DRUM FOR VIDEOTAPE RECORDER

摘要

PURPOSE:To improve the traveling performance of a cast Al-Si alloy drum used in a videotape recorder to a magnetic tape by immersing the drum in an aqueous alkali soln. to carry out the selective etching of the drum surface. CONSTITUTION:The surface layer 5a of the Al matrix 5 of a cast Al-Si alloy drum is dissolved to project Si particles of 0.1-3.0mum diameter dispersed almost uniformly in the Al matrix 5. The contact of the surface 7a of the magnetic material of a metallic thin film type magnetic tape 7 with the Al matrix 5 is reduced, adhesion on the interface between them is prevented, and the wear resistance of the surface of the magnetic tape is improved to prevent the damage.