JP5277426B2 - Method for joining metal powder injection molded body and method for producing metal composite sintered body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of bonding metal powder injection moldings by which a plurality of metal powder injection moldings are bonded to produce a composite molding, and to provide a method of producing a metal composite sintered material having a high joining strength by sintering the composite molding. <P>SOLUTION: The metal composite sintered material is produced by: applying a paste-like coating liquid prepared by diluting metal powder of the same kind as the metal powder constituting at least one molding and a water-soluble glue-like substance with water to joint interfaces of a plurality of metal injection moldings which are preferably subjected to degreasing treatment; adhering the metal injection moldings to one another to produce thecomposite molding; and then sintering to form the metal composite sintered material. A starch glue-like substance is preferably used as the water-soluble glue-like substance. According to the invention, defective joint due to deformation of the metal injection molding can be avoided, further, the coating operation is facilitated, while the deviation of joint face or the like occurring upon the handling operation can be prevented, and high joining strength can be obtained, and, moreover, the composite sintered material having high dimension accuracy can be easily produced. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for joining metal powder injection molded bodies and a method for producing a metal composite sintered body. In particular, the present invention relates to a method for bonding molded bodies in which the molded bodies are easily bonded to each other, and to sinter the bonded molded bodies. The present invention relates to a method for producing a metal composite sintered body that is a composite sintered body having high bonding strength.

  In the fields of automobiles, precision machines, etc., many sintered products manufactured using powder injection molding technology are used as parts. Sintered products manufactured using the powder injection molding technique have advantages such as excellent product dimensional accuracy and high productivity because the near net shape can be stably secured. The manufacture of sintered metal products using powder injection molding technology usually involves blending organic binders into metal or alloy powders, mixing and kneading them into a mixed kneaded product, and injection-molding this mixed kneaded product. Then, an injection molding process to obtain a powder injection molded body having a desired shape, a degreasing process for extracting and removing the organic binder from the obtained powder injection molded body, and a powder injection molded body that has been degreased are sintered. Thus, it is carried out through a sintering step to obtain a metal sintered product having a predetermined shape. In sintered metal products using powder injection molding technology, one type of metal or alloy powder is usually used to form a molded body by one powder injection molding, and then the molded body is degreased and sintered. Thus, a sintered metal body made of a single metal or alloy is formed.

However, recently, there has been a tendency to increase the demand for sintered metal products such as complicated shapes that are difficult to form into a desired shape by a single powder injection molding and shapes made of different kinds of metals. Yes. Therefore, it is considered that a plurality of molded bodies separately injection-molded are combined to form a molded body having a desired shape and sintered to obtain a metal composite sintered body having a desired shape.
For example, when joining metal compacts using a sintering process, it is conceivable to use a solid phase diffusion method, a liquid phase diffusion method, etc. In this case, it can be said that it is preferable to apply the solid phase diffusion method from the viewpoint of dimensional accuracy. In general, the solid phase diffusion method is a method in which the cleaned surfaces of the materials to be joined are overlapped or butted together, heated to a high temperature, and joined using solid diffusion of atoms. In the liquid phase diffusion method accompanied by the generation of the liquid phase, the dimensional accuracy after bonding is lowered.

  However, when a plurality of compacts are combined and formed into a desired shape by sintering, which is a solid phase diffusion method, good bonding is achieved by separating at the joint surface or partly at the time of sintering. May not be possible. This is because, for example, when the material to be joined is a metal injection molded body, the central portion tends to be concave due to the shrinkage of the material, and the surface of the material to be joined (molded body) is not completely flat. In many cases, when overlapped, a gap is formed on the overlapped surface as shown in FIG. Furthermore, even when the surface of the material to be joined (molded body) is cleaned, micro unevenness is usually present.

