The thermal properties of plasma sprayed coating of zirconia stabilized with 8wt% of yttria was studied by the laser flash method. The experimental results were used for the thermal conduction analysis of stabilized zirconia coated materials with a penny-shape crack at interface using the finite element method. The analysis was conducted to find nondestructively the interfacial crack from the surface temperature distribution of coating. It was verified that the interfacial cracks become less detectable with increasing coating thickness and with decreasing crack size. It was also confirmed by the experiment using infrared thermography that fairly good agreement between the measured and real crack size was obtained for the crack diameter not less than 3mm. The results indicated that the thermography method as a new technique was useful for nondestructive testing to detect the interfacial cracks of coated materials.
