STATISTICAL EVALUATION OF VICKER INDENTATION TEST-RESULTS FOR THERMALLY SPRAYED MATERIALS

In this experimental investigation, Vicker's microhardness tests were used to assess the heterogeneity of a wide range of thermally sprayed coatings. Three different loads were used to evaluate the influence of the test volume on load-hardness dependence. Statistical elaboration of obtained results were performed by using variance analysis, Student 's and Fisher's tests, Gaussian and Weibull distributions, Meyer's the ory, in order to separate variation due to scatter of data and due to different materials properties. A load-hardness dependence was evidenc ed especially for ceramic coatings, due to their brittle nature, where as for the two metallic coatings tested (Ti-6Al-4V and CoNiCrAlY) a bi modal distribution seems to exist at small loads.