ALUMINUM ALLOY SUBSTRATE FOR MAGNETIC DISK AND MANUFACTURING METHOD THEREFOR

• Main Authors: KITAMURA NAOKI, MORITAKA YUKI, HIBINO AKIRA, KITAWAKI KOTARO, MURATA TAKUYA, OTA YUKI, TAKAHASHI HIDEKI
• Format: Patent
• Language: English; Japanese
• Published: 09.02.2017
• Subjects: ALLOYS; CASTING; CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES; 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; PERFORMING OPERATIONS; PHYSICS; POWDER METALLURGY; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PROBLEM TO BE SOLVED: To provide an aluminum alloy substrate for magnetic disk excellent in smoothness and strength of a plating surface.SOLUTION: There are provided an aluminum alloy substrate for magnetic disk consisting of an aluminum alloy containing Mg:4.5 to 10.0 mass% (hereafter %), Be:0.00001 to 0.00200%, Cu:0.003 to 0.150%, Zn:0.05 to 0.60%, Cr:0.010 to 0.300%, Si:0.060% or less, Fe:0.060% or less and the balance Al with inevitable impurities, having content of Mg-based oxide of 50 ppm or less and (I/I)×(C)≤0.1000%, where (I) is maximum emission strength of Be in a surface depth direction by a glow discharge emission spectrochemical analysis device, (I) is average emission strength of Be in a base material inside of the aluminum alloy and (C)% is Be content and a manufacturing method therefor.SELECTED DRAWING: Figure 1 【課題】めっき表面の平滑性及び強度に優れる磁気ディスク用アルミニウム合金基板を提供する。【解決手段】Ｍｇ：４．５〜１０．０ｍａｓｓ（以下、％と記す）％、Ｂｅ：０．００００１〜０．００２００％、Ｃｕ：０．００３〜０．１５０％、Ｚｎ：０．０５〜０．６０％、Ｃｒ：０．０１０〜０．３００％、Ｓｉ：０．０６０％以下、Ｆｅ：０．０６０％以下を含有し、残部Ａｌ及び不可避的不純物からなるアルミニウム合金からなり、Ｍｇ系酸化物の含有量が５０ｐｐｍ以下であり、めっき前処理を施す前において、グロー放電発光分析装置による表面深さ方向におけるＢｅの最大発光強度を（ＩＢｅ）とし、アルミニウム合金の母材内部におけるＢｅの平均発光強度を（Ｉｂｕｌｋ）とし、上記Ｂｅ含有量を（ＣＢｅ）％として、（ＩＢｅ／Ｉｂｕｌｋ）×（ＣＢｅ）≦０．１０００％であることを特徴とする磁気ディスク用アルミニウム合金基板及びその製造方法。【選択図】図１