Patent number: 5062982
Abstract: A magnetic powder for magnetic recording media, which has an average particle diameter of at most 0.1 .mu.m and is represented by the following general composition formula:(Fe).sub.a (Zr).sub.b (Si).sub.c (M.sup.1).sub.d (M.sup.2).sub.e (M.sup.3).sub.f (O).sub.gwherein M.sup.1 means at least one metal element selected from Ba, Sr, Ca and Pb, M.sup.2 denotes at least one metal element selected from Mo and W, M.sup.3 stands for at least one metal element selected from Mg, Ti, Mn, Ni, Cu, Zn, Sb, La, Al, In, Ce, Nd and Sm, a, b, c, d, e, f and g respectively represent the numbers of Fe, Zr, Si, M.sup.1, M.sup.2, M.sup.3 and O atoms, a is a number of 8.0 to 12.0, b is a number of 0.01 to 6.0, c is a number of 0.05 to 6.0, d is a number of 0.3 to 6.0, e is a number of 0.01 to 6.0, and f is a number of 0.0 to 6.0, and g is the number of oxygen atoms satisfying the atomic valences of the other elements.
Type:
Grant
Filed:
April 5, 1990
Date of Patent:
November 5, 1991
Assignee:
Nippon Zeon Co., Ltd.
Inventors:
Haruhisa Yamamoto, Hidenobu Urata, Tatsuo Kinebuchi, Hidenori Sawabe
Patent number: 5062983
Abstract: A magnetic powder for magnetic recording media, which has an average particle diameter of at most 0.08 .mu.m and a ratio of the maximum diameter to the maximum thickness of at most 8 and is represented by the following general composition formula:(Fe).sub.a (Sn).sub.b (Si).sub.c (M.sup.1).sub.d (M.sup.2).sub.e (M.sup.3).sub.f (O).sub.gwherein M.sup.1 means at least one metal element selected from Ba, Sr, Ca and Pb, M.sup.2 denotes at least one metal element selected from Cr, Y, Ce, Nd, Sm, Al, La and Cd, M.sup.3 stands for at least one metal element selected from Mg, Ti, Mn, Ni, Cu, Zn, Sb, In, Mo and W, a, b, c, d, e, f and g respectively represent the numbers of Fe, Sn, Si, M.sup.1, M.sup.2, M.sup.3 and O atoms, a is a number of 8.0 to 12.0, b is a number of 0.01 to 6.0, c is a number of 0.05 to 6.0, d is a number of 0.3 to 6.0, e is a number of 0.01 to 6.0, and f is a number of 0.0 to 6.0, and g is the number of oxygen atoms satisfying the atomic valences of the other elements.
Type:
Grant
Filed:
April 30, 1990
Date of Patent:
November 5, 1991
Assignee:
Nippon Zeon Co., Ltd.
Inventors:
Haruhisa Yamamoto, Hidenobu Urata, Tatsuo Kinebuchi, Hidenori Sawabe