| 摘要 |
PURPOSE:To improve oxidation stability by precipitating and sticking one or more among Co, Ni and Cr on the surface of Fe-based oxyhydroxide or oxide in an org. solvent with an aq. NH3 soln., and reducing the oxyhydroxide or oxide as starting material under heating. CONSTITUTION:Fe-based oxyhydroxide or oxide having about 40-120m<2>/g specific surface area is dispersed in 1-6C alcohol such as isopropanol as a solvent and an aq. NH3 soln. is added to keep pH8-9.5. A soln. prepd. by dissolving the nitrates, chlorides or acetates of one or more among Co, Ni and Cr in alcohol and an aq. NH3 soln. are then simultaneously dropped while keeping pH8-9.5 and one or more among Co, Ni and Cr are stuck on the surface of the oxyhydroxide or oxide by <=0.50mol per 1mol Fe. This oxyhydroxide or oxide is calcined as starting material in a reduction atmosphere and reduced under heating to about 300-600 deg.C in a flow of gaseous H2 to obtain ferromagnetic metal powder having oxidation stability. |
