| 摘要 |
PURPOSE:To obtain the above-mentioned powder having excellent oxidation resistance and dispersibility by subjecting magnetic metallic powder (powder) to an annealing treatment in an inert gaseous atmosphere contg. a slight amt. of oxygen then to a surface treatment with an org. sulfur compd. CONSTITUTION:The powder obtd. by reducing iron oxyhydroxide or iron oxide is subjected to the annealing treatment in the inert gas contg. preferably about 50-10,000ppm oxygen and is then subjected to the surface treatment with the org. sulfur compd. generally by a wet process. More specifically, the above- mentioned powder is dipped into a solvent for a magnetic paint such as benzene dissolved or dispersed therein with the org. sulfur compd. and is then dried. Preferably, O,O'-dibenzamide diphenyl disulfide or the mercaptan compd. expressed by the formula: R-SH or the like is particularly preferable as the org. sulfur compd. R in the formula denotes an alkyl group, phenyl group, cyclohexyl group, allyl group or benzyl group of 4-20C. |
