Sintering bearing plate for sintering powder metallurgy product and preparation method of sintering bearing plate

Abstract

The invention provides a setter plate for sintering a powder metallurgy product and a preparation method of the setter plate, and belongs to the technical field of setter plates. The refractory material is prepared from the following raw materials in parts by weight: 20-40 parts of fused zirconium mullite, 20-40 parts of modified sintered corundum, 30-50 parts of alumina micro powder, 0.5-1 part of yttrium oxide / alumina-carbon nanotube hollow microsphere powder, 0.5-1 part of zinc oxide micro powder and 5-10 parts of a binder. The setter plate for sintering the powder metallurgy product has the advantages of good heat insulation, high temperature resistance, thermal shock resistance and chemical stability, good mechanical properties, good hardness and good wear resistance, the problems of cracking, deformation and the like caused by thermal shock are reduced, the service life of the setter plate is prolonged, and the setter plate has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of setter plates, and in particular to a setter plate for sintering powder metallurgy products and a preparation method thereof. Background Art

[0002] Metal Injection Molding (MIM) has become a rapidly developing and most promising new near-net-shape forming technology in the field of powder metallurgy, hailed as one of the "hottest metal component forming technologies internationally." MIM is a method of injection molding a mixture of metal powder and a binder. The selected powder and binder are first mixed, the mixture is granulated, and then injection molded into the desired shape. The binder is removed through degreasing and sintering, resulting in the desired metal product.

[0003] Currently, there are two main types of MIM sintering furnaces on the market: vacuum furnaces and continuous furnaces. Compared to intermittent vacuum furnaces, continuous furnaces offer the advantages of higher production efficiency, lower production costs, simpler operation, and more consistent sintering quality. To enable the production of high-density stainless steel parts even with ammonia decomposition gas as a protective atmosphere, a rapid cooling device is installed at the rear end of the continuous furnace. 99% alumina ceramic plates have poor thermal shock resistance and are prone to fracture. Currently, corundum-mullite setter plates are primarily used, offering better thermal shock resistance. However, the larger particle size used in the feed results in a rough surface that can easily scratch metal parts. Furthermore, the mullite binder phase is susceptible to reductive decomposition under the action of ammonia decomposition gas (N2 / H2), generating gaseous SiO that escapes, resulting in a loose structure, sanding, and product contamination.

[0004] Therefore, it is necessary to develop a setter with stable high temperature performance, good thermal shock resistance and smooth surface. Summary of the Invention

[0005] The purpose of the present invention is to provide a setter for sintering powder metallurgy products and a preparation method thereof, which has good anti-aging effect.

[0006] The technical solution of the present invention is achieved as follows: The invention provides a setter for sintering powder metallurgy products. The setter is prepared from the following raw materials in parts by weight: 20-40 parts of fused zirconium mullite, 20-40 parts of modified sintered corundum, 30-50 parts of alumina micropowder, 0.5-1 part of yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder, 0.5-1 part of zinc oxide micropowder, and 5-10 parts of a binder.

[0007] As a further improvement of the present invention, the preparation method of the yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder is as follows: S1. The formaldehyde solution and water were mixed, melamine was added, the pH value of the solution was adjusted, the reaction was stirred, a metal salt was added, the reaction was continued with stirring, centrifuged, washed, and dried to obtain metal ion-loaded melamine-formaldehyde microspheres; S2. Yttrium nitrate and urea were added to water, followed by metal ion-loaded melamine-formaldehyde microspheres and aluminum isopropoxide. The mixture was ultrasonically treated, heated in a water bath with stirring, and reacted. The mixture was centrifuged, washed, dried, and calcined to produce yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder.

[0008] As a further improvement of the present invention, the mass ratio of the formaldehyde solution, water, melamine and metal salt in step S1 is 9-10:180-220:2-3:0.1-0.2, the metal salt is nickel chloride or cobalt chloride, the pH value of the solution is adjusted to 5-5.5, and the stirring reaction is for 20-30 minutes.

[0009] As a further improvement of the present invention, the mass ratio of yttrium nitrate, urea, metal ion-loaded melamine-formaldehyde microspheres and aluminum isopropoxide in step S2 is 2-3:20-30:1.5-2.5:2-4, the power of the ultrasonic treatment is 500-1000 W, the time is 20-30 min, the temperature of the water bath heating and stirring reaction is 80-90 ° C, the time is 2-4 h, and the calcination temperature is 850-950 ° C, and the time is 1-2 h.

