Patent ID: 6440545
Filing Date: 2002-08-27
Classification: B82Y,C01G,C01P,C09C,G11B,Y10S,Y10T

Abstract:
A powder for use in the lower layer of a magnetic recording medium, comprising acicular particles with a mean major axis length in a range of from 0.01 to 0.5 &mgr;m and a mean minor axis length in a range of from 0.01 to 0.05 &mgr;m, provided that the acicular particles are flat acicular particles which, when cut in a direction perpendicular to the major axis, exhibit a cross section having a larger width WL and a smaller width WS, wherein the ratio WL/WS is not less than 1.4, and that the quantity of discharged H2O at 100Â° C. is in a range of from 0.1 to 2.0% by weight.