A method for preparing Al2O3 / Cr3C2 composite ceramic particles

Abstract

The present invention provides a method for preparing Al2O3 / Cr3C2 composite ceramic particles, comprising the following steps: S1 ball-milling a raw material of a sintering aid to obtain a smelting raw material; the raw material of the sintering aid comprises, by mass percentage, SiO2 70-74wt%, B2O3 10-12wt%, Na2CO3 10-12wt%, Fe2O3 3-5wt%, and TiO2 3‑5wt%; S2 heats the smelted raw material to 1500‑1550°C, holds the temperature, water quenches, and then ball mills to obtain a sintering aid powder; S3 mixes Al2O3 powder, Cr3C2 powder, sintering aid powder, and yellow dextrin powder, then ball mills the mixture, and sprays 5‑6% of the mass of water of the raw materials of the Al2O3 / Cr3C2 composite ceramic particles during the ball milling process to obtain a dry pressed material of the Al2O3 / Cr3C2 composite ceramic particles; S4 crushes the green body obtained by compression molding the dry pressed material of the Al2O3 / Cr3C2 composite ceramic particles, and then places the green body into step S2 for compression molding again to obtain a green body; S4 heats the green body to 400‑450°C, holds the temperature for 0.5‑1 hour, then heats the green body to 1300‑1350°C, holds the temperature for 1‑2 hours, then heats the green body to 1500‑1550°C, and holds the temperature for 1‑2 hours to obtain the green body.

Description

Technical Field

[0001] The present invention relates to a method for preparing Al2O3 / Cr3C2 composite ceramic particles, in particular to a method for preparing Al2O3 / Cr3C2 composite ceramic particles used for preparing ceramic particle / iron-based composite wear-resistant materials, belonging to the field of engineering ceramic preparation. Background Art

[0002] Wear is one of the three major ways that metal parts and mechanical equipment fail, along with abrasion, corrosion, and fatigue. In the fields of metallurgy, mining, coal, building materials, agricultural machinery, and electric power, many parts of crushing and grinding equipment, such as liners, hammers, and grinding balls, are subjected to intense wear from various abrasives such as ores and sand during operation. This causes severe wear and tear, which increases production costs. At present, in order to increase the service life of the above-mentioned wear parts, higher-hardness iron-based metal materials are often used to prepare such parts: such as high-chromium cast iron, alloy steel, high-manganese steel, and other materials. With the development of science and technology, the requirements for the service life of wear-resistant parts in industrial production are getting higher and higher. Single-phase iron-based wear-resistant materials can no longer meet the needs of industrial production in many application fields.

[0003] Compared with iron-based metal materials, ceramic materials have the characteristics of high hardness, good high-temperature stability, and stable chemical properties. In the past 30 years, the scientific community has conducted a large amount of research on ceramic particle-reinforced iron-based composite materials. The research results show that when a certain number of hard ceramic particles are compounded in the iron-based material, under certain wear conditions, the ceramic particles have a lower wear rate due to their higher hardness, and will gradually rise above the iron matrix at the working surface, thereby exerting a certain protective effect on the surrounding iron-based metal, thereby greatly improving the wear resistance of the composite material.

[0004] Currently, Al2O3 ceramic particle-reinforced iron-based composites are the most widely used ceramic / iron-based composite wear-resistant materials due to their relatively low raw material costs and excellent overall mechanical properties. The melt-casting method is the predominant method for preparing Al2O3 ceramic particle / Fe-based composite wear-resistant materials in industry due to its relatively simple process and the ability to produce large and complex Al2O3 ceramic particle / Fe-based composite components. The specific process is as follows: Al2O3 particles of a certain size are evenly mixed with a special adhesive and then formed into a porous ceramic preform of the desired shape in a mold. After the adhesive cures, the preform is demolded to obtain the porous Al2O3 ceramic particle preform. Then, depending on the service requirements of the composite wear-resistant material, the Al2O3 ceramic particle preform is fixed to a designated location in a sand mold. A specially formulated iron alloy melt is then poured into the sand mold. The molten iron, through surface tension, fills the spaces between the Al2O3 ceramic particles, resulting in the Al2O3 ceramic particle / Fe-based composite material.

[0005] The premise of using the casting infiltration method to prepare Al2O3 ceramic / Fe-based composite materials requires that the iron-based metal liquid can wet the Al2O3 ceramic particle preform. However, the iron-based metal material and the Al2O3 ceramic material are completely different in their composition and atomic bond structure. The bond structure of the iron-based metal is a metallic bond, while that of the Al2O3 ceramic is an ionic bond, and the electronic coordination is very stable. This leads to poor wettability between the iron-based metal and the Al2O3 ceramic. During the molten iron casting process, large pores and voids are generated due to poor infiltration of the molten iron and the Al2O3 ceramic particles. The prepared Al2O3 ceramic particle / Fe-based composite material is often lower than 150MPa, which greatly affects the application field and safety of the composite material.

[0006] Currently, the most mature industrial solution to this problem is to modify the surface of Al2O3 ceramic particles by coating them with a layer of metal elements such as Ni, Ti, and Cr. However, the addition of the surface modification step significantly increases the cost of preparing the coated Al2O3 ceramic particles. Furthermore, the interface between the metal film and the Al2O3 ceramic particles is physically bonded, resulting in poor bonding strength. Debonding is easily observed at this interface during the service life of the composite material, and the coating provides limited improvement in the composite material's flexural strength. Summary of the Invention

[0007] The present invention aims to design an Al2O3 / Cr3C2 composite ceramic particle. This composite ceramic particle is obtained by introducing a certain amount of Cr3C2 and a special sintering aid into the Al2O3 ceramic particle raw material formulation and sintering at high temperature. Because the composite ceramic particles contain a certain amount of Cr3C2 grains that exhibit good wettability with molten iron, the wettability of the composite ceramic particles with the molten iron is improved during the casting process. This addresses defects such as large pores and voids that occur in porous ceramic preforms prepared from the Al2O3 / Cr3C2 composite ceramic particles due to poor wetting between the molten iron and the composite ceramic particles, while also improving the flexural strength of the composite material.

[0008] The present invention is achieved through the following technical solutions:

[0009] A method for preparing Al2O3 / Cr3C2 composite ceramic particles comprises the following steps:

[0010] S1 ball-mills the raw materials of the sintering aid to obtain smelting raw materials;

[0011] The raw materials of the sintering aid include SiO2 70-74wt%, B2O3 10-12wt%, Na2CO3 10-12wt%, Fe2O3 3-5wt%, and TiO2 3-5wt% by mass percentage;

[0012] S2: heating the smelted raw materials to 1500-1550° C., keeping the temperature, and water quenching to obtain glass frit, and then ball milling to obtain sintering aid powder;

[0013] S3: mixing Al2O3 powder, Cr3C2 powder, sintering aid powder and yellow dextrin powder and then ball milling the mixture. During the ball milling process, 5-6% of water by weight of the raw materials of the Al2O3 / Cr3C2 composite ceramic particles is sprayed into the mixture to obtain a dry pressed material of the Al2O3 / Cr3C2 composite ceramic particles. S4: compression molding the dry pressed material and then crushing the material to obtain a green body of the Al2O3 / Cr3C2 composite ceramic particles.

