A method for preparing a metal matrix ceramic composite material and a metal matrix ceramic composite material

Abstract

The application relates to a preparation method of a metal-based ceramic composite material and the metal-based ceramic composite material, and steps are as follows: 1. ceramic particle screening and pretreatment: screening and polishing are sequentially performed on the ceramic particles, and the Al2O3 and B4C powder mixture is uniformly sprayed on the surface of the polished ceramic particles in a thermal spraying mode; 2. ceramic preform preparation: after the pretreated ceramic particles, a bonding agent and a mixed powder are uniformly mixed, the mixture is filled into a mold, one-time solidification treatment is performed, a preliminarily formed ceramic preform is obtained, secondary solidification treatment is further performed, and the ceramic preform is obtained; 3. metal-based ceramic composite material pouring forming: the ceramic preform is placed in a casting cavity, metal liquid pouring is performed, and after cooling, the composite material is taken out; 4. heat treatment: the composite material is sequentially subjected to multi-stage normalizing heat treatment and tempering heat treatment, and the metal-based ceramic composite material is obtained. The application solves the problems of ceramic particle peeling and composite layer cracking of the existing composite material.

Description

Technical Field

[0001] This invention belongs to the field of wear-resistant materials technology, and in particular relates to a method for preparing a metal-based ceramic composite material and the metal-based ceramic composite material itself. Background Technology

[0002] Grinding equipment is essential in industries such as coal, metallurgy, mining, power, building materials, refractory materials, and energy for grinding various materials, including coal, sand, and soil. During this process, the core components of the grinding equipment—grind rollers and grinding disc liners—are subjected to the combined effects of the material's grinding force, the system's applied pressure, frictional resistance, and impact forces. Therefore, the service life of the grinding rollers and grinding disc liners directly determines the service life of the grinding equipment, and their material selection and manufacturing processes are subject to strict requirements.

[0003] Metal-based ceramic composites, as a new type of wear-resistant material, combine wear resistance and toughness. On the one hand, they rely on the high hardness and high stability of ceramic particles to resist the wear of materials, and on the other hand, they rely on the strong toughness of the metal matrix to protect the ceramic particles from the impact of materials. Their excellent wear resistance is gradually being demonstrated in the application process, and they are replacing traditional metal wear-resistant materials (such as high manganese steel and high chromium cast iron) and weld overlay composite metal materials.

[0004] Currently, the preparation of metal-based ceramic composites has achieved some results after years of research. However, due to the significant differences between ceramic materials and metal materials in terms of their inherent properties such as coefficient of thermal expansion, thermal conductivity, and surface wettability, the bonding effect between metal and ceramic materials is poor. Problems such as the lack of a transitional bonding layer and the presence of defects between the two lead to failures in practical use, including ceramic particle peeling and composite layer cracking, resulting in a service life that falls short of expectations. Chinese Patent Publication No. CN104439192A discloses a method for preparing honeycomb ceramic-metal composites using vertical mill rolling. This method only addresses two issues: the strength, porosity, and yield of ceramic preforms made from ceramic particles, and how to better fix the ceramic preforms within the casting cavity. Chinese Patent Publication No. CN103131969A discloses a ceramic mesh-reinforced metal-based composite preform and its preparation method. This method only addresses the overall macroscopic density and particle distribution uniformity of the ceramic preform made from ceramic particles. Chinese Patent Publication No. CN103769563A discloses a method for preparing a steel-based composite grinding roller and grinding disc reinforced with active element sintered ZTA particles. This method mainly improves interfacial wettability and bonding strength by adding active elements. However, the added active elements are one or a combination of Ni and Cr, and the direction of addition is incorrect, resulting in poor bonding effect between ZTA particles and the metal matrix, and even defects. Chinese Patent Publication No. CN103736549A discloses a method for preparing a metal-based ceramic composite grinding roller for a vertical mill. This method uses ceramic particles to replace ceramic blocks to produce ceramic preforms and subsequent metal-based ceramic composite materials, solving the problems of high brittleness and strong crack sensitivity that existed in the previous method of using large ceramic blocks to make metal composite materials.

[0005] In summary, current research on metal-based ceramic composites needs to address two key issues: first, achieving complete metal matrix coating of ceramic particles; and second, forming a metallurgical bonding transition layer between the metal and ceramic particles. This will allow both the ceramic and metal components in the composite to leverage their respective strengths, resulting in a composite material that combines wear resistance and toughness. Summary of the Invention

[0006] This invention addresses the problems of existing technologies by providing a method for preparing metal-based ceramic composite materials and the resulting metal-based ceramic composite material. This method is practical and reliable. The prepared ceramic composite preforms, when cast from molten metal to produce the metal-based ceramic composite material, ensure complete impregnation, fully coating the ceramic particles, and forming a metallurgical bonding transition layer between the ceramic particles and the metal. The composite material is free from defects such as cracks, voids, and inclusions, thus solving the problems of ceramic particle peeling and composite layer cracking in existing composite materials.

