MICROTRIBOLOGY OF METAL-PARTICLE, BARIUM FERRITE AND METAL EVAPORATED MAGNETIC TAPES

Atomic force microscopy and friction force microscopy have been used to conduct microtribological studies on high-coercivity metal particle (MP), barium ferrite and metal evaporated (ME) tapes which are being developed for ultra high-density magnetic recording. Microfriction, microscratching, microwear and nanoindentation hardness of all tapes have been measured. For comparisons, macrofriction measurements were also made. We find that macro- and microscale friction values of all tapes are comparable with each other. ME tapes are harder and more scratch and wear resistant than the MP and barium ferrite tapes. However, at high enough load or at larger number of cycles, magnetic film of the ME tape breaks up catastrophically unlike particulate tapes. Thus, ME tape may be less desirable from a tribological viewpoint unless it can be well lubricated topically and/or be made more ductile to minimize the probability of catastrophic failure. We have also observed the cracking near the slit edges of the ME tape which may result in the debris generation during use.