  Therefore, when joining the materials to be joined by applying the solid phase diffusion method, the joining surfaces are flattened, an appropriate surface roughness of the joining surfaces is selected, and the materials to be joined are atomized. Therefore, it is necessary to select an appropriate pressure to press the bonding surface until a state in which diffusion is possible and an appropriate temperature so that atoms can diffuse at the time of bonding. For example, Non-Patent Document 1 relates to a case where iron compact is sintered, but a joining pressure of 3.28 MPa or more is necessary in order for the joining surface to have almost the same strength as the base material part. It has been shown that. In addition, the bonding temperature is desired to be as high as possible in a temperature range where no liquid phase is generated. When bonding different types of molded bodies, the bonding temperature is adjusted to the lower one of the liquid phase generation temperatures. In other materials to be bonded, the diffusion of atoms is reduced.

  For such a problem, for example, in Patent Document 1, a paste-like kneaded material made of a metal powder and an organic binder is applied to a part of the surface of a molded body produced by injection molding, and this part is used as an adhesive surface. It describes a method for producing a metal composite sintered body which is bonded to another shaped body through a paste-like kneaded layer and then degreased and sintered to form a metal composite sintered body. In the technique described in Patent Document 1, the molded body to be bonded may be degreased in advance, and the molded body to be bonded may be formed as molded bodies made of the same kind of metal powder or different metals. It is also possible to use compacts made of powder. Furthermore, in the technique described in Patent Document 1, when the metal powder used in the paste-like kneaded material is the same as the metal powder contained in the molded body or when a molded body of a different metal is bonded, It is preferable to use the same metal powder or a mixed powder of the both, and the organic binder used in the paste-like kneaded material is preferably an alcohol solution of polyvinyl alcohol (PVA). By applying the paste-like kneaded material to the bonding surfaces, even if the bonding surfaces have low flatness and are bent, bonding between the bonding surfaces becomes easy.

  In Patent Document 2, a paste-like kneaded material is applied to a portion of the surface of a molded body produced by injection molding a kneaded material of SUS420J2 or SUS316L stainless steel powder and an organic binder, and this portion is separated as an adhesive surface. After bonding through a layer of paste kneaded material and a molded body made by injection molding of different types of stainless steel powder and organic binder, degreasing, sintering, bonding, and heat treatment A metal composite sintered body made of stainless steel SUS420J2 and SUS316L produced by performing is described. In the technique described in Patent Document 2, it is preferable to use SUS420J2 stainless steel powder or SUS316L stainless steel powder and polyvinyl alcohol (PVA) dissolved in ethyl alcohol as the paste-like kneaded material to be used. Yes.

  Further, in Patent Document 3, when a plurality of molded bodies molded by an injection molding method are bonded using a compound composed of metal powder or ceramic powder and a resin component, an organic solvent is bonded to each molded body bonding surface. Alternatively, at least one of an organic solvent containing metal powder or an organic solvent containing ceramic powder is applied, and the degreasing and sintering steps are completed to join the molded body. Is described. According to the technique described in Patent Document 3, an organic solvent containing metal powder or the like is applied to the bonding surface, so that the bonding surface has substantially the same bonding strength as the base material. In the technique described in Patent Document 3, the organic solvent is preferably a mixture of dioctyl phthalate and ethanol.

JP 2004-285466 A JP 2004-315955 A Japanese Unexamined Patent Publication No. 07-11305

Hideki Kuroki, Motonobu Yokoyama: Powder and Powder Metallurgy, Vol.36 (1989) No.7, pp.813-818

  However, the techniques described in Patent Documents 1 and 2 have left problems in the paste-like kneaded material used. In the paste-like kneaded materials described in Patent Documents 1 and 2, alcohol is used as a solvent, and in the technique described in Patent Document 3, an organic solvent is used. Organic solvents such as alcohol have the advantage of high volatility and quick drying after application, but they may be dried before the bonding surfaces are overlaid, or they may dry quickly and the paste-like kneaded material can be thinly extended. There was a problem that the desired adhesive force could not be exhibited, for example, there were no cases. There is a particular problem in the case of a material to be joined having a large-area joining surface.

