CN116967441A - Material for powder metallurgy flow pressure swing injection of large component and application thereof - Google Patents

Material for powder metallurgy flow pressure swing injection of large component and application thereof Download PDF

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Publication number
CN116967441A
CN116967441A CN202310873668.6A CN202310873668A CN116967441A CN 116967441 A CN116967441 A CN 116967441A CN 202310873668 A CN202310873668 A CN 202310873668A CN 116967441 A CN116967441 A CN 116967441A
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powder
powder metallurgy
pressure swing
injection material
ceramic
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Inventor
周科朝
曲鹏程
胡宏武
李全林
谢清申
王于兵
熊慧文
张雷
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Yunnan Hongtai New Material Co ltd
Central South University
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Yunnan Hongtai New Material Co ltd
Central South University
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Priority to CN202310873668.6A priority Critical patent/CN116967441A/en
Publication of CN116967441A publication Critical patent/CN116967441A/en
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    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B26/00Compositions of mortars, concrete or artificial stone, containing only organic binders, e.g. polymer or resin concrete
    • C04B26/02Macromolecular compounds
    • C04B26/10Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/10Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
    • B22F1/103Metallic powder containing lubricating or binding agents; Metallic powder containing organic material containing an organic binding agent comprising a mixture of, or obtained by reaction of, two or more components other than a solvent or a lubricating agent
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/10Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
    • B22F1/107Metallic powder containing lubricating or binding agents; Metallic powder containing organic material containing organic material comprising solvents, e.g. for slip casting
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/12Metallic powder containing non-metallic particles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02Compacting only
    • B22F3/03Press-moulding apparatus therefor

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Powder Metallurgy (AREA)

Abstract

The invention provides a powder metallurgy flow variable pressure injection material of a large-sized component and application thereof, wherein the powder metallurgy flow variable pressure injection material consists of raw material powder and an organic binder, and the volume fraction of the raw material powder in the powder metallurgy flow variable pressure injection material is 50% -62%; preferably 55-62%; the material for powder metallurgy flow pressure variable injection of the large component provided by the invention has good fluidity and thermal stability in the flow pressure variable injection process, wherein the organic binder and the material powder have the characteristic of high interface wetting, and the material generates good flow under the action of certain pressure and temperature after being heated to the temperature higher than the softening point of the organic binder, and is injected into a mold cavity through a runner, and the compact filling is carried out, so that a high-uniformity high-density large component blank is obtained, and the densification process is realized.

Description

Material for powder metallurgy flow pressure swing injection of large component and application thereof
Technical Field
The invention belongs to the technical field of powder metallurgy rheological manufacturing, and particularly relates to a powder metallurgy flow pressure swing injection material for a large-sized component and application thereof.
Background
The powder plasticization molding is one of near-net molding methods, and has been widely used in industries such as mechanical manufacturing, medical equipment, electronic information engineering and the like through development, and the powder plasticization molding is characterized in that a polymer binder is mixed with powder, the viscous flow property of a system is endowed above the softening point of the polymer, a green body is obtained through compression molding, and a product is finally obtained through degreasing and sintering. The plasticization molding can be injection molding, extrusion molding and the like according to a green molding mode, wherein the extrusion molding is mainly used for preparing 2D-shaped pipes and sheets, the powder injection molding is the technology which has the widest application range and the most mature at present, a screw of an injection molding machine drives a feed to be extruded into a mold cavity and can be used for molding some small and medium-sized components, but the molding of large-sized components is difficult, the powder injection molding requires a feed with better fluidity, the too high viscosity can cause blockage of an extrusion head and influence the molding quality, the volume fraction of powder in the feed is always lower than 60vol percent for improving the viscosity of the feed, the problem that the line shrinkage of a blank body is larger after sintering, and the degreasing is incomplete due to the too high binder component when the blank body is used for coping with the large-sized components is also caused, and in addition, the molding of the large-sized components has higher requirements on injection molding equipment, so that the production cost is improved.
Disclosure of Invention
The invention aims at providing a powder metallurgy flow pressure swing injection material for a large-scale component.
The second object of the invention is to provide an application of the powder metallurgy flow pressure swing injection material of the large-scale component.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the invention relates to a powder metallurgy flow variable pressure injection material of a large-sized component, which consists of raw material powder and an organic binder, wherein the volume fraction of the raw material powder in the powder metallurgy flow variable pressure injection material is 50% -62%; preferably 55-62%; the raw material powder is at least one of metal powder, ceramic powder and metal ceramic composite powder, and the organic binder comprises the following components in percentage by volume: 65-90vol% of filling binder, 5-35vol% of backbone binder, 2-5vol% of surfactant and 0-5% of additive; the melt index of the filling binder is more than or equal to 80g/min, and the melt index of the backbone binder is more than or equal to 35g/min.
