Evaluation on Fracture Characteristics of TiN Cdramics Film with Scratch Testing. 2nd Report. Application of Wavelet Transform of AE Signals.

Abstract

Many of the ceramic coating material can be exposed to harsh working conditions because of their excellent characteristics. Therefore, for producing superior coating materials, it is necessary to establish a methodology for evaluating the mechanical properties of these materials. In the formedr report, nine kinds of TiN film 5μm 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, it was clarified that fractal dimension m determined AE peak amplitude distributions became grater than three when the fracture mode was cracking, the dimension became between one and three when the mode was chipping, and the dimension became less than one when the mode was flaking. However, it is necessary for evaluating the fracture mechanism to recognize the information on the changes of the fracture modes which is included in an AE event. In this report, wavelet transform(WT)was used to attain the subject. From the experimental results, it was found that the changes of the fracture mode are evaluated by observing the time-frequency analysis with WT.