Fe-Si TYPE IRON-BASED SOFT MAGNETIC POWDER COATED WITH OXIDE DEPOSIT FILM AND PROCESS FOR PRODUCING THE SAME

摘要

An Fe-Si-type iron-based soft magnetic powder coated with an oxide deposit film which comprises Fe-Si type iron-based soft magnetic particles and, formed on the surface of each particle, an oxide deposit film comprising Mg, Si, Fe, and O. In the oxide deposit film comprising Mg, Si, Fe, and O, the contents of magnesium and oxygen increase toward the surface and the content of iron decreases toward the surface. The oxide deposit film has a silicon concentration gradient in which the content of silicon in a layer around the outermost surface increases toward the outermost surface. The coated magnetic powder contains metallic iron in the base and has a fine crystal structure having an average crystal grain diameter of 200 nm or smaller.