Microstructure of Thermal Barrier Coatings (TBC's) Obtained by Using Plasma Spraying and VPA Methods

Abstract

Thermal Barrier Coatings are the main type of coatings used for protecting turbine blade surfaces and the surface of modern jet engines combustion chamber parts. Depending on the type of engine element, the coatings are produced as plasma-sprayed MeCrAlY bond-coats with a ceramic outer layer or as Pt-modified aluminide coatings with a ceramic EB-PVD-deposited layer. Currently, research is being conducted on the deposition of a new type of coatings consisