POWDER FOR LOWER LAYER OF COATING TYPE MAGNETIC RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To obtain powder for a lower layer of a coating type magnetic recording medium having a multilayered structure having a non-magnetic layer (the lower layer), capable of simultaneously satisfying surface smoothness and conductivity of the lower layer as the powder for the lower layer. SOLUTION: The powder for the lower layer of the coating type magnetic recording medium is formed by mixing an iron oxide based powder consisting of acicular particles of iron oxide or iron oxide hydrate in water in the presence of carbon black and a surfactant.