| 摘要 |
PURPOSE:To obtain a substrate which has a high surface hardness and a high surface precision and is adapted for production of a magnetic thin film disc for high- density recording, by providing a titanium nitride or titanium oxide layer on an Al substrate. CONSTITUTION:A titanium nitride or titanium oxide layer is formed on the surface of an Al substrate or an Al alloy plate by the method where titanium nitride or titanium oxide is stuck to this surface directly, the method where Ti is subjected to heat treatment in an atmospheric N2 or O2 at 300-1,000 deg.C after being vapor- deposited, etc. Next, the surface of the formed layer is polished chemically by approximately 1mu to give surface smoothness to surface roughness Rmax 0.02- 0.03mu. Since this polished substrate is not magnetized even if it is subjected to heat treatment at approximately 800-1,000 deg.C, it is subjected to heat treatment at 350 deg.C or less under the state where a magnetic film is caused to adhere onto the substrate. Thus, the substrate is obtained which has a high surface precision and a high surface hardness and is adapted for a thin film disc for high-density recording. |