[0007] This invention is achieved through a method for preparing a metal-based ceramic composite material, with the following specific steps:

[0008] Step 1: Screening and pretreatment of ceramic particles

[0009] Step 11: Screen the ceramic particles by size to make the particle size as uniform as possible;

[0010] Step 12: Place the screened ceramic particles into a ball mill to grind the edges and corners of the ceramic particles;

[0011] Step 13: After grinding, the ceramic particles are uniformly sprayed with a mixture of Al2O3 and B4C powders using a thermal spraying method.

[0012] Step 2: Fabrication of ceramic preforms

[0013] Step 21: After the pre-treated ceramic particles, adhesive and mixed powder are mixed evenly, they are filled into the mold for making the preform and cured once. After the first curing, a preliminary ceramic preform is obtained.

[0014] Step 22: Place the pre-formed ceramic preform into a device with heating and pressurizing functions for secondary curing to obtain the ceramic preform.

[0015] Step 3: Casting and molding of metal-based ceramic composite materials

[0016] Step 31: Fix one or more ceramic preforms in the casting cavity;

[0017] Step 32: Pour the molten metal into the casting cavity, and after it has completely solidified and cooled, remove the resulting composite material.

[0018] Step 4, heat treatment

[0019] Step 41: Perform multi-stage normalizing heat treatment on the composite material;

[0020] Step 42: The composite material after normalizing heat treatment is subjected to tempering heat treatment to obtain a metal-based ceramic composite material. Preferably, in step 11, the ceramic particles are one or a mixture of several of the following in any proportion: zirconium corundum, alumina, silicon nitride, silicon carbide, boron carbide, titanium carbide, titanium boride, and tungsten carbide.

[0021] Preferably, in step 11, the particle size of the ceramic particles after screening is in the range of 1 to 5 mm.

[0022] Preferably, in step 12, the rotation speed of the ball mill is 50-120 r / min, and the grinding time is 1-2 hours.

[0023] Preferably, in step 13, the powder mixture of Al2O3 and B4C has a mesh size of 500 to 600 mesh, the weight of the powder mixture accounts for 1 to 3% of the weight of the ceramic particles to be sprayed, and the weight ratio of Al2O3 to B4C in the powder mixture is 1:3 to 1:1.

[0024] Preferably, in step 21, when the amount of pretreated ceramic particles is 100 parts by weight, the amount of binder is 4 to 10 parts by weight, and the amount of mixed powder is 2 to 10 parts by weight.

[0025] Preferably, in step 21, the adhesive is a mixture of sodium silicate and water, with a weight ratio of sodium silicate to water of 1:1 to 4:1.

[0026] Preferably, in step 21, the mixed powder is composed of Al2O3, B4C and Fe3O powders. The mesh size of Al2O3 and B4C powders is 600-800 mesh, the mesh size of Fe3O powder is 800-1000 mesh, the weight ratio of the sum of Al2O3 and B4C to Fe3O is 1:3 to 1:1, the weight ratio of Al2O3 to B4C is 1:1, and the main components of Fe3O are 0.7-0.8% C, 12-14% Cr, 28-30% Ni, and the balance Fe.

[0027] Preferably, in step 21, the first curing process is as follows: first, CO2 gas is passed through for 1 to 2 minutes, then the mold is removed and placed in an oven for 2 to 4 hours at a temperature of 50 to 100°C.

[0028] Preferably, in step 22, the secondary curing process is as follows: the device first heats up at a rate of 0.5–2 °C / min to 1000–1150 °C and holds for 30 min; then the device begins to cool down at a rate of 1–2 °C / min, holding at 850–880 °C. Simultaneously, the device applies a compressive stress of 100–200 kg to the initially formed ceramic preform, holds the pressure for 15 min, releases the pressure, and continues to cool down at a rate of 2–3 °C / min until room temperature is reached, at which point the ceramic preform is removed from the device.

[0029] Preferably, in step 31, when one or more ceramic preforms are fixedly placed in the casting cavity, the gap between two adjacent ceramic preforms is controlled at 5-10 mm, and the gap between the ceramic preform and the cavity wall is controlled at 20-30 mm.

[0030] Preferably, in step 32, the molten metal is high-alloy steel, high-manganese steel, or high-chromium cast iron.

[0031] Preferably, in step 32, the pouring temperature is controlled at 1500-1580℃ and the pouring speed is controlled at 6-10 kg / s.

[0032] Preferably, in step 41, the multi-stage normalizing heat treatment step is as follows:

[0033] (1) Place the composite material in a heating furnace and heat it to 1080-1100℃ at a heating rate of 50-70℃ / h. Hold it for 1 hour and then cool it to 50-80℃ to complete the first normalizing heat treatment.

[0034] (2) After the first normalizing heat treatment, the composite material is heated to 980-1020℃ in the furnace, kept at that temperature for 4 hours, and then taken out and cooled to room temperature to complete the second normalizing heat treatment.

