Method for continuously preparing zirconia-based target material by adopting screw extrusion

Abstract

The invention relates to a method for continuously preparing a zirconium oxide-based target material by adopting screw extrusion, which comprises the following steps: using conventional zirconium oxide-based powder and an additive, selecting ceramic powder, grading the grain size of the ceramic powder, selecting organic grains, selecting the additive, mixing the powder, extruding a target material blank, sintering in a low-temperature additive manner, post-processing and the like. The zirconium oxide-based ceramic target material which is large in size, high in purity, high in density and uniform in component can be continuously prepared on a large scale, and is widely applied to technologies such as magnetron sputtering, electron velocity vapor deposition, physical deposition and chemical deposition to prepare thermal barrier coatings, barrier coatings, wear-resistant coatings, corrosion-resistant coatings and the like which are excellent in performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of zirconia-based ceramic target material preparation, and particularly relates to a method for continuously preparing a zirconia-based target material by screw extrusion. BACKGROUND

[0002] Zirconia-based powder generally refers to zirconia ceramic powder doped with yttrium, gadolinium, ytterbium, cerium, magnesium and other elements. Due to its excellent physical and chemical properties, it is prepared into a coating in many fields such as semiconductor and integrated circuit, medical industry, industry and energy, and is used to improve the performance of the base material.

[0003] The zirconia-based target material is a component prepared from zirconia-based ceramic powder, and is a raw material source for forming a coating on a substrate by a magnetron sputtering or deposition technology.

[0004] The magnetron sputtering or deposition technology bombards or irradiates the target material under appropriate process conditions by controlled particles, so that atoms or molecules in the target material are coated on the substrate, and then a coating is formed.

[0005] There are many methods for preparing zirconia-based ceramic target materials, which are generally divided into dry and wet methods. The dry method mainly includes dry pressing, cold isostatic pressing, laser melting and the like. The process is to form a high-purity zirconia-based powder purchased or prepared into a shape by a mold pressing or isostatic pressing method, and to form a dense target material by combining various forms of high-temperature sintering. The dry forming has low cost and is suitable for large-scale production, and is a common target material preparation form at present. The wet forming mainly includes slip casting, sol-gel method, tape casting, hot injection molding, injection molding and the like. The process is to mix a high-purity zirconia-based powder with a solution system by a physical or chemical method, to prepare a slurry or a precursor, to inject the slurry or the precursor into a specially designed mold, to dry the slurry or the precursor to obtain a ceramic green body, and to finally sinter the ceramic green body to form a dense target material. Compared with the dry forming, the wet forming has a complex process flow, a long cycle, is easy to leave residues, and has high requirements for drying and sintering processes.

[0006] Whether the dry forming or the wet forming, the target material forming needs to rely on a mold, and a large number of mold disassembly and assembly processes are inevitably generated. The target material is difficult to meet the production demand of continuous, large-scale and batch production, and the length of the target material is limited by the mold. Once the size of the product changes, the size of the mold needs to be adjusted, and the specifications of the product are single. SUMMARY

[0007] The application gives a method for continuously preparing a zirconia-based target material by screw extrusion, aiming at the problems of expensive production equipment, complex preparation method and inability to mass-produce the zirconia-based target material at the present stage, and the method comprises the following steps.

[0008] Select ceramic powder, standby;

[0009] Select a variety of different specifications of ceramic powder dry grinding mixed to get ceramic graded powder, standby;

[0010] Select organic particles, standby;

[0011] Select additives, standby;

[0012] According to the weight fraction, take ceramic graded powder 100 parts, organic particles 7-12 parts, inorganic additives 1-2 parts; Organic additives 1-3 parts, lubricant 1-2 parts, after mixing, into the screw extruder; Get target material blank; Through the use of different kinds of additives and lubricants, improve the performance of the powder, combined with mixing and extrusion process, ensure that in the use of conventional production materials and equipment, still can continuous preparation of products that meet the requirements.

[0013] Sintering and surface treatment of target material blank to get target material.

[0014] Further, the ceramic powder is selected from one of yttrium stabilized zirconia, gadolinium and ytterbium stabilized zirconia, cerium and yttrium stabilized zirconia powder, with a purity higher than 99.9% and a particle size between 5nm and 500μm.

[0015] Further, the mass ratio of ceramic powder material to grinding ball is between 1 / 2 and 1 / 1, and the ball milling time is 0.5-1h, to get ceramic graded powder standby.

