Improvement of tribological properties of magnetic tape by silica coating onto the Co-gamma-Fe2O3 fine particles

In order to improve the tribological properties of magnetic tape with Co-ga mma-Fe2O3 fine particles against a magnetic head, the silica coating onto t he surface of Co-gamma-Fe2O3 particles in aqueous slurry is investigated ex perimentally, and the kinetic friction coefficient of magnetic tapes prepar ed using the coated particles is measured. By this silica coating, the amou nt of myristic acid absorbed on the Co-gamma-Fe2O3 particles tends to decre ase and the kinetic friction coefficient of the magnetic tapes can be reduc ed from 0.4 to 0.2 because of the increase of the effective amount of myris tic acid working as the lubricant when the magnetic tape is moving. Since t he magnetic properties and the dispersibility of Co-gamma-Fe2O3 pigment in the magnetic lacquer are not degraded by the silica coating, this coating m ethod is expected to result in magnetic recording media with both good magn etic and low friction properties.