The material for powder metallurgy flow pressure-variable injection of the large-sized component has good fluidity and thermal stability in the rheological pressure injection process, wherein the organic binder and the raw material powder have the characteristic of high interface wetting, the volume fraction of the raw material powder is higher than that of the raw material powder, but the raw material powder has low binder content, the strength of a blank can be kept better, good flow is generated under the action of a certain pressure and temperature when the raw material powder is heated to be above the softening point temperature of the organic binder, the material is injected into a mold cavity through a runner, the density uniformity and the surface quality of a molded blank obtained by compact mold filling are good, a communicated degreasing channel is provided, the full efficient degreasing of the large-sized component can be realized, and the line shrinkage of the product after degreasing sintering of the blank is lower than that of the traditional powder plasticization molding and the dimensional precision is higher due to the high solid phase ratio.
The binder for powder metallurgy flow pressure-variable injection materials adopts high filling binder content, provides blank strength by a small amount of proper backbone binder, forms a communication channel by filling a large amount of binder, realizes high-efficiency complete degreasing of large parts, and enables binder components to be removed more easily and rapidly based on the smaller binder, meanwhile, the powder solid phase content is improved, the line shrinkage of sintering molding is reduced, and the dimensional accuracy is controlled better.
Preferably, the powder metallurgy flow pressure swing injection material has a shear rate of 100S when the temperature is 10-50 ℃ above the softening point -1 The viscosity number of the feed is, in the case of the feed, 200 to 1000 Pa.S, preferably 50 to 400 Pa.S.
When the viscosity of the powder metallurgy flowing pressure injection material is too high (more than 1000 Pa) at 10-50 ℃ above the softening point, the fluidity is poor, the density uniformity of a formed blank body can be reduced, the density difference value of each part is more than 1.5wt%, the blank body is easy to deform after sintering, and the dimensional stability is poor; when the viscosity of the powder metallurgy flowing pressure variable injection material is too small (less than 20 Pa), the fluidity is too high, the content of the binder in the formed blank body is too high, the forming pressure of the formed blank body can be reduced, air holes are easy to remain in the formed blank body, the difficulty in removing the binder at the later stage of sintering is high, and the large-size blank is easy to crack in the sintering process.
The density uniformity of each part of the green body after the powder metallurgy flow pressure swing injection material is formed is high, the density difference value of each part is less than or equal to 1.5wt percent, and the preferential scheme is less than or equal to 0.8wt percent; the material has better heat stability, and the mass loss of the material is less than or equal to 1.0wt% and is less than or equal to 0.6wt% in the preferable scheme under the condition that the temperature is 10-50 ℃ higher than the softening point of the binder and the heat is preserved for 60 min.
In a preferred embodiment, when the raw material powder is a metal powder, the particle size of the metal powder is 5 to 100. Mu.m, preferably 10 to 50. Mu.m. Because the material of the invention has high ratio of raw material powder and higher powder loading, the sintering shrinkage rate is relatively low, and the sintering activity requirement on the powder is lower, the raw material powder with larger particle size compared with injection molding can be adopted, the oxygen content is low, the fluidity is higher, the precision of the finished product obtained by cooperative rheological pressure injection molding is higher, the performance is better, and the cost is lower.
Further preferably, the metal powder is spherical. The spherical gold powder is prepared by methods of water atomization, gas atomization, plasma spheroidization and the like.
Further preferably, the metal powder is composed of fine particles having a particle diameter of 5 to 20 μm and coarse particles having a particle diameter of 30 to 50 μm, wherein the mass ratio of the coarse particles to the fine particles is 5 to 9:1 to 5. Through the collocation of coarse and fine particles, the volume content of powder can be further improved, and the size control precision of the flow pressure swing injection molded product is improved.
Preferably, when the raw material powder is selected from ceramic powder or cermet composite powder, the particle size of the ceramic powder or cermet composite powder is 20-500 μm, preferably 50-200 μm; the ceramic powder is obtained by spheroidizing ceramic fine powder with the particle size of 0.05-10 mu m, preferably 0.5-5 mu m, and the metal ceramic composite powder is obtained by spheroidizing ceramic fine powder with the particle size of 0.05-10 mu m, preferably 0.5-5 mu m and metal fine powder.