[0016] Further, select one of high purity low density polyethylene, high density polyethylene, polypropylene and other organic particles; Particle size is between 40-60 mesh; Dry the organic particles, drying temperature 60-90℃, drying time 20-24h.

[0017] Further, the inorganic additive is selected from one or more of fluorozirconate, zirconium oxalate, and zirconium oxychloride as an inorganic additive; The organic additive is selected from one or more of zirconium acid tetrabutyl ester, zirconium isopropyl alcohol, and tetra-n-propyl zirconate as an organic additive;

[0018] The lubricant is selected from one of fluorine elastomer, polyethylene wax, and low molecular weight polypropylene;

[0019] Further, the mixing parameters are: hot mixing temperature 150-200℃, cold mixing temperature 50-70℃, high rotation speed 80-100rpm, low rotation speed 30-50rpm, mixing time ball milling time 2h-5h, to get the mixing raw material.

[0020] Further, the extrusion process of the target material blank is as follows:

[0021] According to the size of the target product, the appropriate size of the mold is installed on the screw host, the mold size is Φ85-150mm, the mold heating is started, and the heating temperature of the mold is 170-220℃;

[0022] The screw host heating is opened in sections, the first section temperature is set to 150-210℃, the second section temperature is set to 180-230℃, and the third section temperature is set to 200-250℃, and after the temperature of each section is stable, the next operation is performed;

[0023] The mold pressure is set to 2-8MPa, and the extrusion speed is 0.3-0.7m / s;

[0024] The traction machine height is consistent with the screw host, the traction speed is 0.4-0.8m / s, and the clamping force is 100-200N;

[0025] The cooling water tank pressure is 0.1-0.2Mpa, and the cooling water temperature is 10-20℃;

[0026] According to the length of the product, the target blank is cut to obtain a blank that meets the size requirements;

[0027] Further, in the sintering process, the plant protein foaming agent, the animal protein foaming agent, and the starch are mixed in a mass ratio of 1 / 1 / 1-2 / 2 / 3 to form a low-temperature aid after foaming, which is attached to the outside of the cut target blank, and is loaded into a sintering kiln with a cover.

[0028] Further, the sintering system in the sintering process is two-stage,

[0029] First section: sintering temperature 400-600℃, sintering time 6-8h, 300-500℃ air introduction;

[0030] Second section: sintering temperature 1000-1100℃, sintering time 4-6h, 800-1000℃ air introduction;

[0031] During the sintering process, the low-temperature aid itself expands and generates pressure in the kiln, and at high temperature, the sintering aid and the organic matter in the raw material volatilize into gas to form pressure; the increase of pressure effectively reduces the sintering temperature, delays the grain growth, prevents the crystal phase transition, and ensures the high density of the target after sintering

[0032] During the sintering process, the low-temperature aid expands and discharges, generating pressure itself, and the furnace pressure needs to be monitored, and air needs to be introduced when the furnace pressure is higher than 3MPa to balance the internal and external pressure.

[0033] Furthermore, three different particle sizes of ceramic powder were selected, with the mass ratio of small particles / medium particles / large particles ranging from 2 / 2 / 1 to 4 / 4 / 3 (2:2:1 to 4:4:3). Large, medium, and small particles refer to large, medium, and small particles with significant size differences selected from the available powders ranging from 5nm to 500μm. Specifically, three different particle sizes were selected, with adjacent sizes generally differing by more than 10 times. Through the rational gradation of raw materials, the flowability of the raw materials was improved, and the density of the finished product was increased.

[0034] This invention enables the continuous and large-scale production of zirconia-based ceramic targets with large size, high purity, high density, uniform composition, fine grain size, and single crystal phase, meeting the requirements of processes such as magnetron sputtering, electron velocity vapor deposition, physical deposition, and chemical deposition. It can also produce various zirconia-based functional coatings with excellent performance, such as thermal barrier coatings, barrier coatings, wear-resistant coatings, and corrosion-resistant coatings.

[0035] In summary, the present invention has the following advantages:

[0036] 1. Continuous and mass production via screw extrusion: This invention utilizes screw extrusion technology, employs commercially available raw materials, simple equipment and processes, to continuously and mass-produce zirconia-based ceramic targets, significantly improving production efficiency and reducing production costs.

[0037] 2. Adjustable size: This invention allows for simple and batch adjustment of the blank size by adjusting the die head mold and cutting size according to customer needs, thus producing target products suitable for various magnetron sputtering and deposition equipment.

