雰囲気制御HIP処理技術および装置技術の開発

概要

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Hot Isostatic Pressing (HIP) of ceramics has been recognized as an ideal process to produce fully dense and highly reliable parts in the course of the application to ferrite magnetic recording heads, alumina cutting tool inserts, and automobile engine parts made of silicon nitride. Usually, these parts are processed by the so-called capsule-free method in which the processed parts are directly exposed to the pressure medium gas. In this case, some interactions between the processed material and the gas may occur and this phenomenon has to be carefully considered for some nitrides and oxides. Therefore, the influence of the surrounding gas as an atmosphere is discussed from the viewpoint of thermo-dynamics. Three practical methods to create the desired atmosphere are described and some examples in the application are given for silicon nitride, superconductive ceramics and calcium carbonates. In addition the development of the HIP equipment which can create desired atmosphere will be briefly reviewed.