MAGNETIC DISK SUBSTRATE, MANUFACTURING METHOD THEREOF AND MAGNETIC DISK

• Main Authors: HATAKEYAMA HIDEYUKI, YONEMITSU MAKOTO, KITAWAKI KOTARO, SAKAMOTO RYO, OTA YUKI, TODA SADAYUKI
• Format: Patent
• Language: English; Japanese
• Published: 16.01.2020
• 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 magnetic disk substrate capable of suppressing disk flutter and having excellent grinding workability, a manufacturing method thereof, and a magnetic disk made from the magnetic disk substrate.SOLUTION: A magnetic disk substrate has a chemical composition that includes Fe of 0.005 to 0.600 mass% and Si of 0.4 mass% or less and remainder consisting of Al and inevitable foreign matter, and metal structure in which second phase particles are dispersed in Al matrix. Among the second phase particles, the number of the second phase particles having the longest diameter of 1.5 μm or more is 50000/mmor less.SELECTED DRAWING: Figure 1 【課題】ディスクフラッタを抑制でき、優れた研削加工性を有する磁気ディスク基板及びその製造方法並びにこの磁気ディスク基板から作製された磁気ディスクを提供する。【解決手段】磁気ディスク基板は、Ｆｅ：０．００５〜０．６００質量％、Ｓｉ：０．４質量％以下を含有し、残部がＡｌ及び不可避的不純物からなる化学成分と、Ａｌマトリクス中に第二相粒子が分散した金属組織と、を有している。第二相粒子のうち、１．５μｍ以上の最長径を有する第二相粒子の数が５００００個／ｍｍ2以下である。【選択図】図１