Further preferably, the ceramic powder is obtained by the following steps: and mixing the ceramic fine powder with the binding agent A, and then performing spheroidization granulation and presintering, wherein the ratio of the presintering temperature T1 to the sintering temperature T0 of a blank sintered product obtained after the powder metallurgy flow pressure swing injection material is pressed and formed is 0.6-0.9, and preferably 0.7-0.8.
Still more preferably, the addition amount of the binder a is 0.5 to 3.0wt% of the ceramic fine powder, and the binder a is at least one selected from paraffin wax, carnauba wax, microcrystalline wax, polyethylene glycol, polyvinyl alcohol, methyl cellulose, and rubber.
In the actual operation process, the mode of mixing the ceramic fine powder and the binding agent A is wet ball milling or stirring, and the spheroidizing and granulating process is spray granulation, ultrasonic spray drying, other drying spheroidizing processes and the like.
Further preferably, the metal ceramic composite powder is obtained by the following steps: mixing ceramic fine powder, metal fine powder and a bonding agent B, and then spheroidizing, granulating and presintering to obtain the powder metallurgy flow pressure swing injection material, wherein the ratio of the presintering temperature T1 to the sintering temperature T0 of a blank sintering product obtained after the powder metallurgy flow pressure swing injection material is pressed and molded is 0.6-0.9, and preferably 0.7-0.8.
The metal ceramic composite powder obtained by the spheroidizing treatment has high fluidity and certain strength, so that the ball form of the powder is kept in the mixing process of the metal ceramic composite powder and the binder, the metal ceramic composite powder cannot be sheared and broken, the presintering temperature is controlled within the ratio range, and the metal ceramic composite powder has high sintering activity and high strength.
Still more preferably, the particle diameters of the ceramic fine powder and the metal fine powder are 0.05-10 μm, preferably 0.5-5 μm, and the addition amount of the binding agent B is 0.5-3.0wt% of the total mass of the ceramic fine powder and the metal fine powder, and the binding agent is at least one selected from paraffin wax, carnauba wax, microcrystalline wax, polyethylene glycol, polyvinyl alcohol, methyl cellulose and rubber.
In the actual operation process, the mode of mixing the ceramic fine powder, the metal fine powder and the bonding agent B is wet ball milling or stirring, and the spheroidizing and granulating process is spray granulation, ultrasonic spray drying, other drying spheroidizing processes and the like.
Preferably, the organic binder comprises the following components in percentage by volume: 70-80vol% of filling binder, 12-27vol% of backbone binder, 3-5vol% of surfactant and 0-3% of additive. By adopting the organic binder under the preferable formula, the obtained powder metallurgy material for the flow pressure injection has optimal performance after the flow pressure injection sintering.
Preferably, the organic binder comprises the following components in percentage by volume: 75-80vol% of filling binder, 12-15vol% of backbone binder, 3-5vol% of surfactant and 2-3% of additive.
Preferably, the filling binder is at least one selected from paraffin wax, carnauba wax, microcrystalline wax, beeswax, polyethylene wax, polyoxymethylene, polyethylene glycol,
the backbone binder is at least one selected from polypropylene, polyethylene, polystyrene, polymethyl methacrylate and ethylene-vinyl acetate copolymer,
the surfactant is at least one of stearic acid, zinc stearate, glycerol, castor oil and peanut oil;
the additive is selected from plasticizer and/or antioxidant, preferably plasticizer, wherein the plasticizer is selected from at least one of dibutyl phthalate, dioctyl phthalate, isooctyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol 4[ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], n-stearyl 4,4' -methylenebis (2, 6-di-tert-butylphenol), 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, and the antioxidant is selected from one or more of antioxidant A1010, stabilizer A10, irganox245, irganox 259. In a preferred scheme, the morphology of the powder metallurgy flow pressure swing injection material is at least one of cylindrical particles, powder and blocks, and the blocks are at least one of round hole-containing wafers, blocks and honeycomb blocks, and preferably honeycomb blocks.
The inventor finds that the powder metallurgy flow pressure-variable injection materials with the three shapes have good filling effect, and when the powder metallurgy flow pressure-variable injection materials are blocks, especially honeycomb blocks, heating rods can be inserted into all pores of the honeycomb blocks so as to realize rapid and uniform heating of large-volume materials, the material preheating process time is less than or equal to 30min, the loss of binders in the materials caused by overlong time can be prevented, and the process stability of flow pressure-variable injection molding is reduced.
Further preferably, when the powder metallurgy stream pressure injection material is cylindrical particles, the diameter is 0.5-3mm, preferably 1-2mm; a length of 1-5mm, preferably 2-4mm
Further preferably, when the powder metallurgy flow pressure swing injection material is cylindrical particles, the obtaining process includes mixing raw material powder and an organic binder to obtain a material mass, and extruding and granulating the material mass by a screw granulator to obtain the cylindrical material mass.
Specifically, mixing the binder and the powder means that when the melting point of the polymer is higher, placing the powder and the polymer binder in an internal mixer or a stirrer in batches for heating and mixing for a period of time to obtain a uniformly mixed bulk material.
Further preferably, when the powder metallurgy flux pressure swing injection material is a powder, the particle size is-10 to-200 mesh, preferably-20 to-100 mesh.
Further preferably, when the morphology of the powder metallurgy flow pressure swing injection material is powder, the obtaining process comprises the steps of mixing the raw material powder and the organic binder to obtain a material mass, and crushing the material mass by a crusher.
Further preferably, when the powder metallurgy flow pressure swing injection material is a block, the material powder and the organic binder are mixed to obtain a material block, and the material block is subjected to hot press molding in a mold to obtain the powder metallurgy flow pressure swing injection material.
The invention also provides application of the powder metallurgy flow variable pressure injection material, which is applied to obtaining a large-sized component through powder metallurgy flow variable pressure injection.
The application process comprises the following steps of: firstly preheating a material to a temperature 10-50 ℃ higher than the softening point of the material, then injecting the material into a mould preheated to a temperature 10-50 ℃ higher than the softening point of the material through a flow channel under a pressure of 20-200 MPa, then maintaining the pressure for 1-60min, stopping heating the mould, cooling the mould, demoulding after the blank is solidified to obtain a large-sized component blank, and sintering the large-sized component blank to obtain the large-sized component.
And cooling the die, solidifying the blank, demolding to obtain a large-sized blank, degreasing and sintering to obtain the large-sized member.
The large-sized component in the invention means that the weight of the component is more than or equal to 2.0kg, and the maximum wall thickness of the component is more than or equal to 15mm.
Principles and advantages of the present invention:
the invention relates to a powder metallurgy flow pressure-variable injection material for a large-sized component, which is prepared by mixing spherical or nearly spherical powder with a binder system with good affinity and then preparing the mixture, and the mixture can be subjected to regulation and control by additives to obtain the flow pressure-variable injection material with moderate viscosity, compact mold filling, uniform two-phase dispersion and good degreasing channel. The invention has the following advantages: 1) The powder spheroidizing pretreatment technology comprises the steps of granulating and presintering spherical powder of ceramic and metal ceramic composite powder, mixing the spherical powder with a binder to be suitable for feeding design, effectively improving the volume fraction of the powder and the rheological property of the feeding, improving the dispersion uniformity of two phases of the powder binder, realizing a good degreasing channel of a component, realizing high-efficiency complete degreasing of a large-size component, reducing the line shrinkage of a sintered product and improving the dimensional accuracy; 2) High powder loading capacity, and high-temperature rheological injection can be combined to realize precise sintering of large parts; 3) The high filling adhesive content, a small amount of proper backbone adhesive is used for providing the strength of the blank, and a large amount of filling adhesive forms a communication channel, so that the high-efficiency complete degreasing of the large-scale component is realized; 4) The method is suitable for different formed material forms, heating holes are reserved, and the material can quickly reach the forming temperature after the heating rod is inserted.
Through tests, the material disclosed by the invention can realize powder metallurgy flow pressure variable injection molding of metal, ceramic and metal ceramic materials of large-scale parts, the binder component is effectively and completely removed, and the sintered product has good size, uniform structure and controllable object image and has good sintering density.
The material for powder metallurgy flow pressure swing injection is applied to powder metallurgy flow pressure swing injection, combines the advantages of powder plasticization molding and compression molding, realizes uniform densification molding of high-powder-density feeding, improves the dimensional accuracy of products, and reduces the cost.
Drawings
FIG. 1 is a flow chart of the preparation of a material for rheologic injection.
FIG. 2 is a schematic diagram of different forms of materials.
Fig. 3 is a green and sintered morphology of the stainless steel part of example 1.
Fig. 4 is an SEM morphology of the spheroidizing pretreatment of the cermet of example 2.
Detailed Description
Example 1.
1. The formula comprises the following components:
metal powder and particle size composition: 316L stainless steel powder is selected, the grain diameter is 50 mu m and 5 mu m respectively, and the mass ratio of coarse powder to fine powder is: 40%:60%.