[0038] 3. Low sintering temperature: This invention adopts low-temperature additive sintering. During the sintering process, the expansion of the additive itself and the gas released increase the sintering pressure, effectively reducing the sintering temperature, lowering production costs, and improving production efficiency. Attached Figure Description

[0039] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of XRD analysis of the three target materials in the example;

[0042] Figure 2 This is a schematic diagram of a yttrium-stabilized zirconia target.

[0043] Figure 3 Schematic diagram of the microstructure of yttrium-stabilized zirconia target material;

[0044] Figure 4 Schematic diagram of the microstructure of gadolinium-ytterbium stabilized zirconia target;

[0045] Figure 5 This is a schematic diagram of a cerium-yttrium stabilized zirconium oxide target. Detailed Implementation

[0046] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of systems consistent with some aspects of the invention as detailed in the appended claims.

[0047] The purpose of this invention is to solve the problems of purity, density, and flowability of zirconia-based powders through research and development of raw materials, equipment, and processes. Using conventional equipment, it aims to reduce production costs and enable the continuous, large-scale preparation of high-performance zirconia-based targets. For details on the crystal phase of the product, please refer to the appendix. Figure 1 Furthermore, through methods such as sputtering or deposition, coatings that can be used for thermal barriers, wear resistance, insulation, etc., can be prepared.

[0048] refer to Figures 1-5 The technical solution of the present invention is achieved through the following means:

[0049] The continuous preparation of zirconia-based targets by screw extrusion mainly includes the following steps: selection of ceramic powder, particle size distribution of ceramic powder, selection of organic particles, selection of additives, mixing of powder, extrusion of target blank, low-temperature sintering with additives, and post-treatment.

[0050] Example 1

[0051] 1 Selection of ceramic powder

[0052] Based on the performance requirements of the target material, different types of yttrium-stabilized zirconia powder with a purity higher than 99.9% and particle sizes D50 of 5nm, 5um, and 500um were selected for use.

[0053] 2. Particle size distribution of ceramic powder

[0054] Based on the particle diameter of the ceramic powder, dry grinding and mixing were carried out using a ball mill according to the mass ratio of small particles / medium particles / large particles = 3 / 2 / 1, with the mass ratio of material to grinding balls being 1 / 1, and the ball milling time being 0.5 hours, to obtain ceramic graded powder for later use.

[0055] 3. Selection of Organic Particles

[0056] Based on the size requirements of the target material, high-purity low-density polyethylene is selected as the organic particles; the particle size is between 50-60 mesh.

[0057] The organic particles were dried at 60℃ for 20 hours.

[0058] 4. Selection of Additives

[0059] Fluorozyric acid was chosen as an inorganic additive.

[0060] Tetrabutyl zirconate and tetra-n-propyl zirconate were selected as organic additives;

[0061] Fluoroelastics were chosen as the lubricant.

[0062] 5. Powder mixing

[0063] 5.1 Mixing raw materials:

[0064] 100 parts of ceramic graded powder, 7 parts of organic particles, 2 parts of inorganic additives, 1 part of organic additives, and 1 part of lubricant are added to a mixer.

[0065] 5.2 Mixing parameters:

[0066] The hot mixing temperature is 150℃, the cold mixing temperature is 50℃, the high speed is 100rpm, the low speed is 50rpm, and the ball milling time is 2h. After obtaining the mixed raw material, it is fed into the screw extruder.

[0067] 6 Extrusion of target preform

[0068] 6.1 Mold:

[0069] According to the size of the target material product, install the appropriate size mold onto the screw host. The mold size is Φ85mm. Start the mold heating. The mold heating temperature is 170-190℃.

[0070] 6.2 Extrusion temperature:

[0071] Turn on the screw compressor heating in stages, setting the temperature of the first stage to 150-180℃, the second stage to 180-200℃, and the third stage to 200-220℃. After the temperature of each stage stabilizes, proceed to the next step.

[0072] 6.3 Pressure and Speed:

[0073] Die pressure 2MPa, extrusion speed 0.5m / s;

[0074] 6.4 Traction: The traction machine height is the same as the screw main unit, the traction speed is 0.6m / s, and the clamping force is 150N. During the traction process, carefully observe whether the traction action is smooth.

[0075] 6.5 Cooling: Cooling water tank pressure 0.15 MPa, cooling water temperature 15℃

[0076] 6.6 Fixed-length cutting: According to the length of the product, the target blank is cut into 250mm sections to obtain blanks that meet the size requirements.

