material, crushing and drying to obtain Al2O3 / TiC composite ceramic particle blank; S5: sintering the Al2O3 / TiC composite ceramic particle blank in a protective atmosphere at a temperature of 1400-1450℃ to obtain the Al2O3 / TiC composite ceramic particle.

2. The method according to claim 1, wherein the preparation of the TiO2 sol comprises the following steps: S1: mixing titanium acid ester and alcohol, adding alkali, high-speed stirring and drying to obtain the TiO2 sol.

3. The method according to claim 2, wherein the titanium acid ester comprises butyl titanate; the alcohol comprises ethanol; the mass ratio of the butyl titanate to the ethanol is 1:6-8; the stirring speed is 6000-8000r / min and the stirring time is 0.5-1h; the alkali comprises ammonia water, the pH value of the ammonia water is 10-12, and the amount of the ammonia water added is 3-5ml per 500ml of the butyl titanate ethanol solution; the high-speed stirring speed is 6000-8000r / min and the high-speed stirring time is 3-4h.

4. The method according to claim 2, wherein the mass ratio of the TiO2 sol to the Al2O3 powder is 3-4:6-7; and the average particle size of the Al2O3 powder is 1-3 microns.

6. The method according to claim 1, wherein the mesh number of the aluminum powder is 400#; the average particle size of the TiC powder is 3-5 microns; the mass ratio of the aluminum powder, the liquid phenolic resin and the TiC powder is (3-5):(3-5):(90-94); the solidification temperature is 150℃; and the solidification time is 1-2h.

7. The method according to claim 1, wherein the concentration of the dextrin solution is 40wt%; the content of the Al2O3 powder in the Al2O3 / TiC composite ceramic particle dry pressing material is 60%-75%; the content of the TiC powder in the Al2O3 / TiC composite ceramic particle dry pressing material is 20%-36%; and the content of the dextrin solution in the Al2O3 / TiC composite ceramic particle dry pressing material is 4-5%. ​ ​ ​ ​ ​ ​ ​ 5. The method of claim 1, wherein the Al203 / TiC composite ceramic particles are prepared by the steps of: mixing Al203 and TiC powders; and sintering the mixed powders at a temperature of 1,400°C to 1,600°C for 1 to 5 hours in a vacuum or an inert gas atmosphere. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. The method of claim 1, wherein: the ball milling is performed for 1-2 hours; the ball milling is performed at a rotation speed of 60-80 r / min; the ball milling is performed with a ball-to-material mass ratio of 1:1; and the ball milling is performed using balls including 30% of balls having a diameter of 10 mm and 70% of balls having a diameter of 6 mm.

9. The method of claim 1, wherein: the die pressing is performed at a pressure of 70-100 MPa; the drying is performed at a temperature of 70°C; and the drying is performed for 6-8 hours.

10. The method of claim 1, wherein: the protective atmosphere includes N2; and the sintering includes heating at a heating rate of 2-3°C / min to 400-450°C, holding for 0.5-1 hour, and then heating at a heating rate of 3-5°C / min to 1400-1450°C, holding for 1.5-2 hours. ​ ​ ​ ​ ​ ​ ​ ​ ​

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