[0014] S5: sintering the Al2O3 / Cr3C2 composite ceramic particle green body at 1300-1350° C. under a protective atmosphere to obtain Al2O3 / Cr3C2 composite ceramic particles; the Al2O3 / Cr3C2 composite ceramic particles are used as reinforcing particles, and after bonding, iron alloy is cast to prepare a casting.

[0015] The ball milling speed in S1 is 80-150 r / min;

[0016] The ball-to-material ratio of the ball mill in S1 is 1.2:1;

[0017] The ball milling time in S1 is 30-60 min.

[0018] The S2 includes the steps of heating the smelting raw material to 1000-1050° C. at a rate of 3-6° C. / min, and then heating the raw material to 1500-1550° C. at a rate of 4-5° C. / min.

[0019] The holding time in S2 is 2-3 hours.

[0020] The mass ratio of the balls, glass frit and pure water in the ball mill in S2 is 1.2:1:1.

[0021] The Al2O3 / Cr3C2 composite ceramic particle dry pressed material in S3 comprises, by weight percentage:

[0022] Al2O3 powder 60%-70%, Cr3C2 powder 20%-30%, sintering aid powder 5-7%, yellow dextrin powder 3-5%.

[0023] The ball-to-material mass ratio of the ball mill in S3 is 1:1;

[0024] The ball milling jar in S3 has a revolution speed of 60-80 r / min;

[0025] The rotation speed of the ball mill in S3 is 200-300 r / min.

[0026] The compression molding pressure is 100-150 MPa.

[0027] The protective atmosphere includes N2.

[0028] The sintering in S5 includes the steps of heating the Al2O3 / Cr3C2 composite ceramic particle body to 400-450°C at a heating rate of 2-3°C / min under a protective atmosphere and keeping the temperature for 0.5-1 hour.

[0029] The sintering in S5 also includes heating the Al2O3 / Cr3C2 composite ceramic particle body to 1300-1350°C at a heating rate of 3-5°C / min under a protective atmosphere, keeping the temperature for 1-2 hours, and then heating the Al2O3 / Cr3C2 composite ceramic particle body to 1500-1550°C at a heating rate of 3-5°C / min, and keeping the temperature for 1-2 hours.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The Al2O3 / Cr3C2 composite ceramic particles prepared by the present invention contain a certain amount of Cr3C2 grains with good wettability with molten iron. When a ceramic-metal composite material is prepared by a melt-casting method, the Al2O3 / Cr3C2 composite ceramic particles have good wettability with molten iron, which solves the problem of large pores and voids caused by poor infiltration of molten iron with the ceramic preform, while also improving the flexural strength of the composite material.

[0032] Al2O3 / Cr3C2 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 the sand mold, and then a Mn13 ferroalloy melt is poured into the sand mold at a casting temperature of 1520°C. After the casting is cooled, a water jet is used to cut ZTA / Fe-based composite material mechanical test bars with a size of 20×20×150mm. The surface of the test bars is ground using a vertical grinder with a surface roughness of Ra0.15-0.2μm. Then, its tensile strength is measured on a comprehensive mechanical testing machine. The average tensile strength of the five mechanical test bars is 260-280MPa.

[0033] In comparison, a preform prepared with ordinary Al2O3 was cast into a Mn13 ferroalloy melt at 1520°C. After the casting cooled, a water jet was used to cut ZTA / Fe-based composite mechanical test bars with a size of 20×20×150mm. The surface of the test bars was ground using a vertical grinder with a surface roughness Ra of 0.2μm. The tensile strength of the test bars was then measured on a comprehensive mechanical testing machine. The average tensile strength of the five mechanical test bars was 120MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1The figure shows the macroscopic morphology of the Al2O3 / Cr3C2 composite ceramic particles prepared in Example 1. The figure shows that the preparation method of the present invention can prepare Al2O3 / Cr3C2 composite ceramic particles with a certain diameter and irregular shape.

[0035] Figure 2 A crystal phase photograph of Al2O3 / Cr3C2 composite ceramic particles is shown. The image shows that the gray phase is Cr3C2, the dispersed white phase is Al2O3, and the locally agglomerated white phase is the sintering aid. The resulting Al2O3 / Cr3C2 composite ceramic particles have a dense structure.

[0036] Figure 3 The SEM image of the fracture surface of the Al2O3 / Cr3C2 composite ceramic particles prepared in Example 1 shows that the Al2O3 / Cr3C2 composite ceramic particles are composed of fine grains and have a dense structure, with no obvious pores observed.

[0037] Figure 4 The interface microstructure of the Mn13 ferroalloy and the Al2O3 / Cr3C2 composite ceramic particles in the composite material obtained by casting the Al2O3 / Cr3C2 composite ceramic particles prepared in Example 1 at 1520°C and cooling the Mn13 ferroalloy melt is shown. Figure 4 The results show that the Mn13 ferroalloy melt cast at 1520℃ has good wettability on the surface of Al2O3 / Cr3C2 composite ceramic particles. The interface between Al2O3 / TiC composite ceramic particles and Mn13 ferroalloy is dense and straight without any pores. A relatively obvious diffusion layer appears at the interface, which is beneficial to improving the wettability of Al2O3 / Cr3C2 composite ceramic particles and Mn13 ferroalloy melt.

[0038] Figure 5 A photo of a casting obtained by casting the Al2O3 / Cr3C2 composite ceramic particles prepared in Example 1 into a Mn13 ferroalloy melt at 1520°C and cooling it is shown. Figure 5 It shows that the porous ceramic preform prepared by molten iron and Al2O3 / Cr3C2 composite ceramic particles has good wettability, and no defects such as pores and poor infiltration occur in the casting.

[0039] Figure 6 The micrograph of the casting obtained by cooling the Mn13 ferroalloy melt cast at 1520℃ of Al2O3 / Cr3C2 composite ceramic particles prepared in Comparative Example 1 is shown. Figure 6 It can be seen that there are many pores in the casting.

