SUBSTRATE FOR MAGNETIC DISK, METHOD FOR MANUFACTURING THE SAME, AND MAGNETIC DISK USING SUBSTRATE FOR MAGNETIC DISK

• Main Authors: IMAGAWA KIMIE, HATAKEYAMA HIDEYUKI, YONEMITSU MAKOTO, KITAWAKI KOTARO, NAKAMURA TADAHIRO, NAKAYAMA MASARU
• Format: Patent
• Language: English; Japanese
• Published: 19.09.2019
• Subjects: ALLOYS; CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS ANDNON-FERROUS ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; METALLURGY; PHYSICS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

To provide a substrate for a magnetic disk having a stable fluttering characteristic, and a method for manufacturing the substrate.SOLUTION: The substrate for a magnetic disk according to the present invention is characterized in that the flatness is 30 μm or less and the difference in the flatness between before and after heating processing is performed at 190°C for 20 hours is 20 μm or less. The substrate for a magnetic disk can be manufactured by performing heating processing on the substrate for a magnetic disk after polishing at temperatures of 100°C to 250°C within 72 hours after the last polishing step, which is performed at least one time, is performed.SELECTED DRAWING: Figure 1 【課題】安定したフラッタリング特性を有する磁気ディスク用基板とその製造方法を提供する。【解決手段】本発明に係る磁気ディスク用基板は、平坦度が３０μｍ以下であり、１９０℃×２０ｈの加熱処理をした前後の平坦度の差が２０μｍ以下となることを特徴とする。この磁気ディスク用基板は、少なくとも１回行われる研磨工程の最後の研磨後７２ｈ以内に、研磨後の磁気ディスク用基板を１００〜２５０℃で加熱処理することで製造することができる。【選択図】図１