Moreover, in the paste-like kneaded material described in Patent Documents 1 and 2, PVA is used as the organic binder. However, when PVA is mixed with metal powder, the viscosity becomes higher, the applicability of the paste-like kneaded product is lowered, and once solidified, there is a problem that it is difficult to re-dissolve.
The present invention solves such problems of the prior art, for example, bonding metal injection molded bodies that facilitates the bonding of metal injection molded bodies whose center portions are deformed into a concave shape, etc., and can be efficiently bonded with a low bonding pressure. It aims to provide a method. Furthermore, an object of this invention is to provide the manufacturing method of a metal composite sintered compact which has the high joint strength in a joint surface.

  In order to achieve the above-mentioned object, the present inventors have intensively studied the composition of the adhesive coating solution, particularly the types of binder and solvent. As a result, it is possible to bond metal injection-molded bodies easily while suppressing the occurrence of defects. As an adhesive coating solution, water is used as a solvent, binder is used as a starchy paste, and mixed with metal powder. It was conceived that the paste was applied to the joint surface as a paste-like coating solution. By including the metal powder in the bonding coating liquid, for example, the space formed when the materials to be bonded whose center part is deformed into a concave shape can be filled, and sufficient bonding can be achieved by subsequent sintering treatment or the like. It has been found that a bonding surface having strength can be obtained and bonding defects due to deformation of the materials to be bonded can be eliminated. In addition, once pasted (cured), the starchy pasty substance as a binder can be softened again by adding water, and it is easy to adjust the viscosity by adjusting the amount of water, and to the adhesive surface. It has been found that even if the amount of water is increased to the extent that the coating operation becomes easy, the influence on the adhesive strength is small.

  In addition, by adopting starchy pasty substance as a binder and using water as a solvent, it is possible to suppress early drying due to volatilization of the solvent, etc. It was found that there was a time margin in the bonding work and the occurrence of defects was reduced. In addition, water used as a solvent also has the effect of reducing the viscosity, so that the amount of binder (starch paste) used can be reduced and the influence of residual carbon after sintering can be reduced. .

The present invention has been completed based on the above findings and further studies. That is, the gist of the present invention is as follows.
(1) When a plurality of molded bodies obtained by injection molding a kneaded product of a metal powder and a binder are applied to the bonding interface of the plurality of molded bodies and bonded to form a composite molded body, Adhesion of metal powder injection molded product, wherein the adhesive coating solution is a paste-like coating solution obtained by diluting a metal powder of the same type as the metal powder constituting the molded product and a water-soluble pasty substance with water Method.

  (2) Compound molding is performed by injection-molding a kneaded product of a metal powder and a binder and applying a solvent degreasing treatment to a bonding interface of the plurality of molded bodies by applying an adhesive coating solution. In forming a body, the adhesive coating liquid is a paste-like coating liquid obtained by diluting a metal powder of the same type as the metal powder constituting the molded body and a water-soluble pasty substance with water. Method for adhering powder injection molded body.

  (3) A compound obtained by injection-molding a kneaded product of a metal powder and a binder and applying a heat degreasing treatment to a bonding interface of the plurality of molded bodies by applying an adhesive coating solution to form a composite In forming a molded body, the adhesive coating liquid is a paste-like coating liquid obtained by diluting a metal powder and a water-soluble pasty substance of the same type as the metal powder constituting the molded body with water. Method for bonding metal powder injection molded body.

(4) In any one of (1) to (3), the adhesive coating liquid is a paste-like material obtained by diluting a metal powder of the same type as the metal powder constituting the molded body and a starchy pasty substance with water. A method for adhering a metal powder injection-molded article, which is a coating solution.
(5) In (2), the adhesive coating liquid is obtained by blending the metal powder into a mixture of the starchy paste-like substance and the water, and the metal is used in a mass% with respect to the total amount of the adhesive coating liquid. A method for adhering a metal powder injection-molded product, comprising a paste-like coating liquid containing 65 to 90% of powder, 5 to 34% of the water, and the balance being the starchy paste-like substance.