[0010] As a further improvement of the present invention, the preparation method of the modified sintered corundum is as follows: T1. Ball milling the sintered corundum to obtain sintered corundum powder; T2. The sintered corundum powder was added to a Tris-HCl solution, dopamine hydrochloride was added, the reaction was heated with stirring, centrifuged, washed, and dried to obtain a modified sintered corundum powder; T3. The modified sintered corundum powder was added to water, formaldehyde, melamine was added, heated and stirred to mix, citric acid and polyvinyl alcohol were added, the reaction was stirred and kept warm, filtered, washed, and dried to obtain a sintered corundum powder loaded with an organic resin; T4. The sintered corundum powder loaded with an organic resin was washed sequentially with acetone, alcohol, and deionized water, dried, moved into a vacuum chamber, introduced with hydrogen, and subjected to hydrogen plasma treatment. Tetramethylsilane and trans-dibutylene were introduced, coated, and then subjected to hydrogen plasma treatment to obtain a sintered corundum powder loaded with a silicon coating / organic resin. T5. The loaded silicon coating / organic resin sintered corundum powder is added to water, zinc salt is added, stirred and mixed, sodium tungstate is added, hydrothermal reaction is performed, filtered, washed, and dried to obtain loaded sintered corundum powder; T6. Heat and calcine the loaded sintered corundum powder under inert gas protection to obtain modified sintered corundum.

[0011] As a further improvement of the present invention, the ball milling time in step T1 is 1-2 hours; the pH value of the Tris-HCl solution in step T2 is 8.5-9.5, the mass ratio of the sintered corundum powder to dopamine hydrochloride is 10:3-4, and the heating and stirring reaction temperature is 45-55°C and the time is 3-5 hours.

[0012] As a further improvement of the present invention, the mass ratio of the modified sintered corundum powder, formaldehyde, melamine, citric acid and polyvinyl alcohol in step T3 is 10:2-3:2-3:0.1-0.3:0.4-0.6, the heating temperature is 75-85°C, and the insulation stirring reaction time is 5-15 minutes; the hydrogen ventilation rate in step T4 is 8-10sccm, the tetramethylsilane ventilation rate is 0.15-0.4sccm, the trans-dibutene ventilation rate is 0.3-0.5sccm, and the coating treatment time is 50-60 minutes.

[0013] As a further improvement of the present invention, the mass ratio of the sintered corundum powder loaded with silicon coating / organic resin and the zinc salt in step T5 is 10:2-3, the amounts of the zinc salt and sodium tungstate are equal, the zinc salt is selected from at least one of zinc chloride, zinc sulfate, and zinc nitrate, the temperature of the hydrothermal reaction is 170-190° C., and the time is 4-6 hours; the temperature of the heating and calcining in step T6 is 1600-1800° C., and the time is 1-3 hours.

[0014] As a further improvement of the present invention, the binder is polyvinyl alcohol.

[0015] The present invention further protects a method for preparing the above-mentioned setter for sintering powder metallurgy products, comprising the following steps: (1) Treatment of the binder: Prepare the binder into a 10-15 wt% aqueous solution; (2) Making granules: Weigh various raw materials in proportion and put them into a ball mill, add a binder solution, and mill to obtain a mixed slurry. The ball milling medium is high-purity alumina balls, and spray drying is used to make granules. (3) Pressing: Weigh a certain amount of the granulated material prepared in step (2) and pour it into a mold, and press it into a green body at a pressure of 120-160 MPa; (4) Drying and sintering: After the green body is naturally dried for 12-16 hours, it is transferred to an electric heating drying oven for drying at 120-150℃ for 6-12 hours to fully evaporate the moisture therein. Then it is placed in a high-temperature electric furnace and kept at 1600-1700℃ for 6-10 hours. After natural cooling, the sintering plate for powder metallurgy products is obtained.

