Wear behavior of aluminum-coated glass compared to uncoated glass investigated by cyclic wear tests in the micrometer scale

Micro wear tests have been conducted on soda lime glass covered with a 4.5 mu m aluminum film and on an uncoated glass substrate. High resolution lateral force-displacement measurements were carried out with a spherical diamond indenter of 6 mu m radius while the normal force was kept constant. The wear behavior was investigated for different normal loads (100 mN, 200 mN), different scratch lengths (10 mu m, 40 mu m) and different lateral sliding speed (5 mu m/s, 10 mu m/s, 20 mu m/s). These conditions were used as a model for the characterization of surface damage by hard wear particles. The average friction coefficient and the average normal displacement per cycle were calculated and their change was used for the characterization of the wear behavior. Significant changes could be observed in the dependence on the wear parameters and the cycle number. Thus, wear dominated by plastic deformation and fracture-dominated wear could be distinguished. The soft aluminum coating on the brittle glass prevents fracture-dominated wear of the glass even after the failure of the coating. The wear rate of the glass is considerably decreased if only wear by plastic deformation occurs. (c) 2006 Elsevier B.V. All rights reserved.