WO2005011900A1

WO2005011900A1 - Molding composition for powder sintering, method of sintering powder for sintering, and sinter member made from the powder

Info

Publication number: WO2005011900A1
Application number: PCT/JP2003/009905
Authority: WO
Inventors: Akira Yotsutsuji
Original assignee: Coki Engineering Inc.
Priority date: 2003-08-04
Filing date: 2003-08-04
Publication date: 2005-02-10
Also published as: AU2003254804A1

Abstract

A composition characterized by comprising: a binder resin comprising a solvent-soluble resin and a solvent-insoluble resin incorporated therein; and a powder for sintering which has been fixed to the binder resin. When this composition is used to form a green molding and the solvent-soluble resin ingredient only is removed from the green molding, then the solvent-insoluble resin ingredient remains to maintain the shape of the green molding. Although this green molding is porous, it is prevented from deforming over the period of from the sufficient degreasing to a sintering step. The degreased green molding is hence significantly easy to handle, and the sinter which is being produced does not deform during sintering.

Description

Molding composition for powder sintering, method of sintering powder for sintering, and powder sintered member thereof

The present invention relates to an innovative powder sintering method, a molding composition for powder sintering to be subjected to the method, and a powder sintered member thereof.

Bright

Background art

Conventionally, powder sintering method is injection molding using a mixture of powder for sintering and a polyacetal resin as pine resin as a raw material, and degreasing the green body formed by injection molding with nitric acid to obtain a powder sintered member Chemical methods such as patent No. 2602 769 of forming a high pressure pressing method in which the powder material is put into a mold and subjected to high pressure pressing, a binder material such as paraffin for the powder for sintering described above The mixture with the above is placed in a rubber bag, and this is pressed in a water tank to form a single compressed rod body (Laper press method), and then the shape required for the shrinkage rate during sintering is expected. The compacted rod is roughly processed into a substantially similar shape, and the roughly processed product is heated to gradually remove the binder from the roughly processed product (semi-sintering). Need to be fused in a porous state) There have been proposed methods of processing the portion further and finally sintering it to form a powder-sintered member and many other methods.

However, there are various problems as described below in any of the conventional methods. That is, in the chemical method using polyacetal resin as the binder resin, there is a problem that dangerous chemicals such as nitric acid must be used in the manufacturing process, · When using the binder resin, the green body in the degreasing process The problem of strain generation during sintering due to uneven degreasing of the pin resin (in other words, while degreasing is easily performed on the part near the surface or thin part, degreasing is performed on the central part or thick part) It is hard to be removed, and even after degreasing, Pinda resin remains in that part, which causes distortion during sintering. In the case of a degreased porous green body, its shape retention is poor (in other words, it has poor shape retention) If it is done, degreasing will Most of the green body is a porous body composed of powder for sintering because most of it is removed, and it is in a very fragile state by external force. The same is true for press-formed products as well, and it takes a very long time to degrease, which leads to problems such as poor productivity.

Moreover, in the method of putting powder material in a mold and pressing it at high pressure, the density is improved at the part in contact with the pressing surface, but the density decreases rapidly away from the pressing surface and the whole can be pressed uniformly. There is a problem that it can not be done (in other words, the non-uniformity of the compressed powder material causes distortion during sintering). There is a problem that this method can not produce complex shapes.

When roughing a fragile rubber press rod to a shape close to a required shape in the case of rapper press and semi-sintering, semi-sintering of this roughly processed product is shaped to allow for sintering shrinkage. In the case of machining up to a long time, it takes a long processing time, requires complicated processes, and has very poor productivity, and a large amount of material material, since cutting chips will be lost during the above processing. There is a problem that occurs. Therefore, at present, it is currently practiced mainly in special fields such as, for example, cemented carbide materials, and is not a commonly used production method.

The present invention aims to solve the fundamental problems of such a powder sintering method by developing an innovative method for thawing ice. Disclosure of the invention

The molding composition for powder sintering according to the present invention is characterized in that “a powder for sintering is supported on a pinda resin in which a solvent-insoluble resin is mixed with a solvent-soluble resin”, and further the solvent-insoluble resin is insoluble. Specifically speaking, the content of the resin is characterized by the fact that "solvent-insoluble resin is a resin that becomes fiber-like or feather-like".