[0016] The present invention has the following beneficial effects: 1. Fused zirconium mullite and sintered corundum have high thermal shock resistance and chemical stability; The present invention obtains highly uniform powder by ball milling sintered corundum, and after the surface is modified with polydopamine, it can adsorb melamine and formaldehyde, so that melamine-formaldehyde resin can be deposited on the surface of the modified sintered corundum, thereby preparing sintered corundum powder loaded with organic resin, and then chemical vapor deposition of silicon-doped hydrocarbon polymer coating is continued on the surface, and then zinc ions are adsorbed on the surface, and hydrothermally reacted with sodium tungstate in situ. After high-temperature calcination, the melamine-formaldehyde resin is pyrolyzed and vaporized into CO and NH3, which serve as reducing gas and carbon source, and can promote the decomposition of tungsten. Zinc oxide is reduced to form WC, and Zn ions are reduced to form Zn single-atom metal. As a catalyst, CO is used as a carbon source to self-catalyze in-situ deposition to form carbon nanotubes. At the same time, high temperature will also cause the hydrocarbon polymer coating to react to form a SiC layer, so that the surface of the sintered corundum is loaded with a layer of SiC-WC-carbon nanotubes. The fracture toughness is improved through interface bridging and crack deflection, while the thermal conductivity is enhanced, the temperature gradient and thermal stress of the setter are reduced, and a dense anti-oxidation layer is formed to block the contact between O2 and the pusher substrate, while improving the surface hardness and wear resistance. 2. The particle size of the raw materials in the batch is below 325 mesh. After spray granulation, the surface of the prepared setter is fine and smooth; 3. Alumina is used as the binding phase without the introduction of silicon oxide, which avoids reduction porosity and improves the material's high temperature resistance and thermal shock resistance. Its hardness makes the surface of the setter more wear-resistant, effectively resisting the wear of the powder metallurgy products on the surface of the setter during the placement and sintering process, thereby extending the service life of the setter. 4. Add yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder and zinc oxide powder, react with alumina powder at high temperature to form a solid solution reaction, promote sintering, and improve the high-temperature creep performance and mechanical strength of the support plate. In addition, yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder is based on melamine-formaldehyde resin and loaded with metal salts, with aluminum oxide and yttrium oxide deposited on the surface. After high-temperature calcination, melamine-formaldehyde resin is pyrolyzed and vaporized into CO and NH3, which, as reducing gas and carbon source, can promote the reduction of zinc tungstate to form WC, and reduce Zn ions to form Zn single atomic metal, which acts as a catalyst and CO as a carbon source, and self-catalyzes in-situ deposition to form carbon nanotubes, thereby producing yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder, which has The hollow structure will reflect and scatter heat on the inner surface of the microspheres during the transfer process, thereby reducing heat conduction and significantly improving the thermal insulation performance of the setter plate, which helps to reduce heat loss during the sintering process. At the same time, the thermal expansion coefficient is low, and its volume changes less when the temperature changes, which can alleviate the thermal stress caused by sudden temperature changes and improve the thermal shock resistance of the setter plate, so that it can better adapt to rapid temperature changes during the sintering process, reduce cracking, deformation and other problems caused by thermal shock, and extend the service life of the setter plate.

[0017] The setter plate for sintering powder metallurgy products prepared by the present invention has good heat insulation, high temperature resistance, thermal shock resistance and chemical stability, good mechanical properties, good hardness and wear resistance, reduces problems such as cracking and deformation caused by thermal shock, extends the service life of the setter plate, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a microstructure diagram of the setter for sintering powder metallurgy products prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0020] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] Preparation Example 1 Preparation of Yttrium Oxide / Aluminum Oxide-Carbon Nanotube Hollow Microsphere Powder

[0022] Here’s how: S1. 9 g of formaldehyde solution and 180 mL of water were mixed, 2 g of melamine was added, the pH of the solution was adjusted to 5, and the reaction was stirred for 20 min. 0.1 g of nickel chloride was added, and the reaction was continued with stirring for 10 min. The mixture was centrifuged, washed, and dried to obtain metal ion-loaded melamine-formaldehyde microspheres. S2. 2 g of yttrium nitrate and 20 g of urea were added to 300 mL of water. 1.5 g of metal ion-loaded melamine-formaldehyde microspheres and 2 g of aluminum isopropoxide were also added. The mixture was ultrasonically treated at 500 W for 20 min. The mixture was heated to 80°C in a water bath and stirred for 2 h. The mixture was centrifuged, washed, dried, and calcined at 850°C under nitrogen for 1 h to produce yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder.

[0023] Preparation Example 2 Preparation of Yttrium Oxide / Aluminum Oxide-Carbon Nanotube Hollow Microsphere Powder

[0024] Here’s how: S1. 10 g of formaldehyde solution and 220 mL of water were mixed, 3 g of melamine was added, the pH of the solution was adjusted to 5.5, and the reaction was stirred for 30 min. 0.2 g of cobalt chloride was added, and the reaction was continued with stirring for 20 min. The mixture was centrifuged, washed, and dried to obtain metal ion-loaded melamine-formaldehyde microspheres. S2. 3 g of yttrium nitrate and 30 g of urea were added to 300 mL of water. 2.5 g of metal ion-loaded melamine-formaldehyde microspheres and 4 g of aluminum isopropoxide were also added. The mixture was ultrasonically treated at 1000 W for 30 min. The mixture was heated to 90°C in a water bath and stirred for 4 h. The mixture was centrifuged, washed, dried, and calcined at 950°C under nitrogen for 2 h to produce yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder.

