Effect of Chemical Compositions and Surface Morphologies of MCrAlY Coating on Its Isothermal Oxidation Behavior
- 535 Downloads
Chemical composition and surface morphology of MCrAlY coatings are factors which influence the oxidation behavior and the thermal durability of thermal barrier coatings. In this study, Cold-sprayed Ni20Cr10AlY and Ni23Co20Cr8.5Al4.0Ta0.6Y coatings with polished surfaces were employed to study the effect of composition on the oxidation behavior. The cold-sprayed MCrAlY coatings at the as-sprayed and shot-peened surface conditions, along with the low pressure plasma-sprayed MCrAlY coating with sputters adhered weakly on the surface, were employed to investigate the effects of surface morphologies of MCrAlY coatings on their oxidation behavior. Cold-sprayed Ni20Cr10AlY coating exhibited a two-stage oxidation behavior and a higher TGO growth rate than that of the cold-sprayed Ni23Co20Cr8.5Al4.0Ta0.6Y coating at the rapid growth stage. After 10-h oxidation, the TGO on the as-cold-sprayed coating surface was mainly constituted by Al2O3, while the TGO on the coating surface attached with sputters was composed of Al2O3 and Cr/Ni-oxides. After 500-h oxidation, Cr2O3 and porous spinel appeared in the TGO on the surface of the as-cold-sprayed coatings with different compositions. The growth of Cr/Ni-oxides was attributed to the Al depletion. The content of spinel decreased on the cold-sprayed NiCrAlY with a shot-peened surface compared with the as-sprayed coating.
Keywordscold spray composition low pressure plasma spraying MCrAlY coating oxidation behavior surface morphology
This study was financially supported by the National Basic Research Program of China (No. 2007CB707702), and the National Science Fund for Distinguished Young Scholars (No. 50725101).
- 24.Y. Li, C.-J. Li, G.-J. Yang, and L.-K. Xing, Thermal Fatigue Behavior of Thermal Barrier Coatings with the MCrAlY Bond Coats by Cold Spraying and Low-Pressure Plasma Spraying, Surf. Coat. Technol., 2010, doi: 10.1016/j.surfcoat.2010.08.144
- 30.M. Grujicic, C.L. Zhao, W.S. DeRosset, and D. Helfritch, Adiabatic Shear Instability Based Mechanism for Particles/Substrate Bonding in the Cold-Gas Dynamic-Spray Process, Mater. Des., 2004, 25, p 681-688Google Scholar
- 32.G.-S. Huang, Deposition Properties of Cold-Sprayed CoNiCrAlY Coatings Prepared with Nitrogen Gas, Proceedings of the 4th Asian Thermal Spray Conference, C.-J. Li and G.-J. Yang, Ed., Oct. 22-24, 2009 (Xi’an, China), 2009, p 366-369Google Scholar
- 35.Y.-S. Yi and J.-D. Zhang, Alumina Ceramic Material and Its Composite, Chemical Industry Press, 2001, p 93 (in Chinese)Google Scholar