| 摘要 |
PROBLEM TO BE SOLVED: To obtain good adhesiveness and to improve wear resistance by allowing the hydrogen contained in the thin film protective layer on a disk to exist at the lowest atomic % at the part nearest the base material, to gradually increase toward the surface and to exist at the highest atomic % on the surface. SOLUTION: A single layer over-coating 15 has a hydrogenation concn. gradient increasing toward the film surface. The hydrogenation gradient starts from about 25atm.% at the lowermost surface of the film in contact with the magnetic material of the disk. The hydrogenation level in the over-coating 15 increases in the film and is about 35 to 40atm.% at the outside surface of the film. The hydrogen content of about 8atm.% at the lowest level of the film in contact with the magnetic material is the actual threshold and 20 to 30atm.% is practical in production environment. The peeling of the film increases dramatically when the hydrogen content exceeds 35%. The hardness is higher at 20 to 35atm.% than at 10atm.% or 40atm.% of the hydrogen. The practical upper limit of the hydrogenation % is considered to be near 40atm.%. |
