Reliability of obliquely deposited Co-O thin film with carbon protective layer

Advanced ME tape with +5 dB higher output than conventional Hi-8 ME tape at a recording density of 100 kBPI has been developed. It combines an obliquely deposited Co-O magnetic layer and a diamond like carbon (DLC) protective layer. DLC shows higher durability and higher corrosion resistance than other types of protective layer. The main corrosion product found on ME tapes after an accelerated corrosion test was chlorination of Co. DLC is continuous and non-porous even at a thickness of 10 nm, and probably is the reason for drastic improvement of corrosion resistance. Corrosion resistance of the small cassette tape for Consumer-Use Digital VCR including advanced ME tape was evaluated by the Battelle test. Its storage life was evaluated as more than 28 years even in the cassette lid portion.