Magnetic powder is a very important raw material for powder magnetic cores. Most of the powder is iron-based alloy, and doesn’t have high corrosion resistance. Also, it is required to form insulation films on the powder to reduce core loss. We have developed a wet process to form a silica-based film with excellent corrosion reasistance and insulation performance.
It is possible to form the silica-based coating uniformly with thickness below 100 nm. Besides, the thickness can be controlled easily. With 10 nm-thickness, corrosion-resistance and insulation performance of magnetic powder can be significantly improved.