[0025] Preparation Example 3 Preparation of Yttrium Oxide / Aluminum Oxide-Carbon Nanotube Hollow Microsphere Powder

[0026] Here’s how: S1. 9.5 g of formaldehyde solution and 200 mL of water were mixed, 2.5 g of melamine was added, the pH of the solution was adjusted to 5.2, and the reaction was stirred for 25 min. 0.15 g of nickel chloride was added, and the reaction was continued with stirring for 15 min. The mixture was centrifuged, washed, and dried to obtain metal ion-loaded melamine-formaldehyde microspheres. S2. 2.5 g of yttrium nitrate and 25 g of urea were added to 300 mL of water. 2 g of metal ion-loaded melamine-formaldehyde microspheres and 3 g of aluminum isopropoxide were also added. The mixture was ultrasonically treated at 700 W for 25 min. The mixture was heated to 85°C in a water bath and stirred for 3 h. The mixture was centrifuged, washed, dried, and calcined at 900°C under nitrogen for 1.5 h to produce yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder.

[0027] Comparative Preparation Example 1

[0028] Compared with Preparation Example 3, the difference is that aluminum isopropoxide is not added in step S2.

[0029] The details are as follows: S1. 9.5 g of formaldehyde solution and 200 mL of water were mixed, 2.5 g of melamine was added, the pH of the solution was adjusted to 5.2, and the reaction was stirred for 25 min. 0.15 g of nickel chloride was added, and the reaction was continued with stirring for 15 min. The mixture was centrifuged, washed, and dried to obtain metal ion-loaded melamine-formaldehyde microspheres. S2. 2.5 g of yttrium nitrate and 25 g of urea were added to 300 mL of water, along with 2 g of metal ion-loaded melamine-formaldehyde microspheres. The mixture was ultrasonically treated at 700 W for 25 min, heated to 85°C in a water bath, and stirred for 3 h. The mixture was centrifuged, washed, and dried. Yttrium oxide-carbon nanotube hollow microsphere powder was obtained by calcining at 900°C for 1.5 h under nitrogen.

[0030] Comparative Preparation Example 2

[0031] Compared with Preparation Example 3, the difference is that step S1 is not performed.

[0032] The details are as follows:

[0033] 2.5 g of yttrium nitrate and 25 g of urea were added to 300 mL of water, and 3 g of aluminum isopropoxide was added. The mixture was ultrasonically treated at 700 W for 25 min, heated to 85 ° C in a water bath, stirred for 3 h, centrifuged, washed, dried, and calcined at 900 ° C for 1.5 h under nitrogen protection to obtain yttrium oxide / alumina microsphere powder.

[0034] Preparation Example 4 Preparation of modified sintered corundum

[0035] Here’s how: T1. The sintered corundum was ball-milled for 1 hour to obtain sintered corundum powder; T2. Add 10 g of sintered corundum powder to 200 mL of Tris-HCl solution (pH 8.5), add 3 g of dopamine hydrochloride, heat to 45°C, stir for 3 h, centrifuge, wash, and dry to obtain modified sintered corundum powder. T3. Add 10g of modified sintered corundum powder to 200mL of water, along with 2g of formaldehyde and 2g of melamine. Heat to 75°C and stir to mix thoroughly. Then add 0.1g of citric acid and 0.4g of polyvinyl alcohol. Keep stirring for 5 minutes. Filter, wash, and dry to obtain sintered corundum powder loaded with organic resin. T4. The organic resin-loaded sintered corundum powder was sequentially washed with acetone, alcohol, and deionized water, dried, and placed in a vacuum chamber. Hydrogen gas was introduced at a flow rate of 8 sccm and subjected to a hydrogen plasma treatment for 0.5 h. Tetramethylsilane and trans-dibutylene were then introduced at a flow rate of 0.15 sccm for tetramethylsilane and 0.3 sccm for trans-dibutylene. The powder was coated for 50 min and then subjected to a further hydrogen plasma treatment for 2 h to obtain a sintered corundum powder loaded with a silicon coating / organic resin. T5. Add 10g of silicon-coated / organic resin-loaded sintered corundum powder to 200mL of water, add 2g of zinc sulfate, and stir to mix thoroughly. Then, add sodium tungstate in an amount equal to the zinc sulfate. Hydrothermally react at 170°C for 4h. Filter, wash, and dry to obtain the loaded sintered corundum powder. T6. Heat the loaded sintered corundum powder to 1600℃ under nitrogen protection and calcine for 1 hour to obtain modified sintered corundum.

