MAGNETIC RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To sufficiently improve corrosion resistance by specifying the pH of a magnetic recording medium mainly contain MnBi magnetic powder in a magnetic layer to alkalinity of a specific value or above. SOLUTION: The pH of the magnetic recording medium mainly contg. the MnBi magnetic powder in the magnetic layer is specified to the alkalinity of >=7. If the pH in the system of the magnetic recording medium is made alkaline of >=7 in such a manner, a passive phase of an Mn system is formed on the surface of the MnBi magnetic powder and the corrosion resistance of the MnBi magnetic powder is improved. The magnetic recording medium having the corrosion resistance of a practicable use level at which the deterioration of saturation magnetization is extremely little in spite of long-term preservation at and under a high temp. and high humidity is obtd. Nonmagnetic inorg. powder having a particle size of <=10μm is preferably incorporated into the magnetic layer. Further, the inorg. powder is preferably inorg. powder of pH >=7.