MANUFACTURE OF MAGNETIC ALLOY POWDER COMPOSED PRIMARILY OF IRON OR METALLIC IRON MAGNETIC POWDER

摘要

PURPOSE:To obtain magnetic alloy powders for magnetic recording materials by a method in which iron oxide particles containing metals other than iron or needlelike iron oxide are covered with a phenolic resin and a higher fatty acid and then reduced by heating under a specific temparature and reductive condition. CONSTITUTION:Iron oxide particles containing metals other than iron or needlelike iron oxide are dispersed in water and then 0.5-5wt%, particularly 1-4wt% (based on iron oxide) a 95.5:5-5:95 mixture of a phenolic resin and a higher fatty acid is dissolved in the water and its pH is regulated to 8 or more. Then, the pH of the water is further regulated to crystallize out the phenolic resin and higher fatty acid on the surfaces of the iron oxide particles. The iron oxide particles so treated are dried and then reduced by heating under a reductive condition to meet R value 0