[0077] 7. Low-temperature additive sintering

[0078] 7.1 Low-temperature additives:

[0079] The plant protein foaming agent, animal protein foaming agent, and starch are mixed in a 1:1:1 mass ratio, foamed, and then attached to the outside of the cut target material blank. The blank is then placed into a sintering kiln with a lid on for pressurization.

[0080] 7.2 Sintering parameters: The sintering process is a two-end type.

[0081] First stage: sintering temperature 400℃, sintering time 6h, air introduced at 300℃;

[0082] Second stage: sintering temperature 1000℃, sintering time 5h, air introduced at 900℃;

[0083] 7.3 Pressure regulation: During the sintering process, the furnace pressure is mostly between 1-1.5 MPa. If it exceeds 3 MPa, air needs to be introduced to balance the internal and external pressure.

[0084] 8. Post-processing:

[0085] Yttrium-stabilized zirconia targets with a diameter of 70 mm and a length of 200 mm were obtained through machining.

[0086] Example 2

[0087] 1 Selection of ceramic powder

[0088] Based on the performance requirements of the target material, different types of gadolinium-ytterbium stabilized zirconia powders with a purity higher than 99.9% and particle sizes D50 of 20nm, 2um, and 200um were selected for use.

[0089] 2. Particle size distribution of ceramic powder

[0090] Based on the particle diameter of the ceramic powder, dry grinding and mixing were carried out using a ball mill at a mass ratio of small particles / medium particles / large particles = 2 / 2 / 1, with the material to grinding balls mass ratio of 2 / 3 and the ball milling time of 1 hour, to obtain ceramic graded powder for later use.

[0091] 3. Selection of Organic Particles

[0092] Based on the size requirements of the target material, high-purity high-density polyethylene is selected as the organic particles; the particle size is between 40-50 mesh.

[0093] The organic particles were dried at a temperature of 90℃ for 24 hours.

[0094] 4. Selection of Additives

[0095] Fluorozylic acid and zirconium oxalate were selected as inorganic additives.

[0096] Zirconium isopropoxide and tetra-n-propyl zirconate were selected as organic additives;

[0097] Polyethylene wax was chosen as the lubricant.

[0098] 5. Powder mixing

[0099] 5.1 Mixing raw materials:

[0100] Add 100 parts of ceramic graded powder, 10 parts of organic particles, 1 part of inorganic additive, 2 parts of organic additive, and 2 parts of lubricant to a mixer.

[0101] 5.2 Mixing parameters:

[0102] The hot mixing temperature is 180℃, the cold mixing temperature is 60℃, the high speed is 90rpm, the low speed is 40rpm, and the ball milling time is 3.5h. After obtaining the mixed raw material, it is fed into the screw extruder.

[0103] 6 Extrusion of target preform

[0104] 6.1 Mold:

[0105] According to the size of the target material, install the appropriate size mold onto the screw host. The mold size is Φ150mm. Start the mold heating. The mold heating temperature is 190-210℃.

[0106] 6.2 Extrusion temperature:

[0107] Turn on the screw compressor heating in stages, setting the temperature of the first stage to 180-200℃, the second stage to 200-220℃, and the third stage to 220-240℃. After the temperature of each stage stabilizes, proceed to the next step.

[0108] 6.3 Pressure and Speed:

[0109] Die pressure 5MPa, extrusion speed 0.7m / s;

[0110] 6.4 Traction: The traction machine height is the same as the screw compressor, the traction speed is 0.8 m / s, and the clamping force is 100 N. During the traction process, carefully observe whether the traction action is smooth.

[0111] 6.5 Cooling: Cooling water tank pressure 0.2 MPa, cooling water temperature 20℃

[0112] 6.6 Fixed-length cutting: According to the length of the product, the target blank is cut into 140mm sections to obtain blanks that meet the size requirements.

[0113] 7. Low-temperature additive sintering

[0114] 7.1 Low-temperature additives:

[0115] The plant protein foaming agent, animal protein foaming agent, and starch are mixed in a mass ratio of 2 / 1 / 2 and foamed. The mixture is then applied to the outside of the cut target material blank and placed into a sintering kiln with a lid for pressurization.

[0116] 7.2 Sintering parameters: The sintering process is a two-end type.

