Patent ID: 6509108
Filing Date: 2003-01-21
Classification: G11B,Y10T

Abstract:
A magnetic recording disc comprising a nonmagnetic substrate having applied thereon, through a nonmagnetic underlayer, a magnetic recording layer composed of a magnetic metal material, characterized in that the nonmagnetic substrate comprises a substrate having a surface with an average surface roughness Ra of not more than 20 Ã¥, a sputtered recesses-and protrusions-forming layer having grooves with protrusions and recesses formed on the substrate by mechanical texturing in the circumferential direction, and a reinforcing coat layer having a hardness higher than that of the recesses-and protrusions-forming layer sandwiched between the substrate and the recesses-and protrusions-forming layer, the reinforcing coat layer being composed of a thin film, the reinforcing coat layer being a chromium phosphorous alloy with or without molybdenum as an additional component.