Stock material or miscellaneous articles – Circular sheet or circular blank – Recording medium or carrier
Patent
1988-08-03
1991-04-09
Thibodeau, Paul J.
Stock material or miscellaneous articles
Circular sheet or circular blank
Recording medium or carrier
428 65, 428611, 428678, 428694, 428900, G11B 2300
Patent
active
050063880
ABSTRACT:
Disclosed are magnetic discs having (A) a Cr-layer, as a lower layer, which has a composition comprising (1) substantially Cr or (2) 10% by weight or less of one or more selected from Cu, Nb, Ti, V, Zr, Mo, Zn, W and Ta, and a balance of being substantially Cr, and (B) a magnetic recording medium layer, as an upper layer, which has a composition comprising (1) substantially Co, (2) 30% by weight or less of Ni and a balance of being substantially Co, (3) 10% by weight or less of one or more selected from Y, La, Ce, Pr, Nd, Sm, Gd, Tb and Dy, and a balance of being substantially Co, (4) 30% by weight or less of Ni, 10% by weight or less of one or more selected from Y, La, Ce, Pr, Nd, Sm, Gd, Tb and Dy, and a balance of being substantially Co, (5) 10% by weight or less of one or more selected from Cu, Nb, Ti, V, Cr, Zr, Mo, Zn, W and Ta, and a balance of being substantially Co, (6) 30% by weight or less of Ni, 10% by weight or less of one or more selected from Cu, Nb, Ti, V, Cr, Zr, Mo, Zn, W and Ta, and a balance of being substantially Co, (7) 10% by weight or less of one or more selected from Y, La, Ce, Pr, Nd, Sm, Gd, Tb and Dy, 10% by weight or less of one or more selected from Cu, Nb, Ti, V, Cr, Zr, Mo, Zn, W and Ta, and a balance of being substantially Co, or (8) 30% by weight or less of Ni, 10% by weight or less of one or more selected from Y, La, Ce, Pr, Nd, Sm, Gd, Tb and Dy, 10% by weight or less of one or more selected from Cu, Nb, Ti, V, Cr, Zr, Mo, Zn, W and Ta, and a balance of being substantially Co, both as formed on a non-magnetic substrate, except those where the lower layer has the composition (1) and the upper layer has the composition (1) or (2) as well as those where the lower layer has the composition (1) and the upper layer has the composition (5) or (6) containing only one or more of Cr, Ta and/or W. The magnetic discs have noticeably improved magnetic characteristics and/or corrosion-resistance.
REFERENCES:
patent: 3150939 (1964-09-01), Wenner et al.
patent: 4226681 (1980-10-01), Shirahata et al.
patent: 4552820 (1985-11-01), Lin et al.
patent: 4631202 (1986-12-01), Opfer et al.
Kawamoto Atsushi
Kuzuo Ryuichi
Ohmori Kenji
Sekiya Hiroko
Tada Junya
Sumitomo Metal Mining Company Limited
Thibodeau Paul J.
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