Characteristic parameter analysis of acoustic emission signals under tip loading on Al₂O₃ ceramic coating

In order to investigate the feasibility of the detector on evaluating the bonding strength of surface coatings on the remanufactured components,Al₂O₃ ceramic coating,as the research objects,were fabricated,and then were tested by superficial indentation testing.The time distribution curves of acoustic emission(AE) primary parameters including amplitude,count,energy and root mean square value(RMS) were extracted and analyzed.The waveforms of inflection point were read.And the sectional morphologies of indentation points were observed by scanning electronic microscope.The results of the experiments indicated that the interfaces occurred surely fracture failure when there was a significant AE signal mutations.This testing equipment could effectively induce and define coatings cracking failure. And AE signals could be an effective criterion to detect the coating failure.There into,the amplitude possessed a better capability to indicate the crack propagation process.The energy was more sensitive of the fracture phenomena and appropriate for evaluating the bonding strength.