US 5,314,745 A · Magnetic recording medium having a glass substrate, heat retaining non magnetic metal layer formed over the substrate, amorphous nip layer, Cr layer and magnetic layer

Abstract

A magnetic recording medium comprising a substrate, a ground layer formed over at least one surface of the substrate, and a magnetic layer formed over the ground layer, the ground layer being formed of a material containing at least 95% by weight of Cr. The substrate comprises a base of glass plate, a nonmagnetic metal layer formed over at least one surface of the base, and an amorphous NiP layer formed over the nonmagnetic metal layer. The nonmagnetic metal layer is formed of a material containing at least 95% by weight of Cr, or a material containing at least 95% by weight of Ti or a material containing at least 95% by weight of Cr-Ti alloy. The recording medium has excellent flatness and a high coercive force.

Claims6

Dependent claims

A magnetic recording medium comprising a substrate, a ground layer made of a material containing at least 95% by weight of Cr and formed over one surface of the substrate, and a magnetic layer formed over the ground layer;

said substrate comprising:
a base of glass plate;
a nonmagnetic metal layer formed over the glass base and having a thickness sufficient for retention of heat wherein the substrate is heated by infrared electromagnetic waves for forming the ground layer;
and
an amorphous NiP layer formed over the nonmagnetic metal layer and having a thickness of about 250 to 1000 angstroms.

2 more elements

Dependencies are inferred from the claim text.

Magnetic recording medium having a glass substrate, heat retaining non magnetic metal layer formed over the substrate, amorphous nip layer, Cr layer and magnetic layer

Life of this patent

Magnetic recording medium having a glass substrate, heat retaining non magnetic metal layer formed over the substrate, amorphous nip layer, Cr layer and magnetic layer

Life of this patent

Abstract

Claims6