AN INVESTIGATION OF THE ARCHIVABILITY OF METAL-PARTICLE TAPE

We studied the rate of degradation of the data storage capability of t hree commercial and two experimental metal particle (MP) tapes in an i mpinging jet geometry designed to eliminate irreproducibility in accel erated atmospheric testing. Both the bulk loss of saturation magnetiza tion and a profile of the loss of magnetization through the media were measured. The most corrosion-resistant of the commercial tapes lost l ess than 5% of its magnetization from the top 25% of the media after 2 0 days of exposure to an intensified Battelle Class II environment. Th e experimental tapes lost even less. Thus at least one commercial MP t ape exhibited substantial corrosion resistance under direct exposure t o a strongly corrosion-accelerating environment. Furthermore, the loss of magnetization proceeded nearly uniformly throughout the media, whi ch agreed with the conclusion that the particles were well-armored aga inst corrosive species. The corrosion resistance of the best of the MP media listed above was no worse and perhaps even better than samples of chromium dioxide media that accompanied the MP coupons in every exp eriment.