MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To obtain a magnetic tape having a high S/N ratio and excellent runnability of high output by incorporating magnetic metallic powder having a specific BET value or above, nonmagnetic powder having a specific number average grain size or below and specific Mohs' hardness or above and further anionic surface active agent into a magnetic layer. CONSTITUTION:The magnetic metallic powder having >=40m<2>/g BET value, the nonmagnetic powder having <=0.35mum average grain size and >=5Mohs' hardness and the anionic surface active agent are incorporated into the magnetic layer. The raw material for the magnetic powder to be used is exemplified by an alloy such as Fe-Ni-Co and is preferably the magnetic powder having >=80atom% iron. A differential temp. changes does not arise preferably up to 80 deg.. The dispersibility is considerably deteriorated and the decreases in the S/N ratio and output is liable to be resulted if the BET value of the magnetic metallic powder is >=40m<2>/g but such can be averted by using the anionic surface active agent. Org. powder, inorg. powder or the mixture composed thereof is used as the nonmagnetic power having <=0.35mum number average grain size and >=5Mohs' hardness.