Also, regarding the relationship between the sintering powder and the solvent-insoluble fibrous or reticulated resin, "the sintering powder is dispersed in the solvent-insoluble fibrous or feathered resin". It is characterized by

If it is specified with respect to the resin component that composes the pinda resin, The resin components to be formed are mutually soluble at high temperatures and are solvent-soluble at room temperature, and are characterized as being solvent-insoluble at room temperature. In terms of mixing ratio of solvent-insoluble resin and solvent-soluble resin, "solvent-insoluble resin" The volume ratio of the solvent-soluble resin and the solvent-soluble resin is 1: 0.5 to 4.0, and the mixing ratio of the pine resin and the powder for sintering is “the volume of the binder resin and the powder for sintering The ratio is 40: 60 to 65: 35 ”.

As described above, the molding composition for powder sintering of the present invention is composed of a pinda resin in which a solvent-insoluble resin is blended in a solvent-soluble resin, and a powder for sintering carried on the pinda resin. Therefore, when only the solvent-soluble resin component is degreased from an injection molded (or extrusion molded, vacuum molded or blow molded etc.) green body from this composition as a raw material, the other solvent insoluble in the degreased porous green body A resin component remains, which adheres the sintering powders to one another to be porous while exhibiting sufficient shape retention, and after degreasing, the mold of the porous green body during the sintering process. It can prevent the collapse and it becomes very easy to handle.

Moreover, in degreasing, since the one solvent-soluble resin component is uniformly mixed with the other solvent-insoluble resin component, only the soluble resin component is eluted when the solvent that dissolves the soluble resin component is eluted. The solvent-soluble resin component can be eluted almost all over the whole green body not only to the surface but also to the center part, so that the entire porous body is uniformly porous. It is possible to make it a state. The other solvent-insoluble resin component remains uniformly throughout the porous green body, and therefore does not cause distortion during sintering.

In addition, by making the solvent-insoluble resin into a fibrous or feather-like resin, the solvent-soluble resin can be uniformly dispersed in the fiber-like or feather-like resin network. There is no possibility of occurrence of coarseness and density, and even if one of the solvent-soluble resin components is degreased, the uniformity of the whole green body is not impaired. In addition, in such a pinda resin excellent in homogeneity, the powder for sintering is dispersed in a resin in which the solvent-insoluble fibrous or pellet becomes feathery, and the composition is further dispersed throughout the composition. In the green body used, coarse and dense of the sintering powder is generated throughout Also, it will be sintered with extremely high precision, and will not cause distortion during sintering.

The resin components constituting the above-mentioned pinda resin are mutually soluble in solvents at high temperatures and exhibit solvent insolubility at room temperature. Therefore, if they are kneaded at high temperature, they are uniformly mixed. As a result, the solvent-insoluble resin component is uniformly deposited, and the entire green body is mixed at a very high level of homogeneity. Although the mixing ratio of the solvent-insoluble resin and the solvent-soluble resin is 1: 0.5 to 4.0 in volume ratio, when the solvent-soluble resin is 0.5 or less with respect to the solvent-insoluble resin 1, the solvent is insoluble. There is a problem that the resin becomes excessive and degreasing takes time, and if it is 4.0 or more, there is a problem that the solvent-insoluble resin becomes too small and the retention decreases and the molded product breaks during degreasing. In addition, the mixing ratio of the binder resin and the powder for sintering is such that the volume ratio of the binder resin to the powder for sintering is 40:60 to 65:35, but 40:60 If there is more sintering powder than there is a problem that the binder resin becomes too small and the fluidity at the time of injection is poor and it is not possible to form a thin one, and if there is less sintering powder than 35. The problem is that the powder for sintering is too small and cracks occur during sintering. When the resin is 25% or less by volume ratio, the resin does not flow at the time of degreasing, and the resin does not form a shape.

The raw material composition will be described focusing on the use as a material for injection molding as described later, but of course the use as a material for injection molding, that is, if it can be used as a pellet, rod or plate The green material can be cut into a predetermined shape by machining using a green or block shape, or the raw material composition is heated and softened, and pressed into a mold to form a green body of a predetermined shape. It is also possible to form At this time, it is necessary to form the target shape in a size that allows for the amount of contraction. In such a green body, even if one solvent-soluble resin component is eluted with a solvent, the other solvent-insoluble resin component remains in the green body and this acts as an adhesive, so that green Even if the above-mentioned one of the soluble resins is eluted from the body and becomes porous, the shape retention property of the porous green body is not impaired. In addition, regarding the first method of sintering a powder for sintering using the molding composition for powder sintering, "the shrinkage during sintering with respect to the target shape using the molding composition for powder sintering" A green body is formed in anticipation of the amount, and then a soluble resin component is eluted from the green body with the solvent for elution of the soluble resin to form a porous green body, and after that, the porous green body is formed. The body is heated to burn out or burnt out the insoluble resin component remaining in the porous green body, and then the sintering powder is sintered.

The second of the sintering method of the powder for sintering using the molding composition for powder sintering “forming a rod-like, plate-like or block-like green body using the molding composition for powder sintering, This rod-like or plate-like or reticule forms a secondary green body having a size that allows for the amount of shrinkage relative to the target shape from the block-like green body, and subsequently, a soluble resin component is produced from the secondary green body. The porous green body is formed by elution with a soluble resin elution solvent to form a porous dain body, and then the porous green body is heated to burn off the insoluble resin component remaining in the porous green body or burned off. After sintering, the powder for sintering is sintered.

The third of the sintering method of the powder for sintering using the molding composition for powder sintering is described as follows. A green body of the expected size is formed, and then the soluble resin component is eluted from the durene with the solvent for elution of the soluble resin to form a porous green body, and then, the porous green body is formed. It is characterized in that the body is heated to burn off or burnt out the insoluble resin component remaining in the porous green body, and then the sintering powder is sintered.

One of the molding methods employed in the above method is "vacuum molding" and the other is "blow molding".

In addition, it is possible to use hydrogen at the time of sintering (especially at the time of thermal decomposition of pinda resin), which causes a problem especially at the time of sintering WC, and as a pinder We were able to solve the problem of using the resin in the past by “using hydrogen”. That is, when a resin is used as a binder, C generated during thermal decomposition of the resin component can be removed as CH ₄ and a precise carbon control port can be obtained. It was possible to carry out the development of a new resin binder.

This has solved all the problems that have heretofore hampered the spread of powder sintering. That is, it is not necessary to use dangerous chemicals such as nitric acid in the production process, and it is sufficient to use at least two kinds of safe and generally used resins at normal temperature, and after degreasing. The porous green body is extremely uniform and has excellent shape retention, so it is easy to handle, and in addition, it has the advantage that no distortion occurs after firing, making it applicable to all applications. In particular, it has been noted that mass production with high accuracy has become possible.

In addition, when sintering is performed in an inert atmosphere (in Ar or nitrogen), oxidation can be prevented, and a high quality sintered body can be obtained if it does not like oxidation. Also, if sintering is performed under high pressure of gas, a very dense sintered body can be obtained.

The powder-sintered member sintered by the above-described inventive method not only exhibits extremely excellent properties (shape complexity and fineness of structure) not found in the conventional sintered body, but also is cost-effective It became a thing. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail according to the illustrated embodiments. The molding composition for powder sintering of the present invention is composed of a powder for sintering and a powdery resin mainly composed of two kinds of resins composed of a uniform mixture of a solvent-soluble resin and a solvent-insoluble resin. It is The sintering powder is composed of a metal material as a main material to be sintered, an oxide, a nitride, quartz, a glass, and a pinder that combines these.

As the sintering main material that can be sintered, metal materials (stainless steel powder, Ni, W, Mo, Fe), carbides (WC, TiC, chromium carbide), nitrides (boron nitride, nitrided) Silicon, alumina nitride), oxides (quartz, alumina, glass, zirconia), etc. may be mentioned as examples, and P o, N i may be mentioned as pinders for bonding these sintering main materials. In the case of oxide (quartz, alumina, glass, zircon), it may be sintered without binder. Examples of these sintered products include cemented carbide members, cermet members, ceramic members, quartz glass members, tungsten members, stainless steel members, nickel members, molybdenum members, glass members, and composites thereof. Also, depending on the application, the average grain size of the main sintering material may be optimum. For example, in the case of a cemented carbide member, the one having an average grain size of about 0.2 to 0.5 μm is an edge (blade) It is preferable to ensure the durability of parts. A common grade has an average particle size of about 2 μm.