[0035] Preferably, in step 42, the tempering heat treatment step is as follows: the composite material after normalizing heat treatment is placed in a heat treatment furnace for treatment, heated to 650°C at a heating rate not exceeding 50°C / h, and held at that temperature for 1 hour, then cooled to 200°C at a cooling rate not exceeding 30°C / h, and held at that temperature for 1.5 hours, and then taken out and air-cooled to room temperature to obtain the metal-based ceramic composite material.

[0036] The advantages and positive effects of this invention are:

[0037] 1. By screening the particle size of ceramic particles and controlling the proportion of particle size range, this invention effectively ensures the porosity between ceramic particles in the preform, allowing the molten metal to better penetrate into the preform and completely encapsulate the ceramic particles.

[0038] 2. This invention removes the sharp edges of ceramic particles by grinding them, thus avoiding the risk of stress concentration causing particle breakage and peeling during subsequent use.

[0039] 3. This invention, through thermal spraying of a mixture of Al2O3 and B4C powder onto the surface of ceramic particles, can effectively achieve metallurgical bonding between ceramic particles and high-temperature molten metal via the mixed powder. After cooling, a transitional bonding layer is formed, which significantly improves the bonding force between the metal and the ceramic. This effectively solves the problem that traditional metal-based ceramic particles are only mechanically bonded, and the particles are prone to peeling and failure during use.

[0040] 4. The ceramic preform of the present invention undergoes two curing processes during its production, which significantly improves the strength of the preform itself, preventing it from collapsing and breaking during the pouring of molten metal. This effectively ensures that the ceramic particles are dispersed in their original positions, resulting in excellent wear resistance.

[0041] 5. The addition of powder composed of Al2O3, B4C and Fe3O to the ceramic preform of the present invention can actively help the molten metal to coat the ceramic particles, and can also effectively promote the formation of a metallurgical bonding transition layer between the molten metal and the ceramic particles.

[0042] 6. The heat treatment in this invention can effectively eliminate the casting residual stress generated in the composite material during the casting process and eliminate the cracking problem of the composite layer. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of the ceramic preform prepared in Example 1 of the present invention;

[0044] Figure 2 This is a scanning electron microscope micrograph of the composite region of metal and ceramic particles in the metal-based ceramic composite material prepared in Example 1 of the present invention;

[0045] Figure 3 yes Figure 2 Energy dispersive spectroscopy (EDS) results of the medium-sized metal matrix;

[0046] Figure 4 yes Figure 2 Energy dispersive spectroscopy (EDS) results of the ceramic matrix;

[0047] Figure 5 yes Figure 2 Energy dispersive spectroscopy (EDS) results of the transition layer between the metal and ceramic. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, and to further understand the invention's content, features, and effects, the following specific embodiments are provided to further illustrate the invention in detail. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0049] This embodiment provides a method for preparing a metal-based ceramic composite material, the specific steps of which are as follows:

[0050] Step 1: Screening and pretreatment of ceramic particles

[0051] Step 11: Screen the ceramic particles by size to make the particle size as uniform as possible;

[0052] Step 12: Place the screened ceramic particles into a ball mill to grind the edges and corners of the ceramic particles;

[0053] Step 13: After grinding, the ceramic particles are uniformly sprayed with a mixture of Al2O3 and B4C powders using a thermal spraying method.

[0054] Step 2: Fabrication of ceramic preforms

[0055] Step 21: After the pre-treated ceramic particles, adhesive and mixed powder are mixed evenly, they are filled into the mold for making the preform and cured once. After the first curing, a preliminary ceramic preform is obtained.

[0056] Step 22: Place the pre-formed ceramic preform into a device with heating and pressurizing functions for secondary curing to obtain the ceramic preform.

[0057] Step 3: Casting and molding of metal-based ceramic composite materials

[0058] Step 31: According to the actual requirements of the workpiece, fix one or more ceramic preforms in the casting cavity;

[0059] Step 32: Pour the molten metal into the casting cavity, and after it has completely solidified and cooled, remove the resulting composite material.

[0060] Step 4, heat treatment

[0061] Step 41: Perform multi-stage normalizing heat treatment on the composite material;

[0062] Step 42: The composite material after normalizing heat treatment is subjected to tempering heat treatment to obtain a metal matrix ceramic composite material.

[0063] In step 11, the ceramic particles are one or a mixture of several of the following in any proportion: zirconium corundum, alumina, silicon nitride, silicon carbide, boron carbide, titanium carbide, titanium boride, and tungsten carbide. Preferably, the ceramic particles in step 11 are a mixture of zirconium corundum, silicon carbide, and silicon nitride in any proportion. More preferably, the ceramic particles in step 11 are a mixture of zirconium corundum and silicon carbide in any proportion.

[0064] In step 11, the particle size of the ceramic particles after screening ranges from 1 to 5 mm. More preferably, the particle size of the ceramic particles after screening ranges from 2.5 to 4.5 mm, wherein the proportion of ceramic particles with a particle size of 2.5 to 4 mm is not less than 80%.

[0065] In step 12, the ball mill rotates at a speed of 50–120 r / min, and the grinding time is 1–2 hours.

