Effects of the surface configuration of magnetic layers on durability against mechanical stress

This work was carried out in order to improve the durability of metal evaporated tape (ME tape) used in 8mm VCRs. The relationship between the surface configuration of the tape and mechanical stress induced by the impact of a high speed rotating video recording head have been investigated mainly by means of a still-frame life test. The following conclusions have been ascertained. 1) There is an optimum oxygen content level in the Co-Ni magnetic layer in regards to still-frame life. 2) Under low humidity conditions, still-frame life is reduced. 3) Still-frame life is strongly affected by the surface micro roughness (topography) of the magnetic layer, particularly the presence of the steep, high density protrusions which prolong tape life to a great degree.