Objectives

This project focused on the factors controlling the deterioration in performance and final failure of TBCs. An important part of this was viewed to be the mechanical behaviour of the bondcoat, this aspect was considered within this project. The work was subdivided into three key areas. Firstly, work developed the piezospectroscopic method to monitor residual stress in the thermally grown oxide (TGO).

The method relied upon exciting fluorescence of small amounts of Cr3+ ions normally present in the TGO and detecting shifts in the position of the peak. The potential exists to develop piezospectroscopy as a non-destructive method to determine adhesion (lifetime) of TBC. Secondly, the thermal response of TBCs controls life and a better understanding of quantitative measurement method to determine the thermal conductivity of the TBC system is obtained. Thirdly, mechanical performance of the bondcoat was assessed.