[0066] In step 13, the powder mixture of Al2O3 and B4C has a mesh size of 500 to 600 mesh, the weight of the powder mixture accounts for 1 to 3% of the weight of the ceramic particles to be sprayed, and the weight ratio of Al2O3 to B4C in the powder mixture is 1:3 to 1:1.

[0067] In step 21, the amounts of pretreated ceramic particles, binder, and mixed powder are determined based on the weight of the ceramic particles. When the amount of pretreated ceramic particles is 100 parts by weight, the amount of binder is 4-10 parts by weight, and the amount of mixed powder is 2-10 parts by weight. The binder is a mixture of sodium silicate and water, with a weight ratio of sodium silicate to water of 1:1 to 4:1. The mixed powder is a mixture of Al2O3, B4C, and Fe3O powders. The mesh sizes of Al2O3 and B4C powders are 600-800 mesh, and the mesh size of Fe3O powder is 800-1000 mesh. The weight ratio of the sum of Al2O3 and B4C to Fe3O is 1:3 to 1:1, and the weight ratio of Al2O3 to B4C is 1:1. The main components of Fe3O are 0.7-0.8% C, 12-14% Cr, 28-30% Ni, and the balance Fe.

[0068] In step 21, the first curing process is as follows: first, CO2 gas is passed through for 1 to 2 minutes to give it a certain strength, then the mold is removed and placed in a drying room for 2 to 4 hours at a temperature of 50 to 100°C.

[0069] In step 22, the secondary curing process is as follows: the device first heats up at a rate of 0.5–2 °C / min to 1000–1150 °C and holds for 30 min. Then, the device begins to cool down at a rate of 1–2 °C / min, holding at 850–880 °C. Simultaneously, the device applies a compressive stress of 100–200 kg to the pre-formed ceramic preform, holds the pressure for 15 min, releases the pressure, and continues cooling at a rate of 2–3 °C / min until room temperature is reached. The ceramic preform is then removed from the device. Preferably, during the heating process, the heating rate is controlled at 1–2 °C / min below 600 °C and at 0.5–1 °C / min above 600 °C.

[0070] In step 31, when one or more ceramic preforms are fixedly placed in the casting cavity, the gap between two adjacent ceramic preforms is controlled at 5-10 mm, and the gap between the ceramic preform and the cavity wall is controlled at 20-30 mm.

[0071] In step 32, the molten metal is high-alloy steel, high-manganese steel, or high-chromium cast iron. Preferably, the molten metal is high-alloy steel, with the main components being 0.3–0.6% C, 23–27% Cr, 1–1.5% Mo, 1–2% W, 0.5–1% Ti, and the balance Fe. During casting, the casting temperature is controlled at 1500–1580℃, and the casting speed is controlled at 6–10 kg / s.

[0072] In step 41, the multi-stage normalizing heat treatment process is as follows:

[0073] (1) Place the composite material in a heating furnace and heat it to 1080-1100℃ at a heating rate of 50-70℃ / h. Hold it for 1 hour and then cool it to 50-80℃ to complete the first normalizing heat treatment.

[0074] (2) After the first normalizing heat treatment, the composite material is heated to 980-1020℃ in the furnace, kept at that temperature for 4 hours, and then taken out and cooled to room temperature to complete the second normalizing heat treatment.

[0075] Preferably, the cooling method is oil cooling or air cooling. More preferably, when air cooling is used, the heating rate does not exceed 50℃ / h during the heating process; when oil cooling is used, the heating rate does not exceed 50℃ / h below 700℃ and does not exceed 30℃ / h above 700℃ during the heating process.

[0076] In step 42, the tempering heat treatment process is as follows: the normalized composite material is placed in a heat treatment furnace and heated to 650°C at a heating rate not exceeding 50°C / h, and held at that temperature for 1 hour. Then, it is cooled to 200°C at a cooling rate not exceeding 30°C / h, and held at that temperature for 1.5 hours. After cooling to room temperature, the composite material is obtained by air cooling. Before placing the normalized composite material into the heat treatment furnace, the initial temperature of the heat treatment furnace should not exceed 100°C.

[0077] Example 1

[0078] This embodiment 1 provides a method for preparing a metal-based ceramic composite material, the specific steps of which are as follows:

[0079] Step 1: Screening and pretreatment of ceramic particles

[0080] Step 11: Screen the particle size of the zirconium corundum ceramic particles. The particle size range after screening is 2.5-3 mm, of which the proportion of ceramic particles with a particle size of 2.5-2.7 mm is not less than 90%.

[0081] Step 12: Place the screened zirconium corundum ceramic particles into a ball mill to grind the edges and corners of the ceramic particles. Set the speed of the ball mill to 100 rpm and the grinding time to 1.5 hours.

[0082] Step 13: Weigh out 100 parts by weight of the polished zirconium corundum ceramic particles, weigh out 1 part by weight of 550 mesh Al2O3 powder, weigh out 1 part by weight of 550 mesh B4C powder, mix the Al2O3 and B4C powder evenly, and use thermal spraying to evenly spray the powder mixture onto the ceramic particles.

