Use of indentation technique to measure elastic modulus of plasma-sprayed zirconia thermal barrier coating

摘要

Elastic modulus of an yttria partially stabilized zirconia (YSZ) thermal barrier coating (TBC) was evaluated with a Knoop indentation technique. The measured elastic modulus values for the coating ranged from 68.4 (+-) 22.6 GPa at an indentation load of 50 g to 35.7 (+-) 9.8 at an indentation load of 300 g. At higher loads, the elastic modulus values did not change significantly. This steady-state value of 35.7 GPa for ZrO(sub 2) TBC agreed well with literature values obtained by the Hertzian indentation method. Furthermore, the measured elastic modulus for the TBC is lower than that reported for bulk ZrO(sub 2) ((approx) 190 GPa). This difference is believed to be due to the presence of a significant amount of porosity and microcracks in the TBCs. Hardness was also measured.