Femtosecond pulsed laser damage characteristics of 7% Y2O3-ZrO2 thermal barrier coating

Ablation characteristics of 7% yttria stabilized zirconia thermal barrier coating, deposited by the electron beam physical vapor deposition method, was studied using a femtosecond pulsed laser. The single-pulse damage threshold fluence for the coating was determined to be 1.64 J cm-2. The threshold fluence was not appreciably dependent on the initial roughness of the coating surface. An incubation effect, i.e., a decrease in the damage threshold fluence with an increase in number of pulses incident at a given location, was observed for this coating. Based on the damage morphology generated by single and multi-pulse interactions, a mechanism for the incubation effect was proposed. (orig.)