| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic recording medium excellent in heat resistance and mechanical strength. SOLUTION: The magnetic recording medium consists of spherical silica which is spherical and has 0.01 to 1μm average particle diameter, <=1.5 geometric standard deviationσin the distribution of grain size expressed by formula ofσ=(D1/D2)0.5, wherein D1 is the particle diameter at 84 cumulative wt.% and D2 is the particle diameter at 16 cumulative wt.%, and has >=6μmol/g silanol groups.
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