Production of magnetic metallic powder keeping stability

Abstract

Abstract PURPOSE:To produce magnetic metallic powder having excellent corrosion resistance and stability by dipping the magnetic metallic powder into an org. solvent contg. an oxidation inhibitor then oxidizing forcibly said powder in an inert gas contg. a small amt. of oxygen. CONSTITUTION:The powder of pure iron and iron alloy obtd. by subjecting hematite or hematite contg. at least one kind among Ni, Co, Mn, Mg, Cu, Sn, Ti, Bi, Al, Cr and Si to hydrogen reduction has large surface activity and is quickly oxidized in air, by which the excellent magnetic characteristic thereof is lost and therefore said powder is subjected to a surface treatment. The above- mentioned pure iron or alloy iron powder is dipped into an org. solvent such as toluene or the like contg. an oxidation inhibitor such as cresol, phenol or the like. The powder is then heated for >=1 hour at <=600 deg.C in an inert gas such as He, Ar or the like contg. 1-8% oxygen to form a uniform and dense oxide film on the powder surface of the pure iron, etc. thereby preventing the surface against the additional oxidation and stabilizing the surface. The powder metal having the excellent magnetic characteristic is produced.

Inventors

• 👤 Tetsushi Yamamoto
• 👤 哲史 山本
• 👤 Takayoshi Yoshizaki
• 👤 吉崎　孝嘉

Bibliographic Details