Metal powder for powder metallurgy, compound, granulated powder, sintered body, and method for producing sintered body

Abstract

A metal powder for powder metallurgy includes particles each having a first region containing Fe as a principal component, a second region, in which the content of a first element is higher than in the first region, the content of Si is higher than in the first region, and the content of Fe is lower than in the first region, and a third region, in which the content of a second element is higher than in the first region, the content of Si is higher than in the first region, and the content of Fe is lower than in the first region. Further, the first region occupies 50% by volume or more of each of the particles and also is crystalline.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to Japanese Patent Application No. 2014-063428 filed on Mar. 26, 2014 and Japanese Patent Application No. 2015-005131 filed on Jan. 14, 2015. The entire disclosures of Japanese Patent Application Nos. 2014-063428 and 2015-005131 are hereby incorporated herein by reference.BACKGROUND[0002]1. Technical Field[0003]The present invention relates to a metal powder for powder metallurgy, a compound, a granulated powder, a sintered body, and a method for producing a sintered body.[0004]2. Related Art[0005]In a powder metallurgy method, a composition containing a metal powder and a binder is molded into a desired shape to obtain a molded body, and the obtained molded body is degreased and sintered, whereby a sintered body is produced. In such a process for producing a sintered body, an atomic diffusion phenomenon occurs among particles of the metal powder, and thereby the molded body is gradually densified, resulti...

AI Technical Summary

Benefits of technology

[0013]According to this configuration, when the metal powder for powder metallurgy is subjected to powder metallurgy, the second region and the third region move to a metal crystal grain boundary in a sintered body, so that the significant growth of crystal grains is prevented, and thus, a sintered body having finer crystals can be obtained. As a result, a sintered body having a high density can be obtained without performing an additional treatment.

[0035]According to this configuration, the second region and the third region contribute to the prevention of oxidation of Fe or the like without deteriorating the mechanical properties of the sintered body, respectively, and therefore, a sintered body having particularly excellent mechanical properties can be realized.

Problems solved by technology

In such a case, a sintered body is further subjected to an additional treatment such as a hot isostatic pressing treatment (HIP treatment) to increase the density, however, the workload is significantly increased, and also an increase in the cost cannot be avoided.

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