[0040] Figure 7The micrograph of the casting obtained by cooling the Al2O3 / Cr3C2 composite ceramic particles prepared in Comparative Example 2 after casting the Mn13 ferroalloy melt at 1520°C is shown. Figure 7 It can be seen that there are many pores in the casting. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is a method for preparing Al2O3 / Cr3C2 composite ceramic particles, which comprises the following steps:

[0042] (1) Preparation of sintering aid

[0043] The raw material formula of the sintering aid (mass percentage wt%) is:

[0044]

[0045] Pour the weighed raw materials into a ball mill mixer at a rotation speed of 80-150 r / min, use 20 mm diameter corundum balls as the mixing medium, and a ball-to-material ratio of 1.2:1. After mixing for 30-60 minutes, pass through a 40# sieve to obtain the smelting raw materials.

[0046] The corundum crucible furnace is heated to 1000-1050°C at a rate of 3-6°C / min. A blocking rod is inserted and the mixed molten raw materials are poured in. When the raw material volume reaches 3 / 4 of the volume of the quartz crucible, the feeding is stopped and the temperature is raised to 1500-1550°C at a rate of 4-5°C / min. The temperature is kept at this temperature for 2-3 hours. A water tank is placed at the discharge port and filled with cold water. The blocking rod is lifted to allow the molten glass material to flow into the water tank for water quenching. The glass material fragments after water quenching are collected and poured into a corundum ball mill with a diameter of 400mm. Zirconia grinding balls and anhydrous ethanol are added in a mass ratio of 1.2:1:1 of balls, glass material, and pure water. The mass of the zirconia grinding balls is 50% by weight, and the mass of the 10mm diameter grinding balls is 50%. The ball mill rotates at a speed of 300-360r / min. After ball milling the raw materials for 8-12 hours, pour out the slurry, dry it at 80-100°C, and pass the dry powder through a 200# sieve to obtain the sintering aid powder.

[0047] (2) Preparation of dry pressed materials of Al2O3 / Cr3C2 phase ceramic particles

[0048] The weight percentage formula of Al2O3 / Cr3C2 composite ceramic particle dry pressing material is as follows:

[0049]

[0050]

[0051] The weighed raw materials were poured into a planetary mixer with a 250mm diameter ball mill. Corundum balls were added at a 1:1 ball-to-material ratio (50% 10mm diameter balls and 50% 5mm diameter balls). The mill was rotated at 60-80 rpm and 200-300 rpm. Water (5-6% by weight of the powder) was added by spraying during the mixing process. The raw materials were mixed for 1-2 hours before being removed from the mixer, passed through an 80# sieve, and sealed in a bag for 24 hours to obtain dry-pressed Al2O3 / Cr3C2 composite ceramic particles.

[0052] (3) Forming of Al2O3 / Cr3C2 composite ceramic particles

[0053] Select the specification A circular mold is prepared, and the corresponding mass of dry-pressed Al2O3 / Cr3C2 composite ceramic particles is weighed and placed in the mold. The dry-pressed Al2O3 / Cr3C2 composite ceramic particles are pressed and molded at a pressure of 100-150 MPa. After maintaining the pressure for 3-5 minutes, the pressure is released and the mold is released to obtain a round cake of dry-pressed Al2O3 / Cr3C2 composite ceramic particles. The formed round cake body is placed on a sieve and dried at room temperature for 12 hours. The dried round cake body is then crushed with a mortar and passed through an 8# sieve and a 15# sieve respectively. The green body particles under the 8# sieve and on the 15# sieve are taken as the formed Al2O3 / Cr3C2 composite ceramic particle green body. The particles under the 8# sieve and the 15# sieve are put back into the mixing process of step (2) and mixed with water, and then molded again.

[0054] (4) Sintering of Al2O3 / Cr3C2 composite ceramic particles

[0055] The Al2O3 / Cr3C2 composite ceramic particle body obtained in step (3) is spread flat on a SiC shelf, placed in a controlled atmosphere furnace, and heated to 400-450°C at a heating rate of 2-3°C / min under a N2 protective atmosphere, kept warm for 0.5-1 hour, then heated to 1300-1350°C at a heating rate of 3-5°C / min, kept warm for 1-2 hours, then heated to 1500-1550°C at a heating rate of 3-5°C / min, kept warm for 1-2 hours, and then the furnace is turned off. The Al2O3 / Cr3C2 composite ceramic particles are naturally cooled in the furnace to obtain finished Al2O3 / Cr3C2 composite ceramic particles.

[0056] The present invention will be further explained below:

[0057] (1) Preparation of sintering aid

[0058] The raw materials of the sintering aid are: SiO2, B2O3, Na2CO3, Fe2O3 and TiO2. After weighing a certain amount of raw materials according to the designed formula, the weighed raw materials are evenly mixed by ball milling to obtain smelting raw materials.

[0059] The corundum crucible furnace is heated at a constant rate to 1000-1050°C, the mixed raw materials are poured in, and then the temperature is raised to 1500-1550°C and held for 2-3 hours to melt the sintering aid. At the melting temperature, solid SiO2 melts into liquid, forming silicon-oxygen tetrahedra. Na2CO3 decomposes into Na2O, and B2O3 melts into planar borax triangular structures. Na2O provides free oxygen to the borax triangular structures, transforming them into borax tetrahedra. These borax tetrahedra and silicon-oxygen tetrahedra are connected by shared oxygen atoms, forming a three-dimensional glass network. During the melting process, Fe2O3 and TiO2 both incorporate into the glass network as octahedrons, forming a homogeneous liquid glass phase at the melting temperature. After melting, the sintering aid is water quenched to obtain a glass block, which is then ball-milled, dried, and sieved to obtain a sintering aid powder of a desired particle size.

[0060] (2) Preparation of dry pressed materials of Al2O3 / Cr3C2 composite ceramic particles

[0061] Al2O3 powder, Cr3C2 powder, sintering aid powder and yellow dextrin powder were weighed according to the formula and mixed evenly by ball milling. Dextrin liquid was added as a temporary adhesive for the dry pressed material. During the mixing process, a certain amount of water was added while mixing through the spray system of the mixer to make the molding material have a certain adhesion. After the raw materials passed through the 80# sieve, they were sealed in bags and stored for 24 hours to make the moisture of the molding material uniform, thereby obtaining the dry pressed material of Al2O3 / Cr3C2 composite ceramic particles.

[0062] (3) Forming of Al2O3 / Cr3C2 composite ceramic particles

[0063] A corresponding mass of dry-pressed Al2O3 / Cr3C2 composite ceramic particles is weighed and placed into a mold. Pressing is performed at a pressure of 100-150 MPa, and the pressure is maintained for 3-5 minutes before release and demolding to obtain a dry-pressed Al2O3 / Cr3C2 composite ceramic particle cake. The formed cake is placed on a screen and dried at room temperature for 12 hours. Due to the presence of 3-5% dextrin powder in the forming material, the dried cake has a certain strength. The dried cake is then crushed in a mortar and passed through an 8# sieve and a 15# sieve. The particles below the 8# sieve and above the 15# sieve are the formed Al2O3 / Cr3C2 composite ceramic particle green body. The particles have a particle diameter of approximately 1-2 mm, and the Al2O3 / Cr3C2 composite ceramic particle green body meets the required particle size combination.