Pineda resin carrying these powders for sintering is mainly composed of solvent-soluble silica resin soluble in the solvent 1 and solvent insoluble silica resin insoluble in the solvent, and necessary additives such as plasticizer and mold release material. It is configured. It is more preferable that the solvent-soluble resin and the solvent-insoluble resin be completely mixed and coexist at the operating temperature, and in the present embodiment, both melt in the solvent 1 at the melting temperature (high temperature) and be uniform at the operating temperature. Resins that are mixed and separated are used.

Furthermore, in order to enhance the shape retention after degreasing and the uniform dispersion of the powder for sintering compared to the case where the solvent-soluble resin and the solvent-insoluble resin are simply mixed and mixed, the solvent insoluble resin is fibrous or feathery. It is desirable to use a resin that That is, in the case of a resin in which the solvent-insoluble resin is in the form of fibers or feathers, it dissolves completely uniformly in the solvent-soluble resin at high temperature (= melting temperature of both). When this is cooled, the solvent-insoluble resin gradually precipitates in the form of fibers, and the solvent-soluble resin and the powder for sintering become present in an entangled state between the fibers, and the solvent-soluble resin is extremely finely and uniformly. The sintering powder is in a state of being dispersed between the fibrous solvent insoluble resins.

Examples of such solvent-soluble resins are polystyrene, acrylic resin, bured chloride, cyclic polyolefin resin, polycarbonate and transition plastic. Also, examples of solvent insoluble resins include polypropylene, polyethylene, polyacetal, etc., which dissolve at high temperature (but solvent insoluble resin precipitates at room temperature). Examples of solvents include xylene, toluene, benzene, etc. There are aromatic solvents and chlorinated solvents such as dichloromethane and dichloroethane. Other plasticizers include dioctyl phthalate and dibutyl phthalate, and examples of the release agent include zinc stearate and stearic acid amide. The mixing ratio of the solvent-insoluble resin to the solvent-soluble resin is 1: 0.5 to 4.0 in volume ratio. In addition, the volume ratio of pine resin to powder for sintering is 40:60 to 65:35. As described above, powders for sintering such as the above-mentioned main sintering material and metal binder (may be a single sintering main material alone) are dispersed uniformly in a pinda resin (including a plasticizer and a releasing material) as described above. It is important to add a small amount of sintering powder to a large amount of high temperature pinda resin liquid kept at the melting temperature while stirring and uniformly disperse. When the addition of a predetermined amount of sintering powder is completed, stirring and kneading are continued while maintaining the liquid temperature to evaporate the solvent. As the solvent evaporates, the solvent-insoluble resin component gradually precipitates in the form of fibers or feathers (= micro fiber), and the solvent-soluble resin component and the sintering powder are taken in between the fibers and dispersed in ultrafine particles. As a result, the particles of the sintering powder are taken in between the fibers, and the solvent-soluble resin is dispersed and supported uniformly in the resin in the form of wrapping the surface of the resin-soluble resin, and does not aggregate.

When the stirring is continued, the viscosity of the raw material composition gradually increases with the volatilization of the solvent, and finally becomes paste or scaly. In this state, mixing is performed rather than stirring. Subsequently, the paste-like or cocoon-like viscous mixture is pelletized by means of a pellet forming machine. Of course, instead of pelletizing, it may be rod-like, plate-like or block-like depending on its use.

The pellet-like powder-sintering molding composition is prepared by ordinary injection molding (feed of raw material to an injection molding machine → heating, kneading, melting → weighing → injection of mold → pressure holding · cooling → mold opening · green body removal) It is then molded into a predetermined shape and taken out of the mold as a dullen body. In this green body, the sintering powder (= powder to be sintered + pinda) is molecularly dispersed in a binder resin mainly composed of a solvent-soluble resin component and a solvent-insoluble resin component. It is similar to a resin molded member, has excellent shape retention and is easy to handle. The green body is formed into a shape larger than the final shape (generally a similar shape to a general shape) in anticipation of the amount of shrinkage occurring in the sintering step described later.

