INSULATED IRON-BASE POWDER FOR SOFT MAGNETIC APPLICATIONS

摘要

The present invention relates to ferromagnetic powders with an electrically insulating layer on iron particles intended for the manufacture of components having improved soft magnetic properties at low and medium frequencies. The invention comprises an iron powder coated with a dielectric insulating layer comprising boron bearing compounds to form an insulated ferromagnetic powder. The present invention also relates to a method of making these insulated ferromagnetic powders. The present invention further relates to a method of synthesizing a product made from insulated ferromagnetic powders via a post-heat treatment at a moderate temperature (300° C. to 700° C.), to form a glass-like coating which acts as an electrical insulator. A preferred embodiment of the present invention is obtained when small amounts of alkali bearing compounds are added to the precursors to modify the coating chemistry and significantly increase the electrical resistivity after heat treatment.