[0064] (4) Sintering of Al2O3 / Cr3C2 composite ceramic particles

[0065] The Al2O3 / Cr3C2 composite ceramic particle body obtained in step 3 is spread flat on a SiC plate and heated to 400-450°C at a heating rate of 2-3°C / min in a N2 protective atmosphere. At this temperature, dextrin begins to decompose. The temperature is maintained for 0.5-1 hour until the dextrin decomposes. The temperature is then raised to 1300-1350°C at a heating rate of 3-5°C / min and maintained for 1-2 hours. At this temperature, the glass sintering aid softens and becomes a viscous fluid. The Na2O component in the sintering aid provides free oxygen to the Al2O3 fine powder in contact with the sintering aid, causing the Al2O3 to transform from aluminum oxide octahedra to aluminum oxide tetrahedra. The Al2O3 is partially dissolved in the sintering aid and precipitated in areas conducive to nucleation. At the same time, at this temperature, the Ti atoms in the TiO2 component in the sintering aid undergo a substitution reaction with some aluminum atoms on the surface of the Al2O3 powder, increasing the surface energy of the Al2O3 powder. Under the synergistic effect of the melting and precipitation effect of the Na2O component in the sintering aid and the replacement reaction of the TiO2 component, the alumina powder in the composite ceramic begins to sinter and form alumina grains. Then the temperature is raised to 1500-1550℃ at a heating rate of 3-5℃ / min. At this temperature, the radius of the Fe atoms in the Fe2O3 component in the sintering aid and the Cr atoms in the Cr3C2 are similar, and a replacement reaction can occur on the surface of the Cr3C2, increasing the surface lattice distortion of the Cr3C2 crystal and improving its sintering activity. At the same time, the Fe3+ in the Fe2O3 is easily changed under the action of the Cr3C2 with a certain degree of reduction at this temperature, forming Fe 2+ A large number of electrons freely pass through the interface between the molten sintering aid and the Cr3C2 powder, promoting the wetting of the sintering aid on the Cr3C2 powder. With the help of the molten sintering aid, the Cr3C2 powder is sintered to form Cr3C2 grains. In summary, the Al2O3 / Cr3C2 composite ceramic particle body of the present invention, with the help of the sintering aid, forms dense Al2O3 / Cr3C2 composite ceramic particles through secondary recrystallization of the Al2O3 powder and Cr3C2 powder during sintering.

[0066] The present application is further described below with reference to specific embodiments.

[0067] Example 1

[0068] This embodiment provides a method for preparing Al2O3 / Cr3C2 composite ceramic particles. The specific steps are as follows:

[0069] (1) Preparation of sintering aid

[0070] The raw material formula of the sintering aid (mass percentage wt%) is:

[0071]

[0072] Pour the weighed raw materials into a ball mill mixer at a rotation speed of 150 r / min. Use 20 mm diameter corundum balls as the mixing medium with a ball-to-material ratio of 1.2:1. After mixing for 30 minutes, pass through a 40# sieve to obtain the smelting raw materials.

[0073] The corundum crucible furnace was heated to 1050°C at a rate of 5°C / min, plugged with a blocking rod, and the mixed molten raw materials were poured in. When the raw material volume reached 3 / 4 of the volume of the quartz crucible, the feeding was stopped and the temperature was raised to 1500°C at a rate of 4°C / min. The temperature was kept at this temperature for 3 hours. A water tank was placed at the discharge port, cold water was poured in, and the blocking rod was lifted to allow the molten glass material to flow into the water tank for water quenching. The glass material fragments after water quenching were collected and poured into a corundum ball mill with a diameter of 400mm. Zirconia grinding balls and anhydrous ethanol were added in a mass ratio of 1.2:1:1 of balls, glass material, and pure water. The mass of the zirconia grinding balls accounted for 50% and the mass of the 10mm diameter grinding balls accounted for 50%. The ball mill rotated at a speed of 360r / min. After ball milling the raw materials for 12 hours, the slurry was poured out, dried at 100°C, and the dry powder was passed through a 200# sieve to obtain a sintering aid powder.

[0074] (2) Preparation of dry pressed materials of Al2O3 / Cr3C2 composite ceramic particles

[0075] The weight percentage formula of Al2O3 / Cr3C2 composite ceramic particle dry pressing material is as follows:

[0076]

[0077] The weighed raw materials were poured into a planetary mixer with a 250mm diameter ball mill. Corundum balls were added at a 1:1 ball-to-material ratio (50% 10mm diameter balls and 50% 5mm diameter balls). The mill was rotated at 80 rpm and 300 rpm. Water (5% by weight of the powder) was added by spraying during the mixing process. The raw materials were mixed for 1 hour, removed from the mixer, passed through an 80# sieve, and sealed in a bag for 24 hours to obtain dry-pressed Al2O3 / Cr3C2 composite ceramic particles.

[0078] (3) Forming of Al2O3 / Cr3C2 composite ceramic particles

[0079] Select the specification A circular mold is prepared, and the corresponding mass of dry-pressed molding material of Al2O3 / Cr3C2 composite ceramic particles is weighed and put into the mold. The dry-pressed molding material is pressed under a pressure of 150MPa, and the pressure is released and demolded after 3 minutes to obtain a dry-pressed molding material round cake of Al2O3 / Cr3C2 composite ceramic particles. The formed round cake green body is placed on a sieve and dried at room temperature for 12 hours. The dried round cake green body is then crushed with a mortar and passed through an 8# sieve and a 15# sieve respectively. The green body particles under the 8# sieve and on the 15# sieve are taken as the formed Al2O3 / Cr3C2 composite ceramic particle green body. The particles under the 8# sieve and the 15# sieve are put back into the mixing process of step (2) and mixed with water, and then molded again.

[0080] (4) Sintering of Al2O3 / Cr3C2 composite ceramic particles

[0081] The Al2O3 / Cr3C2 composite ceramic particle body obtained in step (3) was spread flat on a SiC shelf, placed in a controlled atmosphere furnace, and heated to 400°C at a heating rate of 2°C / min under a N2 protective atmosphere, kept warm for 0.5 hours, then heated to 1350°C at a heating rate of 5°C / min, kept warm for 1 hour, then heated to 1550°C at a heating rate of 5°C / min, kept warm for 2 hours, and then the furnace was turned off. The Al2O3 / Cr3C2 composite ceramic particles were naturally cooled in the furnace to obtain finished Al2O3 / Cr3C2 composite ceramic particles.

