Magnetic recording medium
AssigneeVerbatim Corporation
InventorMamoru Kido
Life of this patent
Estimating the term…
Abstract
The present invention provides a magnetic recording medium having excellent durability under severe environment. The magnetic recording medium is provided with a flexible non-magnetic support, and a magnetic layer which is provided thereon and contains ferromagnetic powder and bonding agent. Vickers hardness Hv of the magnetic layer up to a certain indentation depth of an indentator is 12-20.
Claims4
A magnetic recording medium having a flexible non-magnetic support, and a magnetic layer containing ferromagnetic powder and bonding agent characterized in that Vickers hardness Hv of the magnetic layer is 12-20 gf/.mu.m.sup.2,
- wherein the Vickers hardness Hv (gf/.mu.m.sup.2) is defined as:
- Hv=1082.7.times..DELTA.P/.DELTA.d.sup.2,
- where .DELTA.P/.DELTA.d.sup.2 is a slope of P versus d.sup.2 curve, the curve is approximate to two straight lines of different slopes with an inflection point, where P (gf) is a load added to a diamond trigonal pyramid indentator with an angle of 80.degree. between edges at vertex when the indentator is pressed to the magnetic layer at a rate of 10.5 nm/sec, and where d (.mu.m) is an indentation depth of the indentator into the magnetic layer, the value of d is smaller than the value of d at the inflection point.
A method of manufacturing a magnetic recording medium having a flexible non-magnetic support, and a magnetic layer containing ferromagnetic powder and bonding agent characterized in that the magnetic recording medium is manufactured in a manner that Vickers hardness of the magnetic layer is 12-20 gf/.mu.m.sup.2,
- wherein the Vickers hardness Hv (gf/.mu.m.sup.2) is defined as:
- Hv=1082.7.times..DELTA.P/.DELTA.d.sup.2,
- where .DELTA.P/.DELTA.d.sup.2 is a slope of P versus d.sup.2 curve, the curve is approximate to two straight lines of different slopes with an inflection point, where P (gf) is a load added to a diamond trigonal pyramid indentator with an angle of 80.degree. between edges at vertex when the indentator is pressed to the magnetic layer at a rate of 10.5 nm/sec, and where d (.mu.m) is an indentation depth of the indentator into the magnetic layer, the value of d is smaller than the value of d at the inflection point.
Dependencies are inferred from the claim text.