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

Abstract

A metal powder comprising particles, which contain Fe, Cr, Si and C, and in which when one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as a first element, and one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta, and having a higher group number in the periodic table than that of the first element or having the same group number in the periodic table as that of the first element and a higher period number in the periodic table than that of the first element is defined as a second element, the first element is contained in a proportion of 0.01% by mass or more and 0.5% by mass or less, and the second element is contained in a proportion of 0.01% by mass or more and 0.5% by mass or less.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to Japanese Patent Application No. 2015-023385 filed on Feb. 9, 2015. The entire disclosures of Japanese Patent Application No. 2015-023385 is 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, and 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, whereby the molded body is gradually densified, resulting in sintering.[0006]For example, JP-A-2012-87416 proposes a metal powder for powder metallurgy which contains Zr and Si, with the re...

AI Technical Summary

Benefits of technology

This patent is about a new type of metal powder for powder metallurgy that has a small amount of a passivation film made of Cr oxide. This passivation film helps to improve the sinterability of the metal powder particles, resulting in higher density and excellent mechanical properties of the sintered body without needing any additional treatments. The metal powder also has silicon segregated on its surface, which acts as a deoxidizing element to prevent the oxidation of iron or chromium, and this results in reduced generation of oxides and improved sinterability. Additionally, the ratio of silicon dioxide can be optimized to enhance the sinterability while reducing excessive formation of the passivation film. Overall, this patent provides a technical solution for producing high-quality sintered bodies with improved properties.

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 is inevitable.

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