NONMAGNETIC PARTICLE POWDER FOR NONMAGNETIC UNDERLAYER OF MAGNETIC RECORDING MEDIUM, AND MAGNETIC RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide nonmagnetic particle powder for a nonmagnetic underlayer of a magnetic recording medium, which is excellent in dispersibility in a coating for the nonmagnetic underlayer and in a filling property in the nonmagnetic underlayer. SOLUTION: The nonmagnetic particle powder includes hematite particle powder of which the average long axis diameter is 30 nm or less, the axial ratio (a ratio of a long axis diameter to a short axis diameter) is 2.0 or more, and the tap density (ρt) is 0.60 g/cm3or more. The magnetic recording medium uses the nonmagnetic particle powder as the nonmagnetic particle powder for the nonmagnetic underlayer of the magnetic recording medium. COPYRIGHT: (C)2011,JPO&INPIT