An investigation of nano-wear during contact recording

Abstract

A method for measuring wear phenomena at the nano-scale is presented. It involves the introduction of micron sized indentations on the sliding surface which are 10–20 nm deep to act as reference for the measurement of wear. The changes in the size and depth of these indentations as a function of sliding time are monitored with an atomic force microscope. The method has been applied to measure wear on a contact recording head consisting of a diamond-like carbon wear pad of physical dimensions of 10 by 35 μm, under development for use in magnetic hard disks. Constant speed drag tests and sweep tests were conducted in the study. The wear coefficients obtained are of the order of 10 −10. These results correspond to a wear rate of 4.5 nm per week for constant speed drag testing and between 9 and 12 nm per week for sweep testing at a nominal load of 350–400 μN.