[0036] Preparation Example 5 Preparation of modified sintered corundum

[0037] Here’s how: T1. The sintered corundum was ball-milled for 2 hours to obtain sintered corundum powder; T2. Add 10 g of sintered corundum powder to 200 mL of Tris-HCl solution (pH 9.5), add 4 g of dopamine hydrochloride, heat to 55°C, stir for 5 h, centrifuge, wash, and dry to obtain modified sintered corundum powder. T3. Add 10g of modified sintered corundum powder to 200mL of water, along with 3g of formaldehyde and 3g of melamine. Heat to 85°C and stir to mix thoroughly. Then add 0.3g of citric acid and 0.6g of polyvinyl alcohol. Keep stirring for 15 minutes. Filter, wash, and dry to obtain sintered corundum powder loaded with organic resin. T4. The organic resin-loaded sintered corundum powder was sequentially washed with acetone, alcohol, and deionized water, dried, and placed in a vacuum chamber. Hydrogen gas was introduced at a flow rate of 10 sccm and subjected to a hydrogen plasma treatment for 0.5 h. Tetramethylsilane and trans-dibutylene were introduced at a flow rate of 0.4 sccm for tetramethylsilane and 0.5 sccm for trans-dibutylene, respectively. The coating process lasted for 60 min, followed by a further hydrogen plasma treatment for 2 h to obtain a sintered corundum powder loaded with a silicon coating / organic resin. T5. Add 10g of silicon-coated / organic resin-loaded sintered corundum powder to 200mL of water, add 3g of zinc nitrate, and stir to mix thoroughly. Then, add sodium tungstate in an amount equal to the zinc nitrate. Hydrothermally react at 190°C for 6h. Filter, wash, and dry to obtain the loaded sintered corundum powder. T6. Heat the loaded sintered corundum powder to 1800℃ under nitrogen protection and calcine for 3 hours to obtain modified sintered corundum.

[0038] Preparation Example 6 Preparation of modified sintered corundum

[0039] Here’s how: T1. The sintered corundum was ball-milled for 1.5 hours to obtain sintered corundum powder; T2. Add 10 g of sintered corundum powder to 200 mL of Tris-HCl solution (pH 9), add 3.5 g of dopamine hydrochloride, heat to 50°C, stir and react for 4 hours, centrifuge, wash, and dry to obtain modified sintered corundum powder. T3. Add 10g of modified sintered corundum powder to 200mL of water, along with 2.5g of formaldehyde and 2.5g of melamine. Heat to 80°C and stir to mix thoroughly. Then add 0.2g of citric acid and 0.5g of polyvinyl alcohol. Keep stirring for 10 minutes. Filter, wash, and dry to obtain sintered corundum powder loaded with an organic resin. T4. The organic resin-loaded sintered corundum powder was sequentially washed with acetone, alcohol, and deionized water, dried, and placed in a vacuum chamber. Hydrogen gas was introduced at a flow rate of 9 sccm and subjected to a hydrogen plasma treatment for 0.5 h. Tetramethylsilane and trans-dibutylene were then introduced at a flow rate of 0.3 sccm for tetramethylsilane and 0.4 sccm for trans-dibutylene, respectively. The coating process lasted for 55 min, followed by a further hydrogen plasma treatment for 2 h to produce a sintered corundum powder loaded with a silicon coating / organic resin. T5. Add 10g of silicon-coated / organic resin-loaded sintered corundum powder to 200mL of water, add 2.5g of zinc chloride, and stir to mix thoroughly. Then add sodium tungstate in an amount equal to the zinc chloride. Hydrothermally react at 180°C for 5h. Filter, wash, and dry to obtain the loaded sintered corundum powder. T6. Heat the loaded sintered corundum powder to 1700℃ under nitrogen protection and calcine for 2 hours to obtain modified sintered corundum.

[0040] Comparative Preparation Example 3

[0041] Compared with Preparation Example 3, the difference is that step T3 is not performed.

[0042] The details are as follows: T1. The sintered corundum was ball-milled for 1.5 hours to obtain sintered corundum powder; T2. Add 10 g of sintered corundum powder to 200 mL of Tris-HCl solution (pH 9), add 3.5 g of dopamine hydrochloride, heat to 50°C, stir and react for 4 hours, centrifuge, wash, and dry to obtain modified sintered corundum powder. T3. The modified sintered corundum powder was sequentially washed with acetone, alcohol, and deionized water, dried, and placed in a vacuum chamber. Hydrogen gas was introduced at a flow rate of 9 sccm and subjected to a hydrogen plasma treatment for 0.5 h. Tetramethylsilane and trans-dibutylene were introduced at a flow rate of 0.3 sccm and 0.4 sccm, respectively. The powder was coated for 55 min and then subjected to a further hydrogen plasma treatment for 2 h to obtain silicon-coated sintered corundum powder. T4. Add 10g of silicon-coated sintered corundum powder to 200mL of water, add 2.5g of zinc chloride, and stir to mix thoroughly. Then add sodium tungstate in an amount equal to the zinc chloride. Hydrothermal reaction is carried out at 180°C for 5h. Filter, wash, and dry to obtain the loaded sintered corundum powder. T5. Heat the loaded sintered corundum powder to 1700℃ under nitrogen protection and calcine for 2 hours to obtain modified sintered corundum.

[0043] Comparative Preparation Example 4

[0044] Compared with Preparation Example 3, the difference is that step T4 is not performed.

[0045] The details are as follows: T1. The sintered corundum was ball-milled for 1.5 hours to obtain sintered corundum powder; T2. Add 10 g of sintered corundum powder to 200 mL of Tris-HCl solution (pH 9), add 3.5 g of dopamine hydrochloride, heat to 50°C, stir and react for 4 hours, centrifuge, wash, and dry to obtain modified sintered corundum powder. T3. Add 10g of modified sintered corundum powder to 200mL of water, along with 2.5g of formaldehyde and 2.5g of melamine. Heat to 80°C and stir to mix thoroughly. Then add 0.2g of citric acid and 0.5g of polyvinyl alcohol. Keep stirring for 10 minutes. Filter, wash, and dry to obtain sintered corundum powder loaded with an organic resin. T4. Add 10g of organic resin-loaded sintered corundum powder to 200mL of water, add 2.5g of zinc chloride, and stir to mix thoroughly. Then add sodium tungstate in an amount equal to the zinc chloride. Hydrothermal reaction is carried out at 180°C for 5h. Filter, wash, and dry to obtain the loaded sintered corundum powder. T5. Heat the loaded sintered corundum powder to 1700℃ under nitrogen protection and calcine for 2 hours to obtain modified sintered corundum.

[0046] Comparative Preparation Example 5

[0047] Compared with Preparation Example 3, the difference is that step T5 is not performed.

[0048] The details are as follows: T1. The sintered corundum was ball-milled for 1.5 hours to obtain sintered corundum powder; T2. Add 10 g of sintered corundum powder to 200 mL of Tris-HCl solution (pH 9), add 3.5 g of dopamine hydrochloride, heat to 50°C, stir and react for 4 hours, centrifuge, wash, and dry to obtain modified sintered corundum powder. T3. Add 10g of modified sintered corundum powder to 200mL of water, along with 2.5g of formaldehyde and 2.5g of melamine. Heat to 80°C and stir to mix thoroughly. Then add 0.2g of citric acid and 0.5g of polyvinyl alcohol. Keep stirring for 10 minutes. Filter, wash, and dry to obtain sintered corundum powder loaded with an organic resin. T4. The organic resin-loaded sintered corundum powder was sequentially washed with acetone, alcohol, and deionized water, dried, and placed in a vacuum chamber. Hydrogen gas was introduced at a flow rate of 9 sccm and subjected to a hydrogen plasma treatment for 0.5 h. Tetramethylsilane and trans-dibutylene were then introduced at a flow rate of 0.3 sccm for tetramethylsilane and 0.4 sccm for trans-dibutylene, respectively. The coating process lasted for 55 min, followed by a further hydrogen plasma treatment for 2 h to produce a sintered corundum powder loaded with a silicon coating / organic resin. T5. Heat the silicon-plated / organic resin-loaded sintered corundum powder to 1700°C under nitrogen and calcine for 2 hours to obtain modified sintered corundum.

[0049] Example 1

[0050] This embodiment provides a setter for sintering powder metallurgy products.

[0051] Raw material composition (parts by weight): 20 parts of fused zirconium mullite, 20 parts of modified sintered corundum obtained in Preparation Example 4, 30 parts of alumina powder, 0.5 parts of yttrium oxide / alumina-carbon nanotube hollow microsphere powder obtained in Preparation Example 1, 0.5 parts of zinc oxide powder, and 5 parts of polyvinyl alcohol.

[0052] The preparation method comprises the following steps: (1) Treatment of binder: prepare polyvinyl alcohol into a 10 wt% aqueous solution; (2) Making granules: Various raw materials weighed in proportion are placed in a ball mill, polyvinyl alcohol solution is added, and the mixed slurry is obtained by ball milling. The ball milling medium is high-purity alumina balls, and the granules are spray-dried; (3) Pressing: Pour the granulated material prepared in step (2) into a mold and press it into a green body at a pressure of 12 MPa; (4) Drying and sintering: After the green body is naturally dried for 12-16 hours, it is transferred to an electric heating drying oven and dried at 120℃ for 6 hours to fully evaporate the moisture in it. Then it is placed in a high-temperature electric furnace and kept at 1600℃ for 6 hours. After natural cooling, the sintering plate for powder metallurgy products is obtained. Figure 1 This is a micrograph of the setter used for sintering the powder metallurgy product, showing that the components are tightly bonded.

[0053] Example 2

[0054] This embodiment provides a setter for sintering powder metallurgy products.