[0083] Step 2: Fabrication of ceramic preforms

[0084] Step 21: Weigh out 100 parts by weight of pretreated zirconium corundum ceramic particles; weigh out 4 parts by weight of sodium silicate and 1 part by weight of water, and mix the sodium silicate and water evenly to make 5 parts by weight of binder; weigh out 1 part by weight of 650-mesh Al2O3 powder, 1 part by weight of 650-mesh B4C powder, and 3 parts by weight of 850-mesh Fe3O powder, and mix the Al2O3, B4C, and Fe3O powder evenly to make 5 parts by weight of mixed powder; then, after evenly mixing the 100 parts by weight of pretreated ceramic particles, 5 parts by weight of binder, and 5 parts by weight of mixed powder, fill the mold for making the preform and perform a first curing treatment; the first curing treatment process is as follows: first, pass CO2 gas for 1 minute, remove the mold, and place it in the drying room for 4 hours, with the drying room temperature set at 60℃; after the first curing treatment, a preliminary ceramic preform is obtained.

[0085] Step 22: The pre-formed ceramic preform is placed in a device with heating and pressurizing functions for secondary curing. The secondary curing process is as follows: the device first heats the preform to 600℃ at a rate of 1℃ / min, then heats it to 1100℃ at a rate of 0.5℃ / min, holds it at that temperature for 30 minutes, then cools it down to 880℃ at a rate of 1℃ / min and holds it there. Simultaneously, the device applies a compressive stress of 150 kg to the pre-formed ceramic preform, holds the pressure for 15 minutes, then releases the pressure. After releasing the pressure, the device cools down to room temperature at a rate of 2℃ / min, completing the fabrication of the ceramic preform. The structure of the ceramic preform is as follows: Figure 1 As shown.

[0086] Step 3: Casting and molding of metal-based ceramic composite materials

[0087] Step 31: According to the actual requirements of the workpiece, fix one or more ceramic preforms in the casting cavity, control the gap between two adjacent ceramic preforms to 5mm, and control the gap between the ceramic preforms and the cavity wall to 20mm.

[0088] Step 32: Pour the molten high-alloy steel into the casting cavity, with the pouring temperature controlled at 1550-1580℃ and the pouring speed controlled at 7kg / s. After complete solidification and cooling, remove the resulting composite material.

[0089] Step 4, heat treatment

[0090] Step 41, multi-stage normalizing heat treatment: Place the composite material in a heating furnace and heat it to 1080°C at a heating rate of 50-70°C / h, hold it at that temperature for 1 hour, and then cool it to 50-80°C in the furnace to complete the first normalizing heat treatment; After the first normalizing heat treatment, heat the composite material to 1020°C in the furnace at a heating rate of 40°C / h, hold it at that temperature for 4 hours, and then remove it and cool it to room temperature by air cooling to complete the second normalizing heat treatment.

[0091] Step 42, tempering heat treatment; the composite material after normalizing heat treatment is placed in a heat treatment furnace and heated to 650°C at a heating rate of 40°C / h and held for 1h. Then, it is cooled to 200°C at a cooling rate of 20°C / h and held for 1.5h. After cooling to room temperature, the metal matrix ceramic composite material is obtained.

[0092] In this invention, during the tempering process in step 42, the initial temperature of the heat treatment furnace does not exceed 100°C before the composite material after normalizing heat treatment is placed into the heat treatment furnace.

[0093] Microstructural analysis was performed using a Zeiss MERLIN high-resolution field emission scanning electron microscope, and the final microstructure of the metal matrix ceramic composite material is shown in the figure. Figure 2 As shown in the figure, the present invention can effectively ensure the porosity between ceramic particles in the preform by screening and pre-treating ceramic particles, including particle size screening, control of the proportion of particle size range, and polishing, so as to achieve full penetration of molten metal and completely cover the ceramic particles; at the same time, polishing the sharp edges of ceramic particles avoids stress concentration and effectively prevents the risk of breakage and peeling.

[0094] The energy dispersive spectroscopy (EDS) results for the metal matrix, ceramic matrix, and transition layer between the metal and ceramic are as follows: Figure 3 , Figure 4 , Figure 5 As shown in the figure, this invention effectively achieves metallurgical bonding between ceramic particles and high-temperature molten metal by pre-treating the surface of ceramic particles with a mixture of Al2O3 and B4C powders via thermal spraying. After cooling, a transitional bonding layer is formed, which significantly improves the bonding force between the metal and ceramic particles. This solves the problem that the traditional metal matrix and ceramic particles are only mechanically bonded, and the particles are prone to peeling and failure during use. This invention further promotes the coating of ceramic particles by molten metal with molten metal by adding a powder composed of Al2O3, B4C and Fe3O to the ceramic preform, and also effectively promotes the formation of a bonding transitional layer between the molten metal and ceramic particles.