[0082] The Al2O3 / Cr3C2 composite ceramic particles prepared in Example 1 were used as reinforcing particles and water glass was used as an adhesive to prepare a porous ceramic particle preform. The preform was fixed at a specified position of the sand mold, and then a Mn13 ferroalloy melt was poured into the sand mold at a casting temperature of 1520°C. After the casting was cooled, a ZTA / Fe-based composite material mechanical test bar was cut using a water jet. The test bar size was 20×20×150 mm, and the test bar surface was ground using a vertical grinder. The test bar surface roughness Ra was 0.2 μm. Then, the tensile strength was measured on a comprehensive mechanical testing machine. The average tensile strength of the five mechanical test bars was 260 MPa.

[0083] Figure 1 The figure shows the macroscopic morphology of the Al2O3 / Cr3C2 composite ceramic particles prepared in Example 1. The figure shows that the preparation method of the present invention can prepare Al2O3 / Cr3C2 composite ceramic particles with a certain diameter and irregular shape.

[0084] Figure 2A crystal phase photograph of Al2O3 / Cr3C2 composite ceramic particles is shown. The image shows that the gray phase is Cr3C2, the dispersed white phase is Al2O3, and the locally agglomerated white phase is the sintering aid. The resulting Al2O3 / Cr3C2 composite ceramic particles have a dense structure.

[0085] Figure 3 The SEM image of the fracture surface of the Al2O3 / Cr3C2 composite ceramic particles prepared in Example 1 shows that the Al2O3 / Cr3C2 composite ceramic particles are composed of fine grains and have a dense structure, with no obvious pores observed.

[0086] Figure 4 The interface microstructure of the Mn13 ferroalloy and the Al2O3 / Cr3C2 composite ceramic particles in the composite material obtained by casting the Al2O3 / Cr3C2 composite ceramic particles prepared in Example 1 at 1520°C and cooling the Mn13 ferroalloy melt is shown. Figure 4 The results show that the Mn13 ferroalloy melt cast at 1520℃ has good wettability on the surface of Al2O3 / Cr3C2 composite ceramic particles. The interface between Al2O3 / TiC composite ceramic particles and Mn13 ferroalloy is dense and straight without any pores. A relatively obvious diffusion layer appears at the interface, which is beneficial to improving the wettability of Al2O3 / Cr3C2 composite ceramic particles and Mn13 ferroalloy melt.

[0087] Figure 5 A photo of a casting obtained by casting the Al2O3 / Cr3C2 composite ceramic particles prepared in Example 1 into a Mn13 ferroalloy melt at 1520°C and cooling it is shown. Figure 5 It shows that the porous ceramic preform prepared by molten iron and Al2O3 / Cr3C2 composite ceramic particles has good wettability, and no defects such as pores and poor infiltration occur in the casting.

[0088] Example 2

[0089] This embodiment provides a method for preparing Al2O3 / Cr3C2 composite ceramic particles. The specific steps are:

[0090] (1) Preparation of sintering aid

[0091] The raw material formula of the sintering aid (mass percentage wt%) is:

[0092]

[0093] Pour the weighed raw materials into a ball mill mixer at a rotation speed of 80 r / min. Use 20 mm diameter corundum balls as the mixing medium with a ball-to-material ratio of 1.2:1. After mixing for 60 minutes, pass through a 40# sieve to obtain the smelting raw materials.

[0094] The corundum crucible furnace was heated to 1050°C at a rate of 6°C / min, plugged with a blocking rod, and the mixed molten raw materials were poured in. When the raw material volume reached 3 / 4 of the volume of the quartz crucible, the feeding was stopped and the temperature was raised to 1550°C at a rate of 5°C / min. The temperature was kept at this temperature for 2 hours. A water tank was placed at the discharge port, cold water was poured in, and the blocking rod was lifted to allow the molten glass material to flow into the water tank for water quenching. The glass material fragments after water quenching were collected and poured into a corundum ball mill with a diameter of 400mm. Zirconia grinding balls and anhydrous ethanol were added in a ratio of 1.2:1:1 of balls, glass material, and pure water. The mass of the zirconia grinding balls accounted for 50% and the mass of the 10mm diameter grinding balls accounted for 50%. The ball mill rotated at a speed of 360r / min. After ball milling the raw materials for 12 hours, the slurry was poured out, dried at 100°C, and the dry powder was passed through a 200# sieve to obtain a sintering aid powder.

[0095] (2) Preparation of dry pressed materials of Al2O3 / Cr3C2 composite ceramic particles

[0096] The weight percentage formula of Al2O3 / Cr3C2 composite ceramic particle dry pressing material is as follows:

[0097]

[0098] The weighed raw materials were poured into a planetary mixer with a 250mm diameter ball mill. Corundum balls were added at a 1:1 ball-to-material ratio (50% 10mm diameter balls and 50% 5mm diameter balls). The mill was rotated at 80 rpm and 200 rpm. Water (5% by weight of the powder) was added by spraying during the mixing process. The raw materials were mixed for 1 hour, removed from the mixer, passed through an 80# sieve, and sealed in a bag for 24 hours to obtain dry-pressed Al2O3 / Cr3C2 composite ceramic particles.

[0099] (3) Forming of Al2O3 / Cr3C2 composite ceramic particles

[0100] Select the specification A circular mold is prepared, and the corresponding mass of dry-pressed molding material of Al2O3 / Cr3C2 composite ceramic particles is weighed and put into the mold. The dry-pressed molding material is pressed under a pressure of 1500MPa, and the pressure is released and demolded after 3 minutes to obtain a dry-pressed molding material round cake of Al2O3 / Cr3C2 composite ceramic particles. The formed round cake green body is placed on a sieve and dried at room temperature for 12 hours. The dried round cake green body is then crushed with a mortar and passed through an 8# sieve and a 15# sieve respectively. The green body particles under the 8# sieve and on the 15# sieve are taken as the formed Al2O3 / Cr3C2 composite ceramic particle green body. The particles under the 8# sieve and the 15# sieve are put back into the mixing process of step (2) and mixed with water, and then molded again.

[0101] (4) Sintering of Al2O3 / Cr3C2 composite ceramic particles

[0102] The Al2O3 / Cr3C2 composite ceramic particle body obtained in step (3) was spread flat on a SiC shelf, placed in a controlled atmosphere furnace, and heated to 450°C at a heating rate of 3°C / min under a N2 protective atmosphere, kept warm for 0.5 hours, then heated to 1350°C at a heating rate of 5°C / min, kept warm for 1 hour, then heated to 1500°C at a heating rate of 3°C / min, kept warm for 1 hour, and then the furnace was turned off. The Al2O3 / Cr3C2 composite ceramic particles were naturally cooled in the furnace to obtain finished Al2O3 / Cr3C2 composite ceramic particles.

