| 摘要 |
<p>Powder for sublayer of coating type magnetic recording medium, comprising flat acicular iron oxide particles of 20 to 200 nm average major axis length, wherein a minor axis cross section made in the direction perpendicular to the major axis has a long width and a short width, the minor axis cross section ratio of long width to short width being larger than 1.3 substantially uniformly in the direction of major axis, which powder exhibits a specific surface area, measured by the BET method, of 30 to 100 m2/g. Preferably, this sublayer powder contains P in an amount of 0.1 to 5.0 wt.% and further contains R (at least one member of rare earth elements including Y) in an amount, in terms of R/Fe atomic ratio percent (at.%), of 0.1 to 10 at.%.</p> |