[0095] Example 2

[0096] This embodiment 2 provides a method for preparing a metal-based ceramic composite material, the specific steps of which are as follows:

[0097] Step 1: Screening and pretreatment of ceramic particles

[0098] Step 11: Screen the particle size of the ceramic particles mixed with 50% zirconium corundum and 50% silicon carbide. The particle size range after screening is 2.8 to 3.5 mm, of which the proportion of ceramic particles with a particle size of 3 to 3.2 mm is not less than 80%.

[0099] Step 12: Put the screened ceramic particles into a ball mill to grind the edges and corners of the ceramic particles. Set the speed of the ball mill to 80 revolutions per minute and the grinding time to 2 hours.

[0100] Step 13: Weigh out 100 parts by weight of the polished ceramic particles, 1 part by weight of 500-mesh Al2O3 powder, and 2 parts by weight of 500-mesh B4C powder. Mix the Al2O3 and B4C powders evenly and spray the powder mixture evenly onto the ceramic particles using a thermal spraying method.

[0101] Step 2: Fabrication of ceramic preforms

[0102] Step 21: Weigh out 100 parts by weight of the pretreated mixed ceramic particles; weigh out 4 parts by weight of sodium silicate and 4 parts by weight of water, and mix the sodium silicate and water evenly to make 8 parts by weight of binder; weigh out 1 part by weight of 700-mesh Al2O3 powder, 1 part by weight of 700-mesh B4C powder, and 4 parts by weight of 900-mesh Fe3O powder, and mix the Al2O3, B4C, and Fe3O powder evenly to make 6 parts by weight of mixed powder; then, mix the 100 parts by weight of the pretreated ceramic particles, 8 parts by weight of binder, and 6 parts by weight of mixed powder evenly, and fill the mold for making the preform, and perform a first curing treatment; the first curing treatment process is as follows: first, pass CO2 gas for 1 minute, remove the mold, put it in the drying room for 2 hours, and set the drying room temperature to 100℃; after the first curing treatment, a preliminary ceramic preform is obtained.

[0103] Step 22: Place the pre-formed ceramic preform into a device with heating and pressurizing functions for secondary curing. The secondary curing process is as follows: the device first heats up to 600℃ at 1℃ / min, then heats up to 1050℃ at 0.5℃ / min, holds for 30 minutes, then cools down to 870℃ at 1℃ / min and holds for 30 minutes. At the same time, the device applies a compressive stress of 150 kg to the ceramic preform, holds for 15 minutes, and then releases the pressure. After releasing the pressure, the device cools down to room temperature at 2℃ / min to complete the production of the ceramic preform.

[0104] Step 3: Casting and molding of metal-based ceramic composite materials

[0105] Step 31: According to the actual requirements of the workpiece, fix one or more ceramic preforms in the casting cavity, control the gap between two adjacent ceramic preforms to 10mm, and control the gap between the ceramic preforms and the cavity wall to 28mm.

[0106] Step 32: Pour the high-chromium cast iron liquid into the casting cavity, control the pouring temperature at 1500-1520℃, control the pouring speed at 10kg / s, and remove the resulting composite material after it has completely solidified and cooled.

[0107] Step 4, heat treatment

[0108] Step 41, multi-stage normalizing heat treatment: Place the composite material in a heating furnace and heat it to 1080°C at a heating rate of 50-70°C / h, hold it at that temperature for 1 hour, and then cool it to 50-80°C in the furnace to complete the first normalizing heat treatment; After the first normalizing heat treatment, heat the composite material to 1020°C in the furnace at a heating rate of 30°C / h, hold it at that temperature for 4 hours, and then remove it and cool it to room temperature by air cooling to complete the second normalizing heat treatment.

[0109] Step 42, tempering heat treatment; the composite material after normalizing heat treatment is placed in a heat treatment furnace and heated to 650°C at a heating rate of 30°C / h and held for 1h. Then, it is cooled to 200°C at a cooling rate of 15°C / h and held for 1.5h. After cooling to room temperature, the metal matrix ceramic composite material is obtained.

[0110] In this invention, during the tempering process in step 42, the initial temperature of the heat treatment furnace does not exceed 100°C before the normalized composite material is placed into the heat treatment furnace.

[0111] Example 3

[0112] This embodiment 3 provides a method for preparing a metal-based ceramic composite material, the specific steps of which are as follows:

[0113] Step 1: Screening and pretreatment of ceramic particles

[0114] Step 11: Screen the particle size of the mixed ceramic particles of 70% zirconium corundum, 20% silicon carbide and 10% titanium carbide. The particle size range after screening is 3.5 to 4 mm, of which the proportion of ceramic particles with a particle size of 3.5 to 3.7 mm is not less than 85%.

[0115] Step 12: Put the screened ceramic particles into a ball mill to grind the edges and corners of the ceramic particles. Set the speed of the ball mill to 120 revolutions per minute and the grinding time to 1 hour.

