FERROMAGNETIC POWDER AND ITS PREPARATION

摘要

PURPOSE:To obtain ferromagnetic powder with superior magnetic characteristics by sticking the surface of needle grains whose main component is iron oxyhydroxide or iron oxide with aluminum compounds and applying heat reduction to said grains. CONSTITUTION:Aluminum compounds such as aluminum hydroxide which is obtained by neutralizing aluminum sulfate are stuck with suitable thickness on the surface of needle grains whose main component is iron oxyhydroxide such as alpha- FeOOH or iron oxide such as alpha-Fe2O3 and grains whose surface is stuck with aluminum compounds are reduced while heating by the fixed procedure to obtain ferromagnetic powder with superior magnetic characteristics which consists of metallic iron mainly and whose surface is stuck with aluminum components mainly as aluminum oxide.