  (6) A plurality of molded bodies formed by injection molding of a kneaded product of a metal powder and a binder are coated and bonded to a bonding interface of the plurality of molded bodies to form a composite molded body. When the composite molded body is subjected to a heat degreasing process and a sintering process to obtain a metal composite sintered body, the adhesive coating solution is composed of the same metal powder and water-soluble pasty substance as the metal powder constituting the molded body. And a paste-like coating liquid diluted with water.

  (7) Composite molding is performed by injection-molding a kneaded product of metal powder and binder and applying a solvent degreasing treatment to a bonding interface of the plurality of molded bodies by applying an adhesive coating solution. In addition, when the composite molded body is further subjected to degreasing and sintering treatment to form a metal composite sintered body, the adhesive coating solution is composed of the same kind of metal powder as the metal powder constituting the molded body and water-soluble. A method for producing a metal composite sintered body, which is a paste-like coating liquid obtained by diluting a paste-like substance with water.

  (8) A composite obtained by injection-molding a kneaded product of a metal powder and a binder and further subjecting to heat degreasing treatment by applying an adhesive coating solution to the bonding interface of the plurality of molded bodies and bonding them. After forming the molded body and further subjecting the composite molded body to a sintering process to form a metal composite sintered body, the adhesive coating solution is composed of the same kind of metal powder as the metal powder constituting the molded body and water-soluble. A method for producing a metal composite sintered body, which is a paste-like coating liquid obtained by diluting a paste-like substance with water.

(9) In any one of (6) to (8), the adhesive coating solution is a paste-like material obtained by diluting a metal powder and a starchy paste-like substance of the same type as the metal powder constituting the molded body with water. A method for producing a metal composite sintered body, which is a coating solution.
(10) In (9), the adhesive coating liquid is obtained by blending the metal powder into a mixture of the starchy paste-like substance and the water, and the mass% relative to the total amount of the adhesive coating liquid, A method for producing a metal composite sintered body comprising 65 to 90% of a metal powder, 5 to 34% of the water, and the remainder being a paste-like coating liquid which is the starchy paste-like substance.

(11) The method for producing a metal composite sintered body according to any one of (6) to (10), wherein the composite molded body is formed, and then the HIP treatment is performed after the sintering treatment.
(12) In any one of (6) to (11), the plurality of compacts are compacts in which the metal powder is a powder having a tool steel composition, and the metal powder is a powder having a Ni-based alloy composition. A method for producing a metal composite sintered body characterized by being a body.

(13) The method for producing a metal composite sintered body according to (12), wherein the Ni-based alloy is Inconel 625, and the tool steel is SKD61 defined in JIS G 4404.
(14) A metal composite sintered body produced by the production method according to any one of (6) to (13).

  According to the present invention, it is easy to apply to the bonding surface, and even a metal injection molded body whose central portion is deformed into a concave shape can avoid bonding failure due to deformation of the bonding surface. There is an industrially significant effect that a metal composite sintered body capable of phase diffusion bonding and having a sufficiently high bonding strength at the bonding surface can be produced. In addition, according to the present invention, there is an effect that it becomes easy to bond different shaped metal molded bodies to each other or between molded bodies having complicated shapes that are conventionally difficult to join. In addition, according to the present invention, it is possible to prevent displacement of the joint surface during handling work such as degreasing treatment, and to improve the dimensional accuracy.

It is explanatory drawing which shows an example of a preferable manufacturing process. It is explanatory drawing which shows typically the overlapping state at the time of adhere | attaching the deformed compacts.

First, the adhesion method of the metal powder injection molded body of the present invention will be described.
In the present invention, a metal powder injection molded body (also simply referred to as a molded body) obtained by injection molding a kneaded material made of a metal powder and a binder is used as an adherend.
The molded product used in the present invention is obtained by mixing a kneaded product obtained by heating and pressurizing and mixing a metal powder and a binder and a pulverizing step of pulverizing the cooled and solidified kneaded product with an injection molding machine. It is manufactured by applying a conventional metal powder injection molding method (MIM), which is injected into a mold and cooled and solidified to obtain a metal powder injection molded body. As the metal powder to be used, any metal powder produced by a water atomization method or a gas atomization method is suitable, and these metal powders are pressure-kneaded at an appropriate temperature and time, and then cooled and ground to obtain a powder. The average particle size is more preferably 10 μm or less. Note that carbonyl powder may be used instead of water atomized powder and gas atomized powder.