[0116] Step 13: Weigh out 100 parts by weight of the polished ceramic particles, 1 part by weight of 600-mesh Al2O3 powder, and 1.5 parts by weight of 600-mesh B4C powder. Mix the Al2O3 and B4C powder evenly and spray the powder mixture evenly onto the ceramic particles using a thermal spraying method.

[0117] Step 2: Fabrication of ceramic preforms

[0118] Step 21: Weigh out 100 parts by weight of the pretreated mixed ceramic particles; weigh out 4 parts by weight of sodium silicate and 2 parts by weight of water, and mix the sodium silicate and water evenly to make 6 parts by weight of binder; weigh out 1 part by weight of 750-mesh Al2O3 powder, 1 part by weight of 750-mesh B4C powder, and 6 parts by weight of 950-mesh Fe3O powder, and mix the Al2O3, B4C, and Fe3O powder evenly to make 8 parts by weight of mixed powder; then, mix the 100 parts by weight of the pretreated ceramic particles, 6 parts by weight of binder, and 8 parts by weight of mixed powder evenly, and fill the mold for making the preform, and perform a first curing treatment; the first curing treatment process is as follows: first, pass CO2 gas for 2 minutes, remove the mold, put it in the drying room for 3 hours, and set the drying room temperature to 80℃; after the first curing treatment, a preliminary ceramic preform is obtained.

[0119] Step 22: Place the pre-formed ceramic preform into a device with heating and pressurizing functions for secondary curing. The secondary curing process is as follows: the device first heats up to 600℃ at 1.5℃ / min, then heats up to 1120℃ at 0.6℃ / min, holds at that temperature for 30 minutes, then cools down to 875℃ at 1.5℃ / min and holds at that temperature. At the same time, the device applies a compressive stress of 150 kg to the ceramic preform, holds the pressure for 15 minutes, then releases the pressure. After releasing the pressure, the device cools down to room temperature at 2.5℃ / min, thus completing the production of the ceramic preform.

[0120] Step 3: Casting and molding of metal-based ceramic composite materials

[0121] Step 31: According to the actual requirements of the workpiece, fix one or more ceramic preforms in the casting cavity, control the gap between two adjacent ceramic preforms to 7mm, and control the gap between the ceramic preforms and the cavity wall to 25mm.

[0122] Step 32: Pour the molten high-manganese steel into the casting cavity, with the pouring temperature controlled at 1520-1550℃ and the pouring speed controlled at 8kg / s. After complete solidification and cooling, remove the resulting composite material.

[0123] Step 4, heat treatment

[0124] Step 41, multi-stage normalizing heat treatment: Place the composite material in a heating furnace and heat it to 1100°C at a heating rate of 50-70°C / h, hold it at that temperature for 1 hour, and then cool it to 50-80°C in the furnace to complete the first normalizing heat treatment; After the first normalizing heat treatment, heat the composite material to 700°C in the furnace at a heating rate of 50°C / h, and then heat it to 1020°C in the furnace at a heating rate of 30°C / h, hold it at that temperature for 4 hours, and then remove it and cool it to room temperature by oil cooling to complete the second normalizing heat treatment.

[0125] Step 42, tempering heat treatment; the composite material after normalizing heat treatment is placed in a heat treatment furnace and heated to 650°C at a heating rate of 50°C / h and held for 1h. Then, it is cooled to 200°C at a cooling rate of 30°C / h and held for 1.5h. After cooling to room temperature, the metal matrix ceramic composite material is obtained.

[0126] In this invention, during the tempering process in step 42, the initial temperature of the heat treatment furnace does not exceed 100°C before the normalized composite material is placed into the heat treatment furnace.

[0127] This invention effectively ensures the porosity between ceramic particles in the preform by screening the particle size and controlling the proportion of particle size range, allowing the molten metal to better penetrate into the preform and completely encapsulate the ceramic particles. This invention also removes the sharp edges of the ceramic particles by grinding them, avoiding the risk of stress concentration leading to particle breakage and peeling during subsequent use.

[0128] This invention, through thermal spraying of a mixture of Al2O3 and B4C powder onto the surface of ceramic particles, effectively achieves metallurgical bonding between ceramic particles and high-temperature molten metal via the mixed powder. After cooling, a transitional bonding layer is formed, significantly improving the bonding force between the metal and ceramic. This effectively solves the problem that traditional metal-based ceramic particles are only mechanically bonded, and the particles are prone to peeling and failure during use.

[0129] The ceramic preform of this invention undergoes two curing processes during its fabrication, which significantly enhances the strength of the preform itself, preventing it from collapsing or breaking during the pouring of molten metal. This effectively ensures that the ceramic particles are dispersed in their original positions, resulting in excellent wear resistance.

[0130] The addition of a powder composed of Al2O3, B4C and Fe3O to the ceramic preform of the present invention can actively help the molten metal to coat the ceramic particles, and can also effectively promote the formation of a metallurgical bonding transition layer between the molten metal and the ceramic particles.

[0131] The heat treatment in this invention can effectively eliminate the casting residual stress generated during the casting process of the composite material and eliminate the cracking problem of the composite layer.

