Permanent magnet having improved corrosion resistance and manufacture thereof

TLDR: In this article, the authors proposed to improve corrosion resistance, prevent magnetic property from deteriorating, and reduce the cost by setting oxygen among the constituents of a magnet to 0.6-0.6wt.

Abstract: PURPOSE: To improve corrosion resistance, prevent magnetic property from deteriorating, and reduce the cost, by setting oxygen among the constituents of a magnet to 0.6wt.% or higher, carbon to 0.05-0.15wt.%, and nitrogen to a maximum of 0.15wt.% or higher. CONSTITUTION: The ingot cast is made by a vacuum induction melting an alloy material and is further turned into powder. The inclusion of oxygen in the alloy is achieved by controlling air of a jet mill, and powder is mixed in air. Nitrogen is similarly added by the jet mill. Carbon is added during melting. An alloy powder is subjected to cold isostatic compression for forming a cold compression molding, and the molding is baked in a vacuum oven, thus improving stability at high temperature and high humidity and improving corrosion resistance, reducing the deterioration of a magnetic property, and manufacturing a permanent magnetic easily.