Pages 211-212
In situ observation of the mechanical failure behavior was conducted of different kinds of the plasma sprayed thermal barrier coating (TBC) systems by means of an optical microscopy under the static loadings at ambient temperature; as the most fundamental aspect, in order to clarify the failure mechanism of TBCs. Several kinds of TBC systems were prepared by using different coating parameters of ether water plasma spraying or air plasma spraying process for top-coat, heat treatment condition and so forth. Mechanical tensile or compressive loadings were applied progressively to the TBC specimen in the four-point bending test methodology. The influence of TBC microstructure on the crack initiation and propagation behavior was investigated in detail. Furthermore, the TBC failure was quantitatively evaluated in relation with the mechanical strain applied on the top-coat surface.