[0132] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for producing a cermet composite material, characterized by, The specific steps are as follows: Step 1: Screening and pretreatment of ceramic particles Step 11: Screen the ceramic particles by size to make the particle size as uniform as possible; Step 12: Place the screened ceramic particles into a ball mill to grind the edges and corners of the ceramic particles; Step 13: After grinding, the ceramic particles are uniformly sprayed with a mixture of Al2O3 and B4C powders using a thermal spraying method. Step 2: Fabrication of ceramic preforms Step 21: After the pre-treated ceramic particles, binder and mixed powder are mixed evenly, they are filled into the mold for making the preform and cured once. After the first curing treatment, a preliminary ceramic preform is obtained. Step 22: Place the pre-formed ceramic preform into a device with heating and pressurizing functions for secondary curing to obtain the ceramic preform. The secondary curing process is as follows: The device first heats up at a rate of 0.5~2℃ / min to 1000~1150℃ and holds for 30min. Then the device begins to cool down at a rate of 1~2℃ / min until it reaches 850~880℃ and holds. At the same time, the device applies a compressive stress of 100~200 kg to the pre-formed ceramic preform and holds for 15min before releasing the pressure. After releasing the pressure, the device continues to cool down at a rate of 2~3℃ / min until it reaches room temperature. The ceramic preform is then removed from the device. Step 3: Casting and molding of metal-based ceramic composite materials Step 31: Fix one or more ceramic preforms in the casting cavity; Step 32: Pour the molten metal into the casting cavity, and after it has completely solidified and cooled, remove the resulting composite material. Step 4, heat treatment Step 41: Perform multi-stage normalizing heat treatment on the composite material. The steps of multi-stage normalizing heat treatment are as follows: place the composite material in a heating furnace, raise the temperature to 1080~1100℃ at a heating rate of 50~70℃ / h, hold for 1h, and then cool to 50~80℃ in the furnace to complete the first normalizing heat treatment; raise the temperature of the composite material after the first normalizing heat treatment to 980~1020℃ in the furnace, hold for 4h, remove and cool to room temperature to complete the second normalizing heat treatment; Step 42: Perform tempering heat treatment on the composite material after normalizing heat treatment to obtain metal matrix ceramic composite material. The steps of tempering heat treatment are as follows: place the composite material after normalizing heat treatment in a heat treatment furnace, raise the temperature to 650℃ at a heating rate not exceeding 50℃ / h, hold for 1h, then lower the temperature to 200℃ at a cooling rate not exceeding 30℃ / h, hold for 1.5h, remove and air cool to room temperature.

2. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 11, the ceramic particles are one or a mixture of several of the following in any proportion: zirconium corundum, alumina, silicon nitride, silicon carbide, boron carbide, titanium carbide, titanium boride, and tungsten carbide.

3. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 11, the particle size of the ceramic particles after screening ranges from 1 to 5 mm.

4. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 12, the ball mill rotates at a speed of 50-120 r / min, and the grinding time is 1-2 hours.

5. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 13, the powder mixture of Al2O3 and B4C has a mesh size of 500-600 mesh, the weight of the powder mixture accounts for 1-3% of the weight of the ceramic particles to be sprayed, and the weight ratio of Al2O3 to B4C in the powder mixture is 1:3-1:

1.

6. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 21, when the amount of pretreated ceramic particles is 100 parts by weight, the amount of binder is 4 to 10 parts by weight, and the amount of mixed powder is 2 to 10 parts by weight.

7. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 21, the adhesive is a mixture of sodium silicate and water, with a weight ratio of sodium silicate to water of 1:1 to 4:

1.

8. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 21, the mixed powder is composed of Al2O3, B4C and Fe3O powders. The mesh size of Al2O3 and B4C powders is 600-800 mesh, and the mesh size of Fe3O powder is 800-1000 mesh. The weight ratio of the sum of Al2O3 and B4C to Fe3O is 1:3 to 1:1, and the weight ratio of Al2O3 to B4C is 1:

1. The main components of Fe3O are 0.7-0.8% C, 12-14% Cr, 28-30% Ni, and the balance Fe.

9. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 21, the first curing process is as follows: first, CO2 gas is passed through for 1 to 2 minutes, then the mold is removed and placed in a drying room for 2 to 4 hours at a temperature of 50 to 100°C.

10. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 31, when one or more ceramic preforms are fixedly placed in the casting cavity, the gap between two adjacent ceramic preforms is controlled at 5-10 mm, and the gap between the ceramic preform and the cavity wall is controlled at 20-30 mm.

11. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 32, the molten metal is high-alloy steel, high-manganese steel, or high-chromium cast iron.

12. The method for preparing the metal-based ceramic composite material according to claim 1, characterized in that, In step 32, the pouring temperature is controlled at 1500~1580℃ and the pouring speed is controlled at 6~10kg / s.

13. A metal-based ceramic composite material, characterized in that, The metal-based ceramic composite material was prepared using the preparation method according to any one of claims 1-12.

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