Friction in Magnetic Tapes II: Role of Physical Properties

Abstract

Experiments were conducted to examine the relationship between the coefficient of friction and the physical properties of magnetic-tape surfaces. Based on the experimental data, it was observed that the coefficient of friction has a strong dependence on complex modulus of the materials in contact. Softening of the polymer binder of the tape surface at elevated temperatures results in an increase in friction. This demonstrates the need for a relatively hard binder with a softening temperature (at the appropriate rate of deformation) above the maximum operating condition. Surface topography has a strong influence on friction. A rougher surface results in higher contact stress at the contacting asperities, and, therefore, in less real contact area and lower friction. A rougher surface, however, may result in higher head wear and poorer magnetic signal amplitude. These observations demonstrate the need for optimization of the surface topography to maintain high performance of a magnetic-tape product.