As the binder to be used, any of ordinary metal powder injection molding binders can be applied, but a binder in which a wax component, a plastics component and a vegetable oil are further blended is preferable.
The wax component is a component that is mainly extracted during the degreasing process, and it is not necessary to limit the type of the wax component, but examples of preferable wax components include paraffin wax (PW) and microcrystalline wax.

Examples of the plastic component to be blended include thermoplastic resins such as polypropylene, polyethylene (PE), atactic polypropylene, and ethylene-vinyl acetate copolymer (EVA). From the viewpoints of performance and manufacturing cost.
The vegetable oil is preferably a non-drying vegetable oil. Examples of non-drying vegetable oils include peanut oil, castor oil, olive oil, and salad oil, and preferably one or more selected from them. By adding vegetable oil in addition to the above-mentioned range of wax component and plastics component, the freezing point of the binder is lowered, the fluidity of the binder is improved, and the compatibility of the binder with metal powder and plastics powder, etc. Is improved, the amount of shrinkage during cooling is reduced, the occurrence of cracks in the molded article is suppressed, and the releasability from the mold is improved.

  Next, the obtained molded body is preferably subjected to a degreasing treatment as shown in FIG. In addition, as shown in FIG.1 (b), you may give the next process (adhesion), without performing a degreasing process. As a degreasing process, any of a solvent degreasing process and a heat degreasing process may be sufficient. As shown in FIG. 1 (a), when performing solvent degreasing, a part of the binder is removed by solvent degreasing, and after bonding, the remaining part is removed by degreasing and sintering that also serves as a sintering process. It will be.

  Next, in the present invention, as described above, a plurality of molded bodies preferably subjected to degreasing treatment are superposed and bonded to form a composite molded body. It is preferable to apply and apply an adhesive coating solution to the molded body that has been subjected to the degreasing treatment because adhesion strength is easily improved due to the presence of pores. Needless to say, when stacking a plurality of molded bodies, the bonding surface is cleaned, for example, by removing foreign matter on the overlapping surface (bonding surface). After applying the adhesive coating solution to the cleaned overlapping surface (joint surface) and allowing the joint surface to be in an appropriate dry state after an appropriate amount of time, multiple molded bodies are overlapped (joint surface). Butt together and glue.

  The combination of a plurality of compacts is preferably a combination of a compact with a metal powder as a powder of a tool steel composition and a compact with a metal powder as a powder of a Ni-based alloy composition. A metal composite sintered body obtained by sintering using a composite molded body composed of this combination is suitable for applications requiring high strength and high corrosion resistance. An example of the tool steel is SKD61 defined in JIS G 4404, and an example of the Ni-based alloy is Inconel 625.

  The adhesive coating solution used in the present invention is a paste-like coating solution obtained by diluting, mixing, and kneading the metal powder constituting the molded body and the water-soluble pasty substance with water. In addition, it is preferable to mix | blend metal powder with the mixture of water and a water-soluble pasty substance, and it is set as a coating liquid. The metal powder to be used is the same kind of metal powder as the metal powder constituting the compact. In the case where the plurality of molded bodies to be bonded are molded bodies made of different kinds of metal powders, the metal powder to be used is a metal powder constituting at least one molded body among the plurality of molded bodies. In addition, it is good also as mixing of the metal powder which comprises each molded object.

  By including the same kind of metal powder as the metal powder constituting the compact in the bonding application liquid, for example, as shown in FIG. The space (gap) that can be formed when it is put together can be filled, and the subsequent diffusion of metal atoms enables sufficient diffusion of metal atoms, resulting in a bonding surface with sufficient bonding strength, resulting in deformation of the materials to be bonded Bonding failure can be eliminated.

  The adhesive coating liquid used in the present invention is mixed with a water-soluble pasty substance as a substance that exhibits adhesive strength. Here, the “water-soluble pasty substance” refers to a substance that dissolves in water and exhibits a pasty form. Thereby, water can be used as a solvent, drying time can be optimized, and there exists an advantage that an application | coating operation | work can be made easy. The water-soluble paste-like substance is not particularly limited as long as it exhibits a paste-like shape when dissolved in water and can exhibit a desired adhesive force, but is preferably a starchy paste-like substance. The starchy pasty substance is water-soluble, and once solidified, it can be softened again by adding water, and the viscosity can be easily adjusted by adjusting the amount of water, and the application to the adhesive surface is easy. Even if the amount of water is increased to such an extent, there is an advantage that there is little influence on the adhesive strength, and the operation of application and adhesion becomes easy. Here, the “starchy paste-like substance” refers to a paste-like substance formed from the starch of cereal. Examples of cereals include wheat, rice, beans, potatoes, dabioca, and the like. As for the starchy paste-like substance, there is no problem even if a commercially available starch paste is used. Moreover, PVA etc. are mentioned as water-soluble pasty substances other than a starchy pasty substance.

  The above-mentioned adhesive coating liquid is a paste-form application in which the metal powder is 65-90% and the balance is 10-35% water and starchy paste-like substance in mass% with respect to the total amount of the adhesive coating liquid. It is preferable to use a liquid. If the metal powder is less than 65%, the space (gap) generated when the compacts are overlapped with each other cannot be filled sufficiently, resulting in insufficient diffusion of metal atoms during the sintering process, ensuring the desired joint strength. become unable. On the other hand, when the metal powder is mixed in excess of 90%, the viscosity becomes high and it becomes difficult to uniformly apply the adhesive coating solution. If the mixture is less than 10%, the viscosity of the coating solution becomes too high. On the other hand, if it exceeds 35%, the gap between the metal powders is too large, and the desired bonding strength cannot be ensured.

  In addition, it is preferable that the water in the mixture of water and a starchy pasty substance is 5 to 34% by mass% with respect to the total amount of the coating solution for adhesion. When water is less than 5%, the viscosity of the coating solution is high and uniform coating becomes difficult. On the other hand, if the water content exceeds 34%, the adhesive strength is insufficient and the desired bonding strength cannot be ensured. In addition, in a mixture, it is a starchy paste-like substance except the above-mentioned water. The adhesive coating solution is preferably a paste having a viscosity of about 100 to 1000. More preferably, the adhesive coating liquid is mass% with respect to the total amount of the adhesive coating liquid, 75 to 85% of metal powder, 10 to 20% of water, and the remaining starchy paste-like substance. The material is preferably 2 to 5%.

  By using the above-mentioned adhesive coating solution and bonding to form a composite molded body, the coating operation is facilitated, and the composite molded body due to a bonding failure due to deformation of the molded body, handling work in the manufacturing process, etc. Can be prevented, and solid phase diffusion during sintering can be sufficiently performed, and the strength of the joint surface of the composite sintered body can be increased. In addition, it is preferable to perform adhesion | attachment hold | maintaining at normal temperature or appropriate temperature. Moreover, although drying is sufficient at normal temperature, there is no problem even if it is performed by heating to an appropriate temperature.

  Next, as shown in FIG. 1 (b), the composite molded body bonded in the above-described process is degreased / sintered or heated degreased and fired if it has not been degreased before bonding. As shown in FIG. 1 (a), when the degreasing treatment is performed before the bonding, the degreasing / sintering treatment is performed. When the heating degreasing processing is performed before the bonding, the sintering processing is performed. Are applied to form a metal composite sintered body.

  The solvent degreasing treatment is a method of removing the binder using an organic solvent, and the heat degreasing treatment is a method of removing the binder by thermal decomposition. In the present invention, the conditions do not need to be particularly limited. Degreasing conditions can be applied as they are. In place of the solvent degreasing process and the heat degreasing process, there is no problem as a degreasing process using supercritical carbon dioxide, which is a supercritical fluid. The degreasing treatment using supercritical carbon dioxide is a method of removing the binder using supercritical carbon dioxide, and the conditions are not particularly limited, and usual conditions can be applied as they are.

