MAGNETIC RECORDING MEDIA PREPARED FROM MAGNETIC PARTICLES HAVING AN EXTREMELY THIN, CONTINUOUS, AMORPHOUS, ALUMINUM HYDROUS OXIDE COATING

摘要

according to one aspect, the present invention relates to a process for preparing the coated magnetic particles. according to this method, an aqueous soil colloidal particles hydrolyzed and amorphous state is mixed with an aqueous suspension containing magnetic particles.the colloidal particles are amorphous, hydrolyzed, and state an average size between 0.5 and 5 nm and an average degree of hydrolysis of between 1.5 and 3.during mixing, the colloidal particles to form an amorphous layer and aqueous aluminum oxide layer on the magnetic particles, with an average thickness of from 0.5 to 5 nm. the present invention also describes the coated magnetic particles.these include a magnetisable core and a continuous layer and amorphous aluminum oxide formed in the aqueous core. the layer has a thickness between 0.5 and 5 nm. according to a variant, the present invention relates to a magnetic recording medium comprising a magnetic layer formed on a non magnetisable material.the magnetic layer includes magnetic particles coated with the above dispersed in a polymeric binder.