Magnetic recording coating

Abstract

A magnetic recording medium, such as a magnetic recording disk, having a magnetic recording layer that contains ferromagnetic and nonferromagnetic particles dispersed in a binder. The nonferromagnetic particles are disposed in the binder to be substantially equal to the thickness of the coated layer, and are of a material having a greater hardness than that of the binder.

Thus, what is claimed is: 
     
       1. A magnetic recording medium compising ferromagnetic and alumina particles dispersed in a binder as a unitary coating upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying non-magnetic substrate and present in an amount not above 5% by weight of the ferromagnetic and alumina particles. 
     
     
       2. A magnetic recording medium comprising ferromagnetic and alumina particles dispersed in a binder as a unitary coating upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying non-magnetic substrate and present in an amount between 3 to 5% by weight of the ferromagnetic and alumina particles. 
     
     
       3. A magnetic recording medium comprising ferromagnetic and alumina particles dispersed in a binder as a unitary coating of substantially 50 microinches upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying nonmagnetic substrate and present in an amount not above 5% by weight of the ferromagnetic and alumina particles. 
     
     
       4. A magnetic recording medium comprising ferromagnetic and alumina particles dispersed in a binder as a unitary coating of substantially 50 microinches upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying non-magnetic substrate and present in an amount between 3 to 5% by weight of the ferromagnetic and alumina particles.