The composite molded body bonded using the coating solution for bonding used in the present invention is further subjected to sintering treatment (degreasing / sintering treatment), so that solid diffusion is sufficiently performed on the bonding surface, and strong bonding is achieved. It can be set as the metal composite sintered compact which has a surface.
The sintering process may be performed by selecting an appropriate range of sintering conditions (sintering temperature, holding time) that can ensure a predetermined sintering density according to the composition, and is not particularly limited. The sintering treatment temperature is preferably 1100 ° C. or more and 1400 ° C. or less, although it depends on the type of metal constituting the compact.

  The bonded composite molded body may be subjected to HIP treatment after the sintering treatment. By subjecting the composite molded body to HIP treatment, the density of the metal composite sintered body can be further improved, and the joint strength of the joint surface is also improved. Moreover, even if a gap exists on the joint surface after bonding, it can be eliminated.

  Water atomized SKD61 steel powder a (in mass%, 0.35% C-0.97% Si-0.40% Mn-4.93% Cr-1.21% Mo-1.01% V-balance Fe and inevitable impurities), and water atomized Inconel 625 powder b (0.02% C-0.18% Si-0.23% Mn-21.8% Cr-8.9% Mo-3.9% Nb-2.4% Fe-balance Ni and inevitable impurities were used as raw powder (metal powder). The binder was a wax component (PW), a plastic component (PE), and a vegetable oil component (peanut oil) mixed and heated and stirred, and the blending ratio was 35: 40:25.

These raw material powders (metal powders) were mixed with the binder described above and kneaded at a temperature of 130 to 140 ° C. to obtain a kneaded product for injection molding. After cooling and solidifying these kneaded materials, they are pulverized, put into an injection molding machine, set to a cylinder temperature of 120 to 130 ° C., and injected into a mold having a predetermined shape at a predetermined pressure (100 MPa) to form a cylindrical metal A powder compact (diameter 16 mmφ x length 40 mm) was used.
The obtained molded body was subjected to a degreasing treatment before bonding as shown in Table 1. Next, after the bonded surface of the molded body is cleaned with an air gun, the adhesive coating liquid shown in Table 1 is applied to the bonded surface, and after the predetermined dry state, the two molded bodies are butted together at the bonded surface. And bonded to form a composite molded body. As shown in Table 1, the two compacts to be bonded are composed of compacts composed of the same kind of metal powder as the compact composed of metal powder a, or compacts composed of metal powder a and metal powder b. It was set as the molded object comprised.

Next, the obtained composite molded body is subjected to a sintering treatment that also serves as degreasing after bonding or a sintering treatment in a reduced-pressure nitrogen atmosphere, as shown in Table 1, and solid-phase diffusion is performed on the joint surface to obtain a metal. A composite sintered body was obtained. In some cases, the sintering process was not performed when the adhesion state was poor.
The obtained metal composite sintered body was cut in a cross section perpendicular to the joining surface, polished and corroded, and the joining condition was observed with an optical microscope (magnification: 50 or 200 times). The bonding situation was evaluated by ◯ when there was no peeling and x when there was peeling. The obtained results are shown in Table 1.

  In all of the examples of the present invention, no separation at the bonding surface was observed, and sufficient solid phase diffusion was achieved, indicating that a good bonding state was obtained at the bonding surface. On the other hand, in the comparative example outside the scope of the present invention, peeling is observed, solid phase diffusion is insufficient, and it is presumed that the bonding state is poor.