When the green body is immersed in a solvent which dissolves one solvent-soluble resin component, the fibrous or) /, the feather-like solvent-insoluble resin component passes between the solvent-soluble resin components and gradually enters the solvent. It melts out, and the green body becomes completely porous to the core. The thin part completes degreasing of the one solute resin in a short time. The thick part takes a long time to degrease, but by taking enough time, it takes almost to the central part Completely degreasing of the solvent soluble resin component is carried out. The degreasing speed is increased by raising the solvent temperature. In addition, since it is a solvent degreasing, not only the degreasing speed is much faster than the conventional degreasing method, but also it is sufficient to simply immerse the green body in the solvent, so the equipment cost is almost unnecessary, and the degreasing obtained Products are excellent in shape retention due to the presence of solvent insoluble resin components! Handling is easy as well.

And, as described above, the solvent-insoluble resin component which does not dissolve in the solvent remains entangled with each other in the form of feathers, so the shape retention of the green body is not lost at all even in the porous state. The powder for sintering maintains a very uniform dispersion state in this fibrous solvent insoluble resin component.

Subsequently, the porous green body is placed in a firing furnace, and the temperature is raised from room temperature to 700 ° C. to heat the porous degreased product. First, the remaining solvent insoluble resin (releasing material and plastic) The thermal decomposition · disappearance of the agent), the temperature is raised further, the material is heated at the sintering temperature of the powder material, and the powder for sintering is densely integrated with each other to complete the sintering. The sintering temperature is, for example, about 750 for glass. C, C u is about 800 ° C., Ni, iron is 130 ° C. to 140 ° C., quartz is about 150 ° C., alumina silicon nitride is 160 ° C. In the case of S i C, it is 2 0 0 0 to 2 1 0 0 0 C.

Preferably, sintering in an argon atmosphere or nitrogen atmosphere can prevent oxidation of the powder for sintering, and sintering under high pressure can achieve densification of the structure. Then, it can be used as a powder-sintered member of black skin (two-a-net product) in a state of being sintered, or this powder-sintered member (n-a-net product) is further processed (for example, Polishing with a diamond tool) to make a final product. As a result, it is possible to solve all the problems that conventionally impeded the spread of powder sintering at once, mass production with high accuracy is possible for sinterable materials, and it is applied to all applications. It became possible.

In the case of firing WC, it is preferable to carry out in a hydrogen atmosphere. This is because the solvent-insoluble resin component is thermally decomposed at the time of degreasing of the solvent-insoluble resin component to form a lump of graphite in the center, particularly in the case of a thick-walled sintered body, and such defects are as if they were graphite as a defect. And it is generated in the center of the fired body, but by firing in a hydrogen atmosphere, C generated by decomposition instantaneously combines with hydrogen to become CH ₄ and leaves the fired body Because it does not form a graphite mass.

In the above case, the injection molding was mainly described. However, the method of modeling using this raw material is not limited to injection molding, and a rod-like or plate-like shape obtained by extrusion using a molding composition for powder sintering. Alternatively, a green body is formed in the shape of a block, and from this rod-like, plate-like or block-like green body, a green body having a size that allows for the amount of contraction relative to the target shape is formed. , Sinter, or pressing the molding composition for powder sintering into a mold to form a green body of a size that allows for the amount of shrinkage relative to the target shape, degrease it, and then sinter it There are various methods such as forming by conventional mold press molding, vacuum forming using the plate-like green body, and blow molding using a cylindrical green body. is there. Industrial applicability

As described above, the molding composition for powder sintering according to the present invention is a mixture of a powder for sintering, and a pinda resin mainly composed of a solvent-soluble resin and a solvent-insoluble resin. When the soluble resin component is degreased, the other solvent-insoluble resin component remains, which adheres the sintering powders to each other to exhibit sufficient shape retention and not only makes handling extremely easy. After degreasing, the porous green body can be prevented from losing its shape during the sintering process. In addition, since the solvent-insoluble resin component is in the form of fibers, it has excellent shape retention and dispersibility of the powder for sintering even when it becomes porous due to degreasing, and causes distortion during sintering. There is no The green body molded from this raw material is still easy to handle because it has good shape retention property before and after degreasing as described above.

Furthermore, by using injection molding or other methods using the above-described powder sintering molding composition, it is possible to mass-produce powder sintered members of complicated shapes in a short time, and as a mass production means, powder sintering can be performed. It is possible to fix the setting method.

Claims

The scope of the claims

1. A molding composition for powder sintering, characterized in that a powder for sintering is carried on a pine resin in which a solvent insoluble resin is mixed with the solvent soluble resin.

