Evaluation of Effect of Process Conditions on Microstructures in Plasma Sprayed Coating by In Situ Laser AE
In recent years, a thermal barrier coating technology becomes more important because it is required to develop materials which avoid high-temperature oxidation and corrosion. In order to ensure reliability of coating, it is necessary to understand microfracture criterion in terms of stress distribution and fracture morphology. The objective of this study is to clarify the damage generation process by comparing Acoustic Emission AE) generation behavior and thermal stress simulation result based on heat history measurement. Al2O3 as the top coat (TC) and NiCrAlY as the bond coat (BC) were sprayed to SUS304 disc or plate as a base material. AE in cooling process were detected by laser heterodyne interferometer after spraying finished. Two-dimensional axisymmetric mesh for samples was made and transient heat conductivity was analyzed for various boundary conditions. Then, using the obtained heat history, transient heat stress was analyzed and the distribution of stress elements was calculated. The fracture process of ceramic coating was evaluated from these experiments and analyses.
Seung-Seok Lee, Joon Hyun Lee, Ik Keun Park, Sung-Jin Song, Man Yong Choi
K. Taniguchi et al., "Evaluation of Effect of Process Conditions on Microstructures in Plasma Sprayed Coating by In Situ Laser AE", Key Engineering Materials, Vols. 321-323, pp. 1443-1446, 2006