Claims (14)

  When a plurality of molded bodies formed by injection molding a kneaded product of a metal powder and a binder are applied to a bonding interface of the plurality of molded bodies by applying an adhesive coating solution to form a composite molded body, the adhesive coating is applied. A method for adhering a metal powder injection molded body, wherein the liquid is a paste-like coating liquid obtained by diluting a metal powder of the same type as the metal powder constituting the molded body and a water-soluble pasty substance with water.   A composite molded body is formed by applying an adhesive coating solution to a bonding interface of a plurality of molded bodies formed by injection molding of a kneaded product of a metal powder and a binder and subjecting the solvent to a degreasing treatment. In this case, the adhesive coating solution is a paste-like coating solution obtained by diluting a metal powder of the same type as the metal powder constituting the molded body and a water-soluble paste-like substance with water. Body bonding method.   A composite molded body is obtained by injection-molding a kneaded product of a metal powder and a binder and applying a bonding coating liquid to a bonding interface of the plurality of molded bodies by applying a heat degreasing treatment to the plurality of molded bodies. In this case, the adhesive coating liquid is a paste-like coating liquid obtained by diluting a metal powder of the same type as the metal powder constituting the molded body and a water-soluble paste-like substance with water. Bonding method of molded body.   The adhesive coating solution is a paste-like coating solution obtained by diluting a metal powder of the same type as the metal powder constituting the molded body and a starchy paste-like substance with water. The method for adhering a metal powder injection molded article according to any one of the above.   The adhesive coating liquid is obtained by blending the metal powder into a mixture of the starchy paste-like substance and the water, and the metal powder is 65 to 90% by mass% with respect to the total amount of the adhesive coating liquid. The method for adhering a metal powder injection-molded article according to claim 4, wherein the paste is a paste-like coating liquid containing 5 to 34% of the water and the balance being the starchy paste-like substance.   A plurality of molded bodies formed by injection molding of a kneaded product of metal powder and binder are coated with an adhesive coating solution on the bonding interface of the plurality of molded bodies to form a composite molded body. When the body is subjected to a heat degreasing process and a sintering process to obtain a metal composite sintered body, the coating liquid for bonding uses a metal powder of the same type as the metal powder constituting the molded body and a water-soluble pasty substance as water. A method for producing a metal composite sintered body, which is a paste-like coating liquid diluted with 1.   A composite molded body is obtained by injection-molding a kneaded product of a metal powder and a binder and subjecting a plurality of molded bodies to solvent degreasing treatment by applying an adhesive coating solution to the bonding interface of the plurality of molded bodies and bonding them. Thereafter, when the composite molded body is further subjected to degreasing and sintering treatment to obtain a metal composite sintered body, the adhesive coating solution is composed of the same metal powder as the metal powder constituting the molded body and a water-soluble pasty substance. And a paste-like coating liquid diluted with water.   A composite molded body is formed by injection-molding a kneaded product of a metal powder and a binder, and further applying a heat degreasing treatment to a bonding interface by applying an adhesive coating solution to a bonding interface of the plurality of molded bodies. After that, when the composite molded body is further subjected to a sintering treatment to form a metal composite sintered body, the adhesive coating solution contains the same metal powder and water-soluble pasty substance as the metal powder constituting the molded body. And a paste-like coating liquid diluted with water.   9. The adhesive coating solution according to claim 6, wherein the adhesive is a paste-like coating solution obtained by diluting a metal powder of the same type as the metal powder constituting the molded body and a starchy paste-like substance with water. The manufacturing method of the metal composite sintered compact in any one.   The adhesive coating solution is obtained by blending the metal powder into a mixture of the starchy paste-like substance and water, and the metal powder is 65 to 90% by mass% with respect to the total amount of the adhesive coating solution. 10. The method for producing a metal composite sintered body according to claim 9, wherein the metal composite sintered body according to claim 9 is a paste-like coating liquid containing 5 to 34% of the water and the balance being the starchy paste-like substance.   The method for producing a metal composite sintered body according to any one of claims 6 to 10, wherein after the composite molded body is formed, an HIP process is performed after the sintering process.   The plurality of molded bodies are a molded body in which the metal powder is a powder having a tool steel composition and a molded body in which the metal powder is a powder having a Ni-based alloy composition. A method for producing a metal composite sintered body according to claim 1.   The method for producing a metal composite sintered body according to claim 12, wherein the Ni-based alloy is Inconel 625, and the tool steel is SKD61 defined in JIS G 4404.   A metal composite sintered body produced by the production method according to claim 6.

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