[0055] Raw material composition (parts by weight): 40 parts of fused zirconium mullite, 40 parts of modified sintered corundum obtained in Preparation Example 5, 50 parts of alumina powder, 1 part of yttrium oxide / alumina-carbon nanotube hollow microsphere powder obtained in Preparation Example 2, 1 part of zinc oxide powder, and 10 parts of polyvinyl alcohol.

[0056] The preparation method comprises the following steps: (1) Treatment of binder: prepare polyvinyl alcohol into a 15 wt% aqueous solution; (2) Making granules: Various raw materials weighed in proportion are placed in a ball mill, polyvinyl alcohol solution is added, and the mixed slurry is obtained by ball milling. The ball milling medium is high-purity alumina balls, and the granules are spray-dried; (3) Pressing: Pour the granulated material prepared in step (2) into a mold and press it into a green body at a pressure of 160 MPa; (4) Drying and sintering: After the green body is naturally dried for 16 hours, it is transferred to an electric heating drying oven and dried at 150℃ for 12 hours to fully evaporate the moisture in it. Then it is placed in a high-temperature electric furnace and kept at 1700℃ for 10 hours. After natural cooling, the sintering plate for powder metallurgy products is obtained.

[0057] Example 3

[0058] This embodiment provides a setter for sintering powder metallurgy products.

[0059] Raw material composition (parts by weight): 30 parts of fused zirconium mullite, 30 parts of modified sintered corundum obtained in Preparation Example 6, 40 parts of alumina powder, 0.7 parts of yttrium oxide / alumina-carbon nanotube hollow microsphere powder obtained in Preparation Example 3, 0.7 parts of zinc oxide powder, and 7 parts of polyvinyl alcohol.

[0060] The preparation method comprises the following steps: (1) Treatment of binder: prepare polyvinyl alcohol into a 12 wt% aqueous solution; (2) Making granules: Various raw materials weighed in proportion are placed in a ball mill, polyvinyl alcohol solution is added, and the mixed slurry is obtained by ball milling. The ball milling medium is high-purity alumina balls, and the granules are spray-dried; (3) Pressing: Pour the granulated material prepared in step (2) into a mold and press it into a green body at a pressure of 140 MPa; (4) Drying and sintering: After the green body is naturally dried for 12-16 hours, it is transferred to an electric heating drying oven and dried at 135℃ for 9 hours to fully evaporate the moisture therein. Then it is placed in a high-temperature electric furnace and kept at 1650℃ for 8 hours. After natural cooling, the sintering plate for powder metallurgy products is obtained.

[0061] Comparative Example 1

[0062] Compared with Example 3, the difference is that the yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder is replaced by the product prepared in Comparative Preparation Example 1.

[0063] Comparative Example 2

[0064] Compared with Example 3, the difference is that the yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder is replaced by the product prepared in Comparative Preparation Example 2.

[0065] Comparative Example 3

[0066] Compared with Example 3, the difference is that the modified sintered corundum is prepared by Comparative Preparation Example 3.

[0067] Comparative Example 4

[0068] Compared with Example 3, the difference is that the modified sintered corundum is prepared by Comparative Preparation Example 4.

[0069] Comparative Example 5

[0070] Compared with Example 3, the difference is that the modified sintered corundum is prepared by Comparative Preparation Example 5.

[0071] Test Example 1

[0072] The performance of the setters for sintering the powder metallurgy products prepared in Examples 1-3 and Comparative Examples 1-5 was tested. The results are shown in Table 1.

[0073] Table 1

[0074] It can be seen from the above table that the setters for sintering powder metallurgy products prepared in Examples 1-3 of the present invention have good comprehensive properties.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A setter for sintering powder metallurgy products, characterized in that: The invention is prepared from the following raw materials in parts by weight: 20-40 parts of fused zirconium mullite, 20-40 parts of modified sintered corundum, 30-50 parts of alumina micropowder, 0.5-1 part of yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder, 0.5-1 part of zinc oxide micropowder and 5-10 parts of binder.

2. The setter for sintering powder metallurgy products according to claim 1, characterized in that: The preparation method of the yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder is as follows: S1. The formaldehyde solution and water were mixed, melamine was added, the pH value of the solution was adjusted, the reaction was stirred, a metal salt was added, the reaction was continued with stirring, centrifuged, washed, and dried to obtain metal ion-loaded melamine-formaldehyde microspheres; S2. Yttrium nitrate and urea were added to water, followed by metal ion-loaded melamine-formaldehyde microspheres and aluminum isopropoxide. The mixture was ultrasonically treated, heated in a water bath with stirring, and reacted. The mixture was centrifuged, washed, dried, and calcined to produce yttrium oxide / aluminum oxide-carbon nanotube hollow microsphere powder.

3. The setter for sintering powder metallurgy products according to claim 2, characterized in that: In step S1, the mass ratio of the formaldehyde solution, water, melamine, and metal salt is 9-10:180-220:2-3:0.1-0.2, the metal salt is nickel chloride or cobalt chloride, the pH value of the solution is adjusted to 5-5.5, and the stirring reaction is carried out for 20-30 minutes.

4. The setter for sintering powder metallurgy products according to claim 2, characterized in that: The mass ratio of yttrium nitrate, urea, metal ion-loaded melamine-formaldehyde microspheres and aluminum isopropoxide in step S2 is 2-3:20-30:1.5-2.5:2-4, the power of the ultrasonic treatment is 500-1000W, the time is 20-30min, the temperature of the water bath heating and stirring reaction is 80-90°C, the time is 2-4h, and the calcination temperature is 850-950°C, and the time is 1-2h.

5. The setter for sintering powder metallurgy products according to claim 1, characterized in that: The preparation method of the modified sintered corundum is as follows: T1. Ball milling the sintered corundum to obtain sintered corundum powder; T2. The sintered corundum powder was added to a Tris-HCl solution, dopamine hydrochloride was added, the reaction was heated with stirring, centrifuged, washed, and dried to obtain a modified sintered corundum powder; T3. The modified sintered corundum powder was added to water, formaldehyde, melamine was added, heated and stirred to mix, citric acid and polyvinyl alcohol were added, the reaction was stirred and kept warm, filtered, washed, and dried to obtain a sintered corundum powder loaded with an organic resin; T4. The sintered corundum powder loaded with an organic resin was washed sequentially with acetone, alcohol, and deionized water, dried, moved into a vacuum chamber, introduced with hydrogen, and subjected to hydrogen plasma treatment. Tetramethylsilane and trans-dibutylene were introduced, coated, and then subjected to hydrogen plasma treatment to obtain a sintered corundum powder loaded with a silicon coating / organic resin. T5. The loaded silicon coating / organic resin sintered corundum powder is added to water, zinc salt is added, stirred and mixed, sodium tungstate is added, hydrothermal reaction is performed, filtered, washed, and dried to obtain loaded sintered corundum powder; T6. Heat and calcine the loaded sintered corundum powder under inert gas protection to obtain modified sintered corundum.

6. The setter for sintering powder metallurgy products according to claim 5, characterized in that: The ball milling time in step T1 is 1-2 hours; the pH value of the Tris-HCl solution in step T2 is 8.5-9.5, the mass ratio of the sintered corundum powder and dopamine hydrochloride is 10:3-4, and the heating and stirring reaction temperature is 45-55°C and the time is 3-5 hours.

7. The setter for sintering powder metallurgy products according to claim 5, characterized in that: In step T3, the mass ratio of the modified sintered corundum powder, formaldehyde, melamine, citric acid and polyvinyl alcohol is 10:2-3:2-3:0.1-0.3:0.4-0.6, the heating temperature is 75-85°C, and the insulation stirring reaction time is 5-15 minutes; in step T4, the hydrogen ventilation rate is 8-10 sccm, the tetramethylsilane ventilation rate is 0.15-0.4 sccm, the trans-dibutene ventilation rate is 0.3-0.5 sccm, and the coating treatment time is 50-60 minutes.

8. The setter for sintering powder metallurgy products according to claim 5, characterized in that: In step T5, the mass ratio of the sintered corundum powder loaded with silicon coating / organic resin and the zinc salt is 10:2-3, the amounts of the zinc salt and sodium tungstate are equal, and the zinc salt is selected from at least one of zinc chloride, zinc sulfate, and zinc nitrate. The temperature of the hydrothermal reaction is 170-190° C. and the time is 4-6 hours. The temperature of the heating and calcining in step T6 is 1600-1800° C. and the time is 1-3 hours.

9. The setter for sintering powder metallurgy products according to claim 1, characterized in that: The binder is polyvinyl alcohol.

10. A method for preparing a setter for sintering powder metallurgy products according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Treatment of the binder: Prepare the binder into a 10-15 wt% aqueous solution; (2) Making granules: Weigh various raw materials in proportion and put them into a ball mill, add a binder solution, and mill to obtain a mixed slurry. The ball milling medium is high-purity alumina balls, and spray drying is used to make granules. (3) Pressing: Weigh a certain amount of the granulated material prepared in step (2) and pour it into a mold, and press it into a green body at a pressure of 120-160 MPa; (4) Drying and sintering: After the green body is naturally dried for 12-16 hours, it is transferred to an electric heating drying oven for drying at 120-150℃ for 6-12 hours to fully evaporate the moisture therein. Then it is placed in a high-temperature electric furnace and kept at 1600-1700℃ for 6-10 hours. After natural cooling, the sintering plate for powder metallurgy products is obtained.

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