Polymer binder composition: the polymer filling component A is polyoxymethylene, the polymer backbone component B is polystyrene, the surfactant component C is stearic acid, the plasticizer D is dioctyl phthalate, and the volume percentage is: polyoxymethylene: polystyrene: stearic acid: dioctyl phthalate = 80%:12%:5%:3%
During the mixing process, 60vol% of stainless steel powder and 40vol% of polymer binder are added.
2. And (3) material preparation:
(1) And (3) stainless steel powder particle size grading treatment: and pouring the stainless steel coarse particles and the fine particles into a V-shaped ball milling tank for mixing for 1h, wherein the rotating speed is 30r/min.
(2) Mixing of powder with binder: and (3) pouring the stainless steel powder obtained in the step (1) into a preheated internal mixer, continuously drying for 1h, adding a binder component and metal powder according to a feeding ratio, and mixing at 180 ℃ for 45min.
(3) And (3) material preparation: and placing the mixed material mass into a molding press, and performing hot pressing to obtain the honeycomb feed, wherein the molding temperature is 180 ℃ and the pressure is 5Mpa.
The mass was at 190℃C (about 30℃above the softening point temperature) and the mass was at 100S -1 The viscosity thereof was 200Pa at the shear rate; the density uniformity of each part of the blank body after the material is formed is high, and the density difference value of each part is less than or equal to 0.5wt%; the material has better heat stability, and the mass loss of the material is less than or equal to 0.4wt% when the material is insulated for 60 minutes under the condition that the temperature is 10-50 ℃ higher than the softening point of the binder.
3. Application effect of materials
Firstly preheating a material to a temperature 20 ℃ higher than the softening point of the material, then injecting the material into a die preheated to a temperature 20 ℃ higher than the softening point of the material through a flow channel under a pressure of 100MPa, and then carrying out pressure maintaining for 40min. As shown in figure 3, after the above-mentioned bad materials are injected by means of flow pressure and pressure, the blank body with good surface quality, compactness and uniformity is obtained, and after the preliminary degreasing, the polyformaldehyde component is completely removed, and after the above-mentioned blank material is sintered at 1350 deg.C, the product has no crack, high size accuracy and uniform structure. The relative density of the obtained finished product is 97.5%, the tensile strength is 520MPa, and the dimensional accuracy reaches +/-0.8 mm/100mm.
Example 2.
1. The formula comprises the following components:
cermet powder and particle size composition: selecting Cu-Ni powder with the average grain diameter of 30 mu m and nickel ferrite powder with the average grain diameter of 1 mu m, wherein the proportion of a metal phase to a ceramic phase is as follows: 30%:70%.
Polymer binder composition: the polymer filling component A is paraffin, the polymer backbone component B is polypropylene and polystyrene, and the surfactant component C is stearic acid. The volume percentage is as follows: paraffin wax: polypropylene: polystyrene: stearic acid=70%: 20%:7%:3%.
During the mixing process, 56vol% of metal ceramic powder and 44vol% of polymer binder are added.
2. And (3) material preparation:
(1) Spheroidizing pretreatment of metal ceramic powder: pouring the ceramic powder into a ball milling tank for ball milling for 24 hours, wherein the rotating speed is 120r/min, adding polyethylene wax accounting for 2wt% of the powder mass, and drying and granulating after ball milling is finished to obtain spherical granules with the average particle size of 100 mu m as shown in figure 4; followed by pre-sintering of the pellets, the pre-sintering temperature T 1 900, T 1 /T 0 0.75.
(2) Mixing of powder with binder: pouring the metal ceramic powder obtained in the step (1) into a preheated internal mixer, continuously drying for 1h, adding a binder component and the metal powder according to the feeding ratio, and mixing at 160 ℃ for 45min.
(3) And (3) material preparation: and (3) putting the mixed material mass into a screw extrusion granulation set for granulation, and cutting in an extrusion head to obtain a short cylindrical granular material with the diameter of 2mm and the length of 4mm, wherein the macroscopic morphology of the material is shown in figure 2 a.
The mass was at 160℃and about 40℃above the softening point temperature, the mass was at 100S -1 At the shear rate of (2) its viscosity50Pa; the density uniformity of each part of the blank body after the material is formed is high, and the density difference value of each part is less than or equal to 0.8wt%; the material has better heat stability, and the mass loss of the material is less than or equal to 0.5wt% when the temperature is 40 ℃ higher than the softening point of the binder and the temperature is kept for 60 min.
3. Application effect of materials
Firstly preheating a material to a temperature 20 ℃ higher than the softening point of the material, then injecting the material into a die preheated to a temperature 40 ℃ higher than the softening point of the material through a flow channel under a pressure of 50MPa, and then maintaining the pressure for 10min. As shown in figure 3, after the above metal ceramic material is subjected to flow pressure swing injection, a blank body with good surface quality, compactness and uniformity is obtained, components are removed completely after degreasing, and the product is free from cracking, high in dimensional accuracy and uniform in structure after sintering at 1200 ℃.
The relative density of the obtained finished product is 95.8%, the bending strength is 340MPa, and the dimensional accuracy reaches +/-1.2 mm/100mm.
Example 3
1. The formula comprises the following components:
ceramic powder and particle size composition: siC powder with average grain diameter of 0.5 μm is selected and added with 2wt% of Y 2 O 3 The average particle diameter of the powder was 0.2. Mu.m.
Polymer binder composition: the polymer filling component A is polyethylene glycol, the polymer backbone component B is high-density polyethylene and polypropylene, and the surfactant component C is ethylene bis stearamide. The volume percentage is as follows: polyethylene glycol: high density polyethylene: polypropylene: ethylene bis stearamide = 70%:20%:7%:3%.
Ceramic powder with the volume content of 58vol% and polymer binder with the volume content of 42vol% are added in the mixing process.
2. And (3) material preparation:
(1) Spheroidizing pretreatment of ceramic powder: pouring the ceramic powder into a ball milling tank for ball milling for 24 hours, wherein the rotating speed is 120r/min, adding polyethylene wax accounting for 2wt% of the powder mass, and drying and granulating after ball milling is finished to obtain spherical granules with the average particle size of 50 mu m; followed by pre-sintering of the pellets, the pre-sintering temperature T 1 1600, T 1 /T 0 0.84.
(2) Mixing of powder with binder: pouring the ceramic powder obtained in the step (1) into a preheated internal mixer, continuously drying for 1h, adding a binder component and metal powder according to the mixture ratio, and mixing at 150 ℃ for 45min.
(3) And (3) material preparation: and cooling the banburying material, and crushing by an internal mixer.
The mass was at 150℃and about 30℃above the softening point, the mass was at 100S -1 The viscosity thereof was 100Pa at the shear rate; the density uniformity of each part of the blank body after the material is formed is high, and the density difference value of each part is less than or equal to 0.6wt%; the material has better heat stability, and the mass loss of the material is less than or equal to 0.8wt% when the temperature is 40 ℃ higher than the softening point of the binder and the temperature is kept for 60 min.
3. Application effect of materials
Firstly preheating a material to a temperature 10 ℃ higher than the softening point of the material, then injecting the material into a die preheated to a temperature 20 ℃ higher than the softening point of the material through a flow channel under a pressure of 40MPa, and then maintaining the pressure for 30min.
After the ceramic material is subjected to flow pressure swing injection, a compact and uniform blank body with good surface quality is obtained, the components of polyoxymethylene are removed completely after preliminary degreasing, and the product is free from cracking, high in dimensional accuracy and uniform in structure after sintering at 1800 ℃.
The relative density of the obtained finished product is 97.2%, the bending strength is 460MPa, and the dimensional accuracy reaches +/-1.0 mm/100mm.
Comparative example 1
1. The formula comprises the following components:
metal powder and particle size composition: stainless steel powder with average grain diameter of 30 mu m is selected
Polymer binder composition: the polymer filling component A is polyoxymethylene, the polymer backbone component B is polystyrene, and the surfactant component C is stearic acid. The mass percentage is as follows: polyoxymethylene: polystyrene: stearic acid: dioctyl phthalate = 80%:12%:5%: during the 3% mixing process, 60vol% stainless steel powder and 40vol% polymer binder were added.
2. And (3) material preparation:
(1) Mixing of powder with binder: and (3) pouring the stainless steel powder obtained in the step (1) into a preheated internal mixer, continuously drying for 1h, adding a binder component and metal powder according to a feeding ratio, and mixing at 180 ℃ for 45min.
(2) And (3) material preparation: and placing the mixed material mass into a molding press, and performing hot pressing to obtain the honeycomb feed, wherein the molding temperature is 180 ℃ and the pressure is 5Mpa.
3. Application effect of materials
After the stainless steel material is subjected to flow pressure swing injection, a blank body with good surface quality, compactness and uniformity is obtained, and similar to the blank body shown in fig. 3, the polyoxymethylene components are completely removed after preliminary degreasing, and the sintered product is free from cracking, high in dimensional accuracy and uniform in structure. Other conditions of this comparative example were the same as in example 1 except that the metal raw materials were coarse powders, and the sintering activity of the blank was inferior to that of example 1, resulting in a lower sintered relative density of the comparative example member. The relative density of the obtained finished product is 93.2%, the tensile strength is 330MPa, and the dimensional accuracy reaches +/-2.0 mm/100mm.
Comparative example 2.
Cermet powder and particle size composition: selecting Cu-Ni powder with the average grain diameter of 30 mu m and nickel ferrite powder with the average grain diameter of 1 mu m, wherein the proportion of a metal phase to a ceramic phase is as follows: 30%:70%.
Polymer binder composition: the polymer filling component A is paraffin, the polymer backbone component B is polypropylene and polystyrene, and the surfactant component C is stearic acid. The volume percentage is as follows: paraffin wax: polypropylene: polystyrene: stearic acid=70%: 20%:7%:3%.
During the mixing process, 56vol% of metal ceramic powder and 44vol% of polymer binder were added.
2. And (3) material preparation:
(1) Mixing of powder with binder: pouring the metal ceramic powder into a preheated internal mixer, continuously drying for 1h, adding the binder component into the internal mixer according to the mixture ratio, and mixing the binder component and the metal powder, wherein the mixing temperature is 160 ℃, and the mixing time is 45min.
(2) And (3) material preparation: and (3) putting the mixed material mass into a screw extrusion granulation set for granulation, and cutting in an extrusion head to obtain a short cylindrical granular material with the diameter of 2mm and the length of 4mm, wherein the macroscopic morphology of the material is shown in figure 2.
3. Application effect of materials
After the metal ceramic material is subjected to flow pressure swing injection, a compact and uniform blank body with good surface quality is obtained, polymer components are not completely removed after degreasing, and a sintered product is cracked.
Comparative example 3.
1. The formula comprises the following components:
SiC powder with average grain diameter of 0.5 μm is selected and added with 2wt% of Y 2 O 3 The average particle diameter of the powder was 0.2. Mu.m.
Polymer binder composition: the polymer filling component A is polyethylene glycol, the polymer backbone component B is high-density polyethylene and polypropylene, and the surfactant component C is ethylene bis stearamide. The volume percentage is as follows: polyethylene glycol: high density polyethylene: polypropylene: ethylene bis stearamide = 70%:20%:7%:3%.
During the mixing process, ceramic powder with the volume content of 45vol% and polymer binder with the volume content of 55vol% are added.
2. And (3) material preparation:
(1) Spheroidizing pretreatment of ceramic powder: pouring the ceramic powder into a ball milling tank for ball milling for 24 hours, wherein the rotating speed is 120r/min, adding polyethylene wax accounting for 2wt% of the powder mass, and drying and granulating after ball milling is finished to obtain spherical granules with the average particle size of 100 mu m; followed by pre-sintering of the pellets, the pre-sintering temperature T 1 1600, T 1 /T 0 0.84.
(2) Mixing of powder with binder: pouring the ceramic powder obtained in the step (1) into a preheated internal mixer, continuously drying for 1h, adding a binder component and metal powder according to the mixture ratio, and mixing at 150 ℃ for 45min.
(3) And (3) material preparation: and cooling the banburying material, and crushing by an internal mixer.
3. Application effect of materials
This comparative example 3 is the same as example 3 except that the ratio of the raw material powder is too low, the ceramic material is extruded from the die during the rheological injection, the surface quality of the molded green body is good, the polymer component is completely removed after degreasing, and the shrinkage of the sintered product is large and the structure is general.

Claims (10)

1. A powder metallurgy flow pressure swing injection material for a large component is characterized in that: the powder metallurgy flow pressure-variable injection material consists of raw material powder and an organic binder, wherein the volume fraction of the raw material powder in the powder metallurgy flow pressure-variable injection material is 50% -62%; the raw material powder is at least one of metal powder, ceramic powder and metal ceramic composite powder, and the organic binder comprises the following components in percentage by volume: 65-90vol% of filling binder, 5-35vol% of backbone binder, 2-5vol% of surfactant and 0-5% of additive; the melt index of the filling binder is more than or equal to 80g/min, and the melt index of the backbone binder is more than or equal to 35g/min.
2. A powder metallurgy flux pressure swing injection material for a large component according to claim 1, wherein: when the powder metallurgy flow pressure swing injection material is 10-50 ℃ above the softening point, the shearing rate is 100S -1 The viscosity value of the feed is 200-1000 Pa.S.
3. A powder metallurgy flux pressure swing injection material for large scale components according to claim 1 or 2, characterized in that: the metal powder consists of fine particles with the particle size of 5-20 mu m and coarse particles with the particle size of 30-50 mu m, wherein the mass ratio of the coarse particles to the fine particles is 5-9: 1 to 5.
4. A powder metallurgy flux pressure swing injection material for large scale components according to claim 1 or 2, characterized in that: when the raw material powder is selected from ceramic powder or metal ceramic composite powder, the particle size of the ceramic powder or metal ceramic composite powder is 20-500 mu m, the ceramic powder is obtained by spheroidizing ceramic fine powder with the particle size of 0.05-10 mu m, and the metal ceramic composite powder is obtained by spheroidizing ceramic fine powder with the particle size of 0.05-10 mu m and metal fine powder.
5. A powder metallurgy flux pressure swing injection material for a large component according to claim 4, wherein:
the ceramic powder is obtained by the following steps: mixing ceramic fine powder with a bonding agent A, performing spheroidization granulation and presintering to obtain the ceramic powder, wherein the ratio of the presintering temperature T1 to the sintering temperature T0 of a blank sintered product obtained after the powder metallurgy flow pressure swing injection material is pressed and molded is 0.6-0.9,
the addition amount of the binding agent A is 0.5-3.0wt% of the ceramic fine powder, and the binding agent A is at least one selected from paraffin wax, carnauba wax, microcrystalline wax, polyethylene glycol, polyvinyl alcohol, methyl cellulose and rubber;
the metal ceramic composite powder is obtained by the following steps: mixing ceramic fine powder, metal fine powder and a bonding agent B, and then spheroidizing, granulating and presintering to obtain the ceramic powder, wherein the ratio of the presintering temperature T1 to the sintering temperature T0 of a blank sintered product obtained after the powder metallurgy flow pressure swing injection material is pressed and molded is 0.6-0.9,
the addition amount of the bonding agent B is 0.5-3.0wt% of the total mass of the ceramic fine powder and the metal fine powder, and the bonding agent is at least one selected from paraffin wax, carnauba wax, microcrystalline wax, polyethylene glycol, polyvinyl alcohol, methyl cellulose and rubber.
6. A powder metallurgy flux pressure swing injection material for large scale components according to claim 1 or 2, characterized in that:
the organic binder comprises the following components in percentage by volume: 70-80vol% of filling binder, 12-27vol% of backbone binder, 3-5vol% of surfactant and 0-3% of additive.
7. A powder metallurgy flux pressure swing injection material for large scale components according to claim 1 or 2, characterized in that:
the filling binder is at least one selected from paraffin wax, carnauba wax, microcrystalline wax, beeswax, polyethylene wax, polyoxymethylene and polyethylene glycol,
the backbone binder is at least one selected from polypropylene, polyethylene, polystyrene, polymethyl methacrylate and ethylene-vinyl acetate copolymer,
the surfactant is at least one of stearic acid, zinc stearate, glycerol, castor oil and peanut oil;
the additive is selected from at least one of dibutyl phthalate, dioctyl phthalate, beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid isooctyl ester, 4[ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, 4' -methylenebis (2, 6-di-tert-butylphenol) and 3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid n-stearyl alcohol ester, and/or an antioxidant, wherein the antioxidant is selected from one or more of antioxidant A1010, stabilizer A10, irganox245 and Irganox 259.
8. A powder metallurgy flux pressure swing injection material for large scale components according to claim 1 or 2, characterized in that: the shape of the powder metallurgy flow pressure swing injection material is at least one of cylindrical particles, powder and blocks, the blocks are at least one of round hole-containing wafers, blocks and honeycomb blocks,
when the powder metallurgy flow pressure swing injection material is cylindrical particles, the diameter is 0.5-3mm, the length is 1-5mm,
when the powder metallurgy flow pressure swing injection material is powder, the particle size is-10 to-200 meshes, preferably-20 to-100 meshes.
9. Use of a powder metallurgy flux pressure swing injection material for large scale structures according to any one of claims 1 to 8, characterized in that: the powder metallurgy flow injection material is applied to the large-scale component obtained through powder metallurgy flow injection.
10. The use of a large component powder metallurgy flux pressure swing injection material according to claim 9, wherein: the application process comprises the following steps: firstly preheating a material to a temperature 10-50 ℃ higher than the softening point of the material, then injecting the material into a mould preheated to a temperature 10-50 ℃ higher than the softening point of the material through a flow channel under a pressure of 20-200 MPa, then maintaining the pressure for 1-60min, stopping heating the mould, cooling the mould, demoulding after the blank is solidified to obtain a large-sized component blank, and sintering the large-sized component blank to obtain the large-sized component.
CN202310873668.6A 2023-07-17 2023-07-17 Material for powder metallurgy flow pressure swing injection of large component and application thereof Pending CN116967441A (en)

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