| 摘要 |
A substrate suitable for a magnetic recording comprises a glass having protrusions on its surface, wherein the protrusions have a height of 50 to 1000 ANGSTROM and a width of 0.01 to 1 mu m, the density of protrusions on the substrate is from 10 to 1000 per 100 mu m<2>, the area ratio of the protrusions is from 0.1 to 50%, and the ratio of peak height of the protrusions on a mean line (Rp) to maximum height (Rmax) with respect to surface roughness of the substrate is at least 60%. The protrusions are formed by chemical etching with an aqueous solution comprising hydrofluoric acid at a concentration of 0.15 to 0.9 N and potassium fluoride at a concentration of 2 to 6 N, the temperature of the solution being 5 to 20 DEG C. The substrate, when coated with an undercoat film, a magnetic film and a protective film provides a recording disc in which the frictional forces and the sticking forces between the disc and a head are reduced. |