[0103] The Al2O3 / Cr3C2 composite ceramic particles prepared in Example 2 were used as reinforcing particles and water glass was used as an adhesive to prepare a porous ceramic particle preform. The preform was fixed at a specified position of the sand mold, and then a Mn13 ferroalloy melt was poured into the sand mold at a casting temperature of 1520°C. After the casting was cooled, a ZTA / Fe-based composite material mechanical test bar was cut using a water jet. The test bar size was 20×20×150 mm, and the test bar surface was ground using a vertical grinder. The test bar surface roughness Ra was 0.18 μm. Then, its tensile strength was measured on a comprehensive mechanical testing machine. The average tensile strength of the five mechanical test bars was 270 MPa.

[0104] The Al2O3 / Cr3C2 composite ceramic particles prepared in Example 2 were cast at 1520°C and cooled from a Mn13 ferroalloy melt. No defects such as pores and poor infiltration were found in the castings.

[0105] Example 3

[0106] This embodiment provides a method for preparing Al2O3 / Cr3C2 composite ceramic particles. The specific steps are as follows:

[0107] (1) Preparation of sintering aid

[0108] The raw material formula of the sintering aid (mass percentage wt%) is:

[0109]

[0110]

[0111] Pour the weighed raw materials into a ball mill mixer at a rotation speed of 150 r / min. Use 20 mm diameter corundum balls as the mixing medium with a ball-to-material ratio of 1.2:1. After mixing for 60 minutes, pass through a 40# sieve to obtain the smelting raw materials.

[0112] The corundum crucible furnace was heated to 1000°C at a rate of 3°C / min, plugged with a blocking rod, and the mixed molten raw materials were poured in. When the raw material volume reached 3 / 4 of the volume of the quartz crucible, the feeding was stopped and the temperature was raised to 1550°C at a rate of 4°C / min. The temperature was kept at this temperature for 2 hours. A water tank was placed at the discharge port, cold water was poured in, and the blocking rod was lifted to allow the molten glass material to flow into the water tank for water quenching. The glass material fragments after water quenching were collected and poured into a corundum ball mill with a diameter of 400mm. Zirconia grinding balls and anhydrous ethanol were added in a ratio of 1.2:1:1 of balls, glass material, and pure water. The mass of the zirconia grinding balls accounted for 50% and the mass of the 10mm diameter grinding balls accounted for 50%. The ball mill rotated at a speed of 360r / min. After ball milling the raw materials for 12 hours, the slurry was poured out, dried at 100°C, and the dry powder was passed through a 200# sieve to obtain a sintering aid powder.

[0113] (2) Preparation of dry pressed materials of Al2O3 / Cr3C2 composite ceramic particles

[0114] The weight percentage formula of Al2O3 / Cr3C2 composite ceramic particle dry pressing material is as follows:

[0115]

[0116] The weighed raw materials were poured into a planetary mixer with a 250mm diameter ball mill. Corundum balls were added at a 1:1 ball-to-material ratio (50% 10mm diameter balls and 50% 5mm diameter balls). The mill was rotated at 60 rpm and 300 rpm. Water (5% by weight of the powder) was added by spraying during the mixing process. After mixing for 1 hour, the raw materials were removed, passed through an 80# sieve, and sealed in a bag for 24 hours to obtain dry-pressed Al2O3 / Cr3C2 composite ceramic particles.

[0117] (3) Forming of Al2O3 / Cr3C2 composite ceramic particles

[0118] Select the specification A circular mold is prepared, and the corresponding mass of dry-pressed molding material of Al2O3 / Cr3C2 composite ceramic particles is weighed and put into the mold. The dry-pressed molding material is pressed under a pressure of 150MPa, and the pressure is released and demolded after 3 minutes to obtain a dry-pressed molding material round cake of Al2O3 / Cr3C2 composite ceramic particles. The formed round cake green body is placed on a sieve and dried at room temperature for 12 hours. The dried round cake green body is then crushed with a mortar and passed through an 8# sieve and a 15# sieve respectively. The green body particles under the 8# sieve and on the 15# sieve are taken as the formed Al2O3 / Cr3C2 composite ceramic particle green body. The particles under the 8# sieve and the 15# sieve are put back into the mixing process of step (2) and mixed with water, and then molded again.

[0119] (4) Sintering of Al2O3 / Cr3C2 composite ceramic particles

[0120] The Al2O3 / Cr3C2 composite ceramic particle body obtained in step (3) was spread flat on a SiC shelf, placed in a controlled atmosphere furnace, and heated to 400°C at a heating rate of 2°C / min under a N2 protective atmosphere, kept warm for 0.5 hour, then heated to 1350°C at a heating rate of 5°C / min, kept warm for 0.5 hour, then heated to 1550°C at a heating rate of 5°C / min, kept warm for 2 hours, and then the furnace was turned off. The Al2O3 / Cr3C2 composite ceramic particles were naturally cooled in the furnace to obtain finished Al2O3 / Cr3C2 composite ceramic particles.

[0121] The Al2O3 / Cr3C2 composite ceramic particles prepared in Example 3 were used as reinforcing particles and water glass was used as an adhesive to prepare a porous ceramic particle preform. The preform was fixed at a specified position of the sand mold, and then a Mn13 ferroalloy melt was poured into the sand mold at a casting temperature of 1520°C. After the casting was cooled, a ZTA / Fe-based composite material mechanical test bar was cut using a water jet. The test bar size was 20×20×150 mm, and the test bar surface was ground using a vertical grinder. The test bar surface roughness Ra was 0.15 μm. Then, the tensile strength was measured on a comprehensive mechanical testing machine. The average tensile strength of the five mechanical test bars was 260 MPa.

[0122] The Al2O3 / Cr3C2 composite ceramic particles prepared in Example 3 were cast at 1520°C and cooled from a Mn13 ferroalloy melt. The castings did not show defects such as pores and poor infiltration.

[0123] Comparative Example 1

[0124] This embodiment provides a method for preparing Al2O3 / Cr3C2 composite ceramic particles. The specific steps are:

[0125] (1) Preparation of sintering aid

[0126] The raw material formula of the sintering aid (mass percentage wt%) is:

[0127]

[0128] Pour the weighed raw materials into a ball mill mixer at a rotation speed of 150 r / min. Use 20 mm diameter corundum balls as the mixing medium with a ball-to-material ratio of 1.2:1. After mixing for 60 minutes, pass through a 40# sieve to obtain the smelting raw materials.

