IDENTIFICATION OF CRACKS GENERATED BY INDENTATION EXPERIMENTS IN HARD-COATING SYSTEMS

In this work, depth-sensing indentation measurements were applied to Z r-B-N and Zr-B monolayers as well as to multilayer systems of the same materials (two-, four- and 16-layer samples). The coatings were depos ited on to Ck 35 carbon steels by reactive (Zr-B-N) and non-reactive ( Zr-B) d.c. magnetron sputtering. Crack-formation processes during the penetration of the indenter were examined by analysis of the load-inde ntation data and by scanning electron microscopy (SEM). The analysis o f the load-indentation data was performed by using averaging, smoothin g and numerical differentiation procedures. Correlations between the r esults of the data analysis and the SEM observations are outlined, and the advantages of multilayer systems are demonstrated. (C) 1998 Elsev ier Science S.A. All rights reserved.