[0117] First stage: sintering temperature 500℃, sintering time 7h, air introduced at 400℃;

[0118] Second stage: sintering temperature 1100℃, sintering time 6h, air introduced at 1000℃;

[0119] 7.3 Pressure regulation: During the sintering process, the furnace pressure is mostly between 1.8-2.3 MPa. If it exceeds 3 MPa, air needs to be introduced to balance the internal and external pressure.

[0120] 8. Post-processing:

[0121] Yttrium-stabilized zirconia targets with a diameter of 115 mm and a length of 100 mm were obtained through machining.

[0122] Example 3

[0123] 1 Selection of ceramic powder

[0124] Based on the performance requirements of the target material, different types of cerium-yttrium stabilized zirconia powders with a purity higher than 99.9% and particle sizes D50 of 100nm, 10um, and 100um were selected for use.

[0125] 2. Particle size distribution of ceramic powder

[0126] Based on the particle diameter of the ceramic powder, dry grinding and mixing were carried out using a ball mill at a mass ratio of small particles / medium particles / large particles = 4 / 4 / 3, with the mass ratio of material to grinding balls being 1 / 2 and the ball milling time being 1 hour, to obtain ceramic graded powder for later use.

[0127] 3. Selection of Organic Particles

[0128] Based on the size requirements of the target material, high-purity polypropylene is selected as the organic particles; the particle size is between 40-60 mesh.

[0129] The organic particles were dried at 80℃ for 24 hours.

[0130] 4. Selection of Additives

[0131] Fluorozyric acid, zirconium oxalate, and zirconium oxychloride were selected as inorganic additives.

[0132] Tetrabutyl zirconate and zirconium isopropoxide were selected as organic additives;

[0133] Low molecular weight polypropylene was selected as the lubricant.

[0134] 5. Powder mixing

[0135] 5.1 Mixing raw materials:

[0136] Add 100 parts of ceramic graded powder, 12 parts of organic particles, 1 part of inorganic additive, 3 parts of organic additive, and 1 part of lubricant to a mixer.

[0137] 5.2 Mixing parameters:

[0138] The hot mixing temperature is 200℃, the cold mixing temperature is 70℃, the high speed is 80rpm, the low speed is 30rpm, and the ball milling time is 5h. After obtaining the mixed raw material, it is fed into the screw extruder.

[0139] 6 Extrusion of target preform

[0140] 6.1 Mold:

[0141] According to the size of the target material, install the appropriate size mold onto the screw host. The mold size is Φ125mm. Start the mold heating. The heating temperature of the mold is 200-220℃.

[0142] 6.2 Extrusion temperature:

[0143] Turn on the screw compressor heating in stages, setting the temperature of the first stage to 190-210℃, the second stage to 210-230℃, and the third stage to 230-250℃. After the temperature of each stage stabilizes, proceed to the next step.

[0144] 6.3 Pressure and Speed:

[0145] Die pressure 8MPa, extrusion speed 0.3m / s;

[0146] 6.4 Traction: The traction machine height is consistent with the screw compressor main unit, the traction speed is 0.4m / s, and the clamping force is 200N. During the traction process, carefully observe whether the traction action is smooth.

[0147] 6.5 Cooling: Cooling water tank pressure 0.1 MPa, cooling water temperature 10℃

[0148] 6.6 Fixed-length cutting: According to the length of the product, the target blank is cut into 50mm increments to obtain a blank that meets the size requirements.

[0149] 7. Low-temperature additive sintering

[0150] 7.1 Low-temperature additives:

[0151] The plant protein foaming agent, animal protein foaming agent, and starch are mixed in a mass ratio of 2 / 2 / 3, foamed, and then attached to the outside of the cut target material blank. The blank is then placed into a sintering kiln with a lid on for pressurization.

[0152] 7.2 Sintering parameters: The sintering process is a two-end type.

[0153] First stage: sintering temperature 600℃, sintering time 8h, air introduced at 500℃;

[0154] Second stage: sintering temperature 1000℃, sintering time 4h, air introduced at 800℃;

[0155] 7.3 Pressure regulation: During the sintering process, the furnace pressure is mostly between 2.5-2.8 MPa. If it exceeds 3 MPa, air needs to be introduced to balance the internal and external pressure.

[0156] 8. Post-processing:

[0157] Yttrium-stabilized zirconia targets with a diameter of 100 mm and a length of 20 mm were obtained through machining.