[0129] The corundum crucible furnace was heated to 1050°C at a rate of 6°C / min, plugged with a blocking rod, and the mixed molten raw materials were poured in. When the raw material volume reached 3 / 4 of the volume of the quartz crucible, the feeding was stopped and the temperature was raised to 1550°C at a rate of 4°C / min. The temperature was kept at this temperature for 2 hours. A water tank was placed at the discharge port, cold water was poured in, and the blocking rod was lifted to allow the molten glass material to flow into the water tank for water quenching. The glass material fragments after water quenching were collected and poured into a corundum ball mill with a diameter of 400mm. Zirconia grinding balls and anhydrous ethanol were added in a ratio of 1.2:1:1 of balls, glass material, and pure water. The mass of the zirconia grinding balls accounted for 50% and the mass of the 10mm diameter grinding balls accounted for 50%. The ball mill rotated at a speed of 360r / min. After ball milling the raw materials for 12 hours, the slurry was poured out, dried at 100°C, and the dry powder was passed through a 200# sieve to obtain a sintering aid powder.

[0130] (2) Preparation of dry pressed materials of Al2O3 / Cr3C2 composite ceramic particles

[0131] The weight percentage formula of Al2O3 / Cr3C2 composite ceramic particle dry pressing material is as follows:

[0132]

[0133] The weighed raw materials were poured into a planetary mixer with a 250mm diameter ball mill. Corundum balls were added at a 1:1 ball-to-material ratio (50% 10mm diameter balls and 50% 5mm diameter balls). The mill was rotated at 80 rpm and 300 rpm. Water (5% by weight of the powder) was added by spraying during the mixing process. The raw materials were mixed for 1 hour, removed from the mixer, passed through an 80# sieve, and sealed in a bag for 24 hours to obtain dry-pressed Al2O3 / Cr3C2 composite ceramic particles.

[0134] (3) Forming of Al2O3 / Cr3C2 composite ceramic particles

[0135] Select the specification A circular mold is prepared, and the corresponding mass of dry-pressed molding material of Al2O3 / Cr3C2 composite ceramic particles is weighed and put into the mold. The dry-pressed molding material is pressed under a pressure of 150MPa, and the pressure is released and demolded after 3 minutes to obtain a dry-pressed molding material round cake of Al2O3 / Cr3C2 composite ceramic particles. The formed round cake green body is placed on a sieve and dried at room temperature for 12 hours. The dried round cake green body is then crushed with a mortar and passed through an 8# sieve and a 15# sieve respectively. The green body particles under the 8# sieve and on the 15# sieve are taken as the formed Al2O3 / Cr3C2 composite ceramic particle green body. The particles under the 8# sieve and the 15# sieve are put back into the mixing process of step (2) and mixed with water, and then molded again.

[0136] (4) Sintering of Al2O3 / Cr3C2 composite ceramic particles

[0137] The Al2O3 / Cr3C2 composite ceramic particle body obtained in step (3) was spread flat on a SiC shelf, placed in a controlled atmosphere furnace, and heated to 400°C at a heating rate of 2°C / min under a N2 protective atmosphere, kept warm for 0.5 hours, then heated to 1350°C at a heating rate of 5°C / min, kept warm for 1 hour, then heated to 1550°C at a heating rate of 5°C / min, kept warm for 2 hours, and then the furnace was turned off. The Al2O3 / Cr3C2 composite ceramic particles were naturally cooled in the furnace to obtain finished Al2O3 / Cr3C2 composite ceramic particles.

[0138] The Al2O3 / Cr3C2 composite ceramic particles prepared in Comparative Example 1 were used as reinforcing particles and water glass as an adhesive to prepare a porous ceramic particle preform. The preform was fixed at a designated position of the sand mold, and then a Mn13 ferroalloy melt was poured into the sand mold at a casting temperature of 1520°C. After the casting was cooled, a water jet was used to cut ZTA / Fe-based composite material mechanical test bars with a size of 20×20×150mm. The surface of the test bars was ground using a vertical grinder with a surface roughness of Ra0.39μm. The tensile strength was then measured on a comprehensive mechanical testing machine. The average tensile strength of the five mechanical test bars was 200MPa.

[0139] The Al2O3 / Cr3C2 composite ceramic particles prepared in Comparative Example 1 were cast from a Mn13 ferroalloy melt at 1520°C and cooled to obtain a casting that had defects such as pores and poor infiltration.

[0140] Comparative Example 2

[0141] This embodiment provides a method for preparing Al2O3 / Cr3C2 composite ceramic particles. The specific steps are as follows:

[0142] (1) Preparation of sintering aid

[0143] The raw material formula of the sintering aid (mass percentage wt%) is:

[0144]

[0145] Pour the weighed raw materials into a ball mill mixer at a rotation speed of 150 r / min. Use 20 mm diameter corundum balls as the mixing medium with a ball-to-material ratio of 1.2:1. After mixing for 60 minutes, pass through a 40# sieve to obtain the smelting raw materials.

[0146] The corundum crucible furnace was heated to 1050°C at a rate of 6°C / min, plugged with a blocking rod, and the mixed molten raw materials were poured in. When the raw material volume reached 3 / 4 of the volume of the quartz crucible, the feeding was stopped and the temperature was raised to 1550°C at a rate of 4°C / min. The temperature was kept at this temperature for 2 hours. A water tank was placed at the discharge port, cold water was poured in, and the blocking rod was lifted to allow the molten glass material to flow into the water tank for water quenching. The glass material fragments after water quenching were collected and poured into a corundum ball mill with a diameter of 400mm. Zirconia grinding balls and anhydrous ethanol were added in a ratio of 1.2:1:1 of balls, glass material, and pure water. The mass of the zirconia grinding balls accounted for 50% and the mass of the 10mm diameter grinding balls accounted for 50%. The ball mill rotated at a speed of 360r / min. After ball milling the raw materials for 12 hours, the slurry was poured out, dried at 100°C, and the dry powder was passed through a 200# sieve to obtain a sintering aid powder.

[0147] (2) Preparation of dry pressed materials of Al2O3 / Cr3C2 composite ceramic particles

[0148] The weight percentage formula of Al2O3 / Cr3C2 composite ceramic particle dry pressing material is as follows:

[0149]

[0150] The weighed raw materials were poured into a planetary mixer with a 250mm diameter ball mill. Corundum balls were added at a 1:1 ball-to-material ratio (50% 10mm diameter balls and 50% 5mm diameter balls). The mill was rotated at 80 rpm and 300 rpm. Water (5% by weight of the powder) was added by spraying during the mixing process. The raw materials were mixed for 1 hour, removed from the mixer, passed through an 80# sieve, and sealed in a bag for 24 hours to obtain dry-pressed Al2O3 / Cr3C2 composite ceramic particles.

