EFFECT OF DIAMOND-LIKE CARBON COATING AND SURFACE-TOPOGRAPHY ON THE PERFORMANCE OF METAL EVAPORATED MAGNETIC TAPES

In this study, metal evaporated (ME) tapes with and without diamondlik e carbon (DLC) coating were tested for friction, wear, and magnetic pe rformance, Performance of fiat DLC ME tape is compared with two non-DL C ME tapes (one being hat and the other with waviness), By using a com mercial VCR as a magnetometer and the Wallace equation, changes in the rms head output level were correlated to changes in head-to-tape spac ing as tape wear occurred during play/rewind cycling tests, Interface stability and recording performance at a 0.6 mu m recording wavelength were measured to bit level resolution using a dropout counter, Some p ause mode and environmental testing were also performed, Tribological performance and magnetic reliability of ME tape was affected by wavine ss of the ME tape surface as well as by the presence of a DLC coating, Waviness of one kind of non-DLC ME tape caused poor magnetic performa nce and Localized wear of the tape surface, but loose wear debris coul d escape contact areas by settling into valleys on the tape surface, I n the case of flat non-DLC ME tape, loose wear debris could not escape from contact areas leading to early failure, DLC coating prevented ca tastrophic abrasive wear and reduction in head-to-tape spacing or inti mate contact during cycling tests, but could not significantly improve the durability of RIE tape, DLC coating reduces asperity compliance a s compared to non-DLC tapes, All ME tapes failed by lateral crack form ation (cracks often propagated through coating defects) driven by long itudinal tape tension or flexing of the tape in the transport, In paus e mode, DLC coating improved magnetic reliability and tribological per formance by preventing the heads from contacting the metallic magnetic layer, Based on this study, a hat tape must be used for magnetic cons iderations and DLC coating is needed to prevent abrasive,Fear and inti mate contact. Reducing the number of coating defects and optimization of the toughness of magnetic and DLC coatings are key parameters for f uture ME tapes. At fixed temperature, high relative humidity leads to severe tape instability and high dropout frequency, At high specific h umidities, lower temperature leads to severe tape instability and high dropout frequency, Bearing ratio curves for the tapes determine the o nset of high friction and tape instability at high humidities.