Composition for spray formation and making method of sintering body

Abstract

A composition for spray formation and a making method of a sintering body using the composition for spray formation are provided. The composition for spray formation is characterized by comprising the following elements: magnetic metal powders with major constituent being either Fe, Ni or Co, and in particle distribution of mass basis, particle size D10 is above 2 micron and under 5 micron when accumulated mass reaches 10%, particle size D50 is above 5 micron and under 10 micron when accumulated mass reaches 50%, and particle size D90 is above 12 micron and under 28 micron when accumulated mass reaches 90%; organic binding agent comprising first resin formed by polymer containing unsaturation glycidyl and second resin with higher softening point when compared with the first resin, wherein, relative to 100 mass parts of the magnetic metal powders, the content of the organic binding agent is above 3 mass parts and under 9 mass parts.

Description

technical field [0001] The present invention relates to a composition for injection molding and a method for producing a sintered body. Background technique [0002] The powder metallurgy method of sintering a molded body containing metal powder to produce metal products has been popularized in many industrial fields in recent years because it can obtain a near-net shape sintered body. For example, since a magnetic core having a complex shape can be easily obtained by using magnetic metal powder, it can be used as a component for a magnetic actuator. [0003] There are many methods for producing a molded body (molding method), and there is known a powder injection molding method in which metal powder and an organic binder are mixed and kneaded, and the kneaded product (mixture) is spray-molded. The molded body produced by the powder injection molding method is subjected to subsequent degreasing treatment to remove the organic binder, and then fired to form a metal product o...

AI Technical Summary

Problems solved by technology

[0006] However, especially in the case of molding into a complex shape, if the shape retention of the molded body is not high enough at the time of degreasing, it is difficult to maintain the shape immediately after molding at the time of degreasing and sintering, and deformation, chipping, etc. occur to reduce the size of the sintered body precision

Especially in the injection molding method, since it is necessary to increase the ratio of the organic binder to the metal powder to improve the fluidity of the mixture, the shrinkage rate is correspondingly increased and the dimensional accuracy of the sintered body is easily reduced.

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