Evaluation on fracture characteristics of TiN ceramics film with scratch testing (3rd report, evaluation of scratch mark condition by AE signals)

Many of the ceramic coating materials can be exposed to harsh working conditions. Therefore, for producing superior coating materials, it is necessary to establish a methodology for evaluating the mechanical properties of these materials. Until the former report, nine kinds of TiN film 5 μm thick, which were deposited on the different parent materials under different N2 partial pressure, were scratched and the relationship between the characteristics of the detected acoustic emission (AE) signals and the fracture modes of the film (i.e. cracking, chipping and flaking) was investigated. As the results, the following things became clear: (1) the fracture modes were classified by fractal dimension m determined AE peak amplitude distributions. (2) the changes of the fracture mode were evaluated by observing the analysis with wavelet transform (WT). In this report, time fluctuation signals of wavelet coefficient, multiple analysis and fuzzy reasoning were used to evaluate the scratch mark conditions. From the experimental results, it was found that the conditions were evaluated by this method.