MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To obtain the excellent transfer property as well as to reduce the electrification property by using together both the Co-coated iron oxide magnetic powder and the Co solid solution type iron oxide magnetic powder. CONSTITUTION:The gamma-Fe2O3 powder is dispersed into the aqueous solution the Co salt, the ferrous iron and the equivalent alkali and then treated at the temperature lower than the boiling point to form the iron oxide layer containing mainly Co and ferrous iron on the iron oxide magnetic powder. On the other hand, the goethite with the Co ion adsorbed on the surface undergoes the heat treatment to give the solid solution to Co into the crystal grid. Then the mixture magnetic powder composed of 60-90 parts by weight of the Co-coated iron oxide magnetic powder and 10-40 parts by weight of the Co solid solution type magnetic powder is coated on the substrate along with the bonding agent.