STABILIZATION OF FERROMAGNETIC METAL POWDER

PURPOSE:To obtain highly stable ferromagnetic metal powder by immersing ferromagnetic metal powder in organic solvent dissolving organic metal compound, forming metal hydrate by hydrolysis of such organic metal compound, depositing metal hydrate on the ferromagnetic metal particle surface and thereafter conducting heat treatment. CONSTITUTION:An organic metal compound, which dissolves to an ordinary organic solvent not easily binding with ferromagnetic metal powder such as toluene, heptane, easily subjected to hydrolysis and generates very stable hydrate with such hydrolysis, can be used. As a metal generating such hydrate explained above, an organic metal compound of the metal such as Al, Si, B, Ti, Zn and Zr may be used. As the material, which shows solubility and is easily subjected to hydrolysis and allows hydrate obtained to change to an oxide with the heat processing, for example, metal alkoxide compound, metal alkyl compound are preferable. the heat treatment must be conducted in an inactive gas atmosphere, in hydrogen gas, or in a reducing gas atmosphere mainly composed of hydrogen.