Abstract
We propose a new hybrid technique of AE, corrosion potential and FEM for studying the fracture mechanism of hard surface films during micro-Vickers indentation. This method makes it possible to determine the fracture strength of the film when hard film is deposited on soft substrate. Both the AE and corrosion potential fluctuation of CVD-TiN film deposited on AISI304 steel in hydrochloric acid (1 mol// HC1 + 0.01 mol KSCN) were simultaneously monitored during Vickers indentation test. We observed characteristic potential change in mV scale during loading to 20 N. Timing of the potential fluctuations coincided well with strong AE events. Both the AE and potential fluctuation were found to be produced by the Mode-I fracture of the film bending during loading. The number of equidistance step-wise terrace or rippled cracks observed in pyramidal indentation agreed well with potential fluctuation numbers.