[0158] This invention innovatively applies screw extrusion technology, commonly used in polymer material preparation, to the field of ceramic product manufacturing. By rationally grading the particle size of the raw materials and adding various additives, the performance of the powder is significantly improved. Utilizing the consistent cross-section of the target material, screw extrusion technology enables the large-scale, continuous production of large-size, high-purity zirconia-based ceramic targets, thereby increasing production efficiency. During the sintering process, low-temperature additive-assisted sintering is employed. The expansion and released gases increase the sintering pressure, effectively lowering the sintering temperature and ensuring high target density while reducing production costs.

[0159] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these changes and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for continuously preparing zirconia-based targets using screw extrusion, characterized in that, Includes the following steps: Select ceramic powder and set aside. Ceramic powders of various particle sizes were selected and dry-milled to obtain ceramic graded powders for later use. Select organic granules for later use; Select additives and set aside. According to the specified weight proportions, take 100 parts of ceramic graded powder, 7-12 parts of organic particles, 1-2 parts of inorganic additives, 1-3 parts of organic additives, and 1-2 parts of lubricant, mix them, and then feed them into a screw extruder to obtain a target preform. The target preform is then sintered and surface-treated to obtain the target material. The organic particles are selected from one of high-purity low-density polyethylene, high-density polyethylene, and polypropylene. The inorganic additives are selected from one or more of fluorozirconic acid, zirconium oxalate, and zirconium oxychloride. The organic additives are selected from one or more of tetrabutyl zirconate, zirconium isopropoxide, and tetra-n-propyl zirconate.

2. The method as described in claim 1, characterized in that: The ceramic powder is selected from one of yttrium-stabilized zirconium oxide, gadolinium-ytterbium-stabilized zirconium oxide, and cerium-yttrium-stabilized zirconium oxide powder, with a purity higher than 99.9% and a particle size between 5 nm and 500 μm.

3. The method as described in claim 1, characterized in that: The mass ratio of ceramic powder to grinding balls is between 1 / 2 and 1 / 1, and the ball milling time is 0.5-1 hour to obtain ceramic graded powder for later use.

4. The method as described in claim 1, characterized in that: Depending on the size requirements of the target material, the organic particles should be between 40 and 60 mesh. The organic particles should be dried at a temperature of 60-90℃ for 20-24 hours.

5. The method as described in claim 1, characterized in that: The lubricant should be one of the following: fluoroelastomer, polyethylene wax, or low molecular weight polypropylene.

6. The method as described in claim 1, characterized in that: The mixing parameters are: hot mixing temperature 150-200℃, cold mixing temperature 50-70℃, high speed 80-100rpm, low speed 30-50rpm, and ball milling time 2h-5h to obtain the mixed raw materials.

7. The method as described in claim 1, characterized in that: The extrusion of the target preform is specifically as follows: According to the size of the target material, install the mold onto the screw host. The mold size is Φ85-150mm. Start the mold heating. The mold heating temperature is 170-220℃. Turn on the screw compressor heating in stages, setting the temperature of the first stage to 150-210℃, the second stage to 180-230℃, and the third stage to 200-250℃. After the temperature of each stage stabilizes, proceed to the next step. Set the die pressure to 2-8 MPa and the extrusion speed to 0.3-0.7 m / s; The traction machine is at the same height as the screw main unit, with a traction speed of 0.4-0.8 m / s and a clamping force of 100-200 N; the cooling water tank pressure is 0.1-0.2 MPa, and the cooling water temperature is 10-20℃. The target blank is cut according to the length of the product to obtain a blank that meets the size requirements.

8. The method as described in claim 1, characterized in that: In the sintering process, plant protein foaming agent, animal protein foaming agent, and starch are mixed in a mass ratio of 1 / 1 / 1 to 2 / 2 / 3 to form a low-temperature additive, which is then attached to the outside of the cut target material blank and loaded into the sintering kiln with the lid on for pressurization.

9. The method as described in claim 1, characterized in that: The sintering process involves a two-stage sintering regime. First stage: sintering temperature 400-600℃, sintering time 6-8h, air introduced at 300-500℃; Second stage: sintering temperature 1000-1100℃, sintering time 4-6h, air introduced at 800-1000℃; During the sintering process, the pressure inside the furnace is monitored. If the furnace pressure is higher than 3MPa, air needs to be introduced to balance the internal and external pressures.

10. The method as described in claim 1, characterized in that: Three different sizes of ceramic powder were selected, with the mass ratio of small particles / medium particles / large particles between 2 / 2 / 1 and 4 / 4 / 3. Large, medium and small particles refer to large, medium and small particles with large differences in particle size selected from the available powders between 5nm and 500μm.

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