Magnetic coating composition and magnetic recording medium
AssigneeDaikin Industries, Ltd.
InventorsYoshiyuki Shibuya, Shigeo Daimon, Kazuo Okamura
Life of this patent
Estimating the term…
Abstract
A magnetic coating composition comprising acicular particles containing iron carbide and a main magnetic material.
Claims11
A magnetic coating composition comprising a main magnetic material selected from the group consisting of magnetic iron oxide particles, cobalt-modified iron oxide particles, chromium dioxide particles and metallic iron particles, and acicular particles containing iron carbide produced by contacting acicular particles of iron oxyhydroxide or iron oxide with carbon monoxide or with a mixture of carbon monoxide and hydrogen, said acicular particles being up to 2 .mu.m in average particles size (long axis or length) and having an average axial ratio of from about 3 to about 20 of primary particles.
In a magnetic recording medium comprising a substrate coated with a magnetic coating composition having magnetic particles dispersed in a binder, the improvement wherein the magnetic powder is a mixture of (a) magnetic metal particles, and (b) magnetic iron carbide particles and/or magnetic particles containing iron oxide and iron carbide with the weigh ratio of (a) to (b) being in the range between 99.5:0.5 and 80:20.
Dependencies are inferred from the claim text.