[0151] (3) Forming of Al2O3 / Cr3C2 composite ceramic particles

[0152] Select the specification A circular mold is prepared, and the corresponding mass of dry-pressed molding material of Al2O3 / Cr3C2 composite ceramic particles is weighed and put into the mold. The dry-pressed molding material is pressed under a pressure of 150MPa, and the pressure is released and demolded after 3 minutes to obtain a dry-pressed molding material round cake of Al2O3 / Cr3C2 composite ceramic particles. The formed round cake green body is placed on a sieve and dried at room temperature for 12 hours. The dried round cake green body is then crushed with a mortar and passed through an 8# sieve and a 15# sieve respectively. The green body particles under the 8# sieve and on the 15# sieve are taken as the formed Al2O3 / Cr3C2 composite ceramic particle green body. The particles under the 8# sieve and the 15# sieve are put back into the mixing process of step (2) and mixed with water, and then molded again.

[0153] (4) Sintering of Al2O3 / Cr3C2 composite ceramic particles

[0154] The Al2O3 / Cr3C2 composite ceramic particle body obtained in step (3) was spread flat on a SiC shelf, placed in a controlled atmosphere furnace, and heated to 400°C at a heating rate of 2°C / min under a N2 protective atmosphere, kept warm for 0.5 hours, then heated to 1350°C at a heating rate of 5°C / min, kept warm for 1 hour, then heated to 1550°C at a heating rate of 5°C / min, kept warm for 2 hours, and then the furnace was turned off. The Al2O3 / Cr3C2 composite ceramic particles were naturally cooled in the furnace to obtain finished Al2O3 / Cr3C2 composite ceramic particles.

[0155] The Al2O3 / Cr3C2 composite ceramic particles prepared in Comparative Example 2 were used as reinforcing particles and water glass as an adhesive to prepare a porous ceramic particle preform. The preform was fixed at a specified position of the sand mold, and then a Mn13 ferroalloy melt was poured into the sand mold at a casting temperature of 1520°C. After the casting was cooled, a water jet was used to cut ZTA / Fe-based composite material mechanical test bars with a test bar size of 20×20×150mm. The surface of the test bar was ground using a vertical grinder with a surface roughness of Ra0.44μm. Then, its tensile strength was measured on a comprehensive mechanical testing machine. The average tensile strength of the 5 mechanical test bars was 208MPa.

[0156] The Al2O3 / Cr3C2 composite ceramic particles prepared in Comparative Example 2 were cast at 1520°C and cooled from a Mn13 ferroalloy melt. The castings had defects such as pores and poor infiltration.

Claims

1. A method for preparing Al2O3 / Cr3C2 composite ceramic particles, characterized in that: The steps include: S1 ball-mills the raw materials of the sintering aid to obtain smelting raw materials; The raw materials of the sintering aid include SiO2 70-74wt%, B2O3 10-12wt%, Na2CO3 10-12wt%, Fe2O3 3-5wt%, and TiO2 3-5wt% by mass percentage; S2: heating the smelted raw materials to 1500-1550° C., keeping the temperature, and water quenching to obtain glass frit, and then ball milling to obtain sintering aid powder; S3: mixing Al2O3 powder, Cr3C2 powder, sintering aid powder and yellow dextrin powder and then ball milling the mixture. During the ball milling process, 5-6% of water by weight of the raw materials of the Al2O3 / Cr3C2 composite ceramic particles is sprayed into the mixture to obtain a dry pressed material of the Al2O3 / Cr3C2 composite ceramic particles. S4: compression molding the dry pressed material and then crushing the material to obtain a green body of the Al2O3 / Cr3C2 composite ceramic particles. S5 sintering the Al2O3 / Cr3C2 composite ceramic particle green body at 1300-1350° C. under a protective atmosphere to obtain Al2O3 / Cr3C2 composite ceramic particles; The Al2O3 / Cr3C2 composite ceramic particles are used as reinforcing particles and are bonded and then cast into an iron alloy to prepare a casting.

2. The method for preparing Al2O3 / Cr3C2 composite ceramic particles according to claim 1, characterized in that: The ball milling speed in S1 is 80-150 r / min; The ball-to-material ratio of the ball mill in S1 is 1.2:1; The ball milling time in S1 is 30-60 min.

3. The method for preparing Al2O3 / Cr3C2 composite ceramic particles according to claim 1, wherein: The S2 includes the steps of heating the smelting raw material to 1000-1050° C. at a rate of 3-6° C. / min, and then heating the raw material to 1500-1550° C. at a rate of 4-5° C. / min.

4. The method for preparing Al2O3 / Cr3C2 composite ceramic particles according to claim 1, wherein: The holding time in S2 is 2-3h; The mass ratio of the balls, glass frit and pure water in the ball mill in S2 is 1.2:1:

1.

5. The method for preparing Al2O3 / Cr3C2 composite ceramic particles according to claim 1, wherein: The Al2O3 / Cr3C2 composite ceramic particle dry pressed material in S3 comprises, by weight percentage: Al2O3 powder 60%-70%, Cr3C2 powder 20%-30%, sintering aid powder 5-7%, yellow dextrin powder 3-5%.

6. The method for preparing Al2O3 / Cr3C2 composite ceramic particles according to claim 1, wherein: The ball-to-material mass ratio of the ball mill in S3 is 1:1 The ball milling jar in S3 has a revolution speed of 60-80 r / min; The rotation speed of the ball mill in S3 is 200-300 r / min.

7. The method for preparing Al2O3 / Cr3C2 composite ceramic particles according to claim 1, wherein: The compression molding pressure is 100-150 MPa.

8. The method for preparing Al2O3 / Cr3C2 composite ceramic particles according to claim 1, wherein: The protective atmosphere includes N2.

9. The method for preparing Al2O3 / Cr3C2 composite ceramic particles according to claim 1, wherein: The sintering in S5 includes the steps of heating the Al2O3 / Cr3C2 composite ceramic particle body to 400-450°C at a heating rate of 2-3°C / min under a protective atmosphere and keeping the temperature for 0.5-1 hour.

10. The method for preparing Al2O3 / Cr3C2 composite ceramic particles according to claim 9, characterized in that: The sintering in S5 also includes heating the Al2O3 / Cr3C2 composite ceramic particle body to 1300-1350°C at a heating rate of 3-5°C / min under a protective atmosphere, keeping the temperature for 1-2 hours, and then heating the Al2O3 / Cr3C2 composite ceramic particle body to 1500-1550°C at a heating rate of 3-5°C / min, and keeping the temperature for 1-2 hours.

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