2. The molding composition for powder sintering according to claim 1, wherein the solvent-insoluble resin is a resin which becomes fibrous or feathery. .

3. The molding composition for powder sintering according to claim 1 or 2, wherein the powder for sintering is dispersed in a resin which becomes solvent insoluble fibrous or feathery.

4. The molding composition for powder sintering according to claim 1, wherein the solute resin constituting the binder resin is solvent soluble at high temperature and shows solvent insolubility at room temperature.

5. The sinter powder is dispersed in the resin that becomes solvent insoluble fibrous or feathery, and the solute resins that make up the noinda resin are mutually soluble in solvent at high temperature and are insoluble in solvent at room temperature. It is a combination, The molding composition for powder sintering of Claim 1 or 2 characterized by the above-mentioned.

6. The molding composition for powder sintering according to claim 1 or 2, wherein the volume ratio of the solvent-insoluble resin to the solvent-soluble resin is 1: 0.5 to 4.0.

7. The solute resin constituting the pinda resin is a combination which is solvent soluble at high temperature and shows solvent insolubility at room temperature, and the volume ratio of the solvent insoluble resin to the solvent soluble resin is 1: 0.5 to 4.0. The molding composition for powder sintering according to claim 1 or 2, characterized in that.

8. Sintering powder is dispersed in resin that becomes solvent insoluble fiber or feather. The solute resin constituting the pinda resin is a combination which exhibits solvent solubility at high temperatures and exhibits solvent insolubility at room temperature, and the volume ratio of solvent insoluble resin to solvent soluble resin is 1: 0.5 to 4 The molding composition for powder sintering according to claim 1 or 2, characterized in that 0.

A green body characterized by using a molding composition for powder sintering according to any one of claims 1 to 8 and having a size that allows for the amount of contraction relative to the target shape.

Using the molding composition for powder sintering according to any one of claims 1 to 9, a green body is formed in consideration of the amount of shrinkage at the time of sintering with respect to the target shape, and subsequently said green A soluble resin component is eluted from the lean body with the solvent for elution of the soluble resin to form a porous green body, and then the porous green body is heated to be insoluble in the porous green body. A method of sintering a sintering powder, comprising sintering the sintering powder after burning out or burning out the resin component.

A rod-like, plate-like or block-like green body is formed by using the powder sintering molding composition according to any one of claims 1 to 9, and a target shape is formed from this rod-like, plate-like or block-like green body. Then, a secondary green body having a size that allows for the amount of contraction is formed, and then the soluble resin component is eluted from the secondary green body with the solvent for elution of the soluble resin to form a porous green body. Forming, then heating the porous green body to burn out or burn out insoluble insoluble resin components remaining in the porous green body, and then sintering the sintering powder. A method of sintering a powder for sintering.

1 2. The molding composition for powder sintering according to any one of claims 1 to 9 is pressed into a mold to form a green body having a size that allows for the amount of contraction relative to the target shape, and then A soluble resin component is eluted from the green body with the solvent for elution of the soluble resin to form a porous green body, and then the porous green body is heated to form pores. A method of sintering a sintering powder comprising sintering the sintering powder after burning off or burning out the insoluble resin component remaining in the quality green body.

11. Make a plate shape the molding composition for powder sintering according to any one of claims 1 to 9, form a green body of a size that allows for the amount of shrinkage relative to the target shape by vacuum forming, and then A soluble resin component is eluted from the green body with the solvent for elution of the soluble resin to form a porous green body, and thereafter, the porous green body is heated and remains in the porous green body. A method of sintering a sintering powder, comprising sintering the sintering powder after burning off or burning away the insoluble resin component.

A cylindrical shape of the molding composition for powder sintering according to any one of claims 1 to 9 is blow molded to form a green body having a size that allows for an amount of contraction relative to the target shape, and then A soluble resin component is eluted from the green body with the solvent for elution of the soluble resin to form a porous green body, and then the porous green body is heated and remains in the porous green body. A method of sintering a sintering powder, which comprises sintering the sintering powder after burning away and / or burning off the insoluble resin component.

The method according to any one of claims 1 to 14, wherein the insoluble resin component is subjected to a hydrogen atmosphere in the thermal decomposition or sintering step or the sintering step. .

A powder-sintered member sintered by the method according to any one of claims 1 to 14.