Three-dimensional X-ray micro-computed tomography of cracks in a furnace cycled air plasma sprayed thermal barrier coating

Using X-ray micro-computed tomography, a total of 3 × 3 mm2 area of an air plasma sprayed (APS) thermal barrier coating (TBC) was imaged with a resolution of 0.76 μm at 60% cyclic furnace life. Over 10,000 X-ray micrographs were used to extract the 3-D geometry of the cracks in the top coat. The true shape, center and location of the cracks with respect to bond coat peak-valley roughness features were obtained, which revealed the real nature of cracking characteristics of APS TBCs.