Tribological comparisons of particulate magnetic tape coatings in destructive wear testing

Abstract

Particulate magnetic tape coatings are composed of many ingredients, all of which either add or subtract from the overall durability of the tape coating. The ingredients that make up the surface of the coating such as the binders and lubricants are the ones of greatest interest in this work since they determine its wear performance. A test was developed that subjects the coating to accelerated wear conditions, until coating failure, to determine how each ingredient contributes to the overall wear properties of the tape. The test measures tape tensions at two points before and after the wear surface using a continuous spliced loop of tape sliding at any constant speed from 1 to 6 m/s under controlled humidity. Coating failure occurred when the friction coefficient increased above 0.3 and coating debris is deposited at the point of wear on the non-rotating tape guides. The debris is removed from the guides and visually rated on a scale of 0 to 4. Tape coatings that were studied contained Co– γFe 2O 3, iron metal particles (MP), and various backside coatings on these tapes. All formulation variables were studied but the main focus of this study is on the effect of variable internal and surface applied lubricants along with analysis of the cycled tape surface and the debris formed in an attempt to determine the failure mechanism.