AN INVESTIGATION OF NANO-WEAR DURING CONTACT RECORDING

A method for measuring wear phenomena at the nano-scale is presented. It involves the introduction of micron sized indentations on the slidi ng surface which are 10-20 nm deep to act as reference for the measure ment of wear. The changes in the size and depth of these indentations as a function of sliding time are monitored with an atomic force micro scope. The method has been applied to measure wear on a contact record ing head consisting of a diamond-like carbon wear pad of physical dime nsions of 10 by 35 mu m, under development for use in magnetic hard di sks. Constant speed drag tests and sweep tests were conducted in the s tudy. The wear coefficients obtained are of the order of 10(-10). Thes e results correspond to a wear rate of 4.5 nm per week for constant sp eed drag testing and between 9 and 12 nm per week for sweep testing at a nominal load of 350-400 mu N.