Use of ultramicroindentation to evaluate the degradation of sputtered coatings

The aim of this research work was to study the influence of chemical degrad ation on the mechanical properties of the non-degraded zones of sputtered W -N-Ti coatings. For this, an ultramicroindentation technique has been used before and after degradation, either on the zones between the pits in the c orroded samples, or on the non-oxidised layers after removal of the top deg raded layers. By using different applied loads it was possible to obtain re sults with and without the influence of the substrate. Thus, two types of r esults were obtained, those determined by using an empirical model, which e liminates the influence of the substrate, and those measured directly. Very small differences of less than 20% were obtained in the measured value s before and after degradation, indicating that the non-degraded zones main tain their as-deposited mechanical properties. (C) 1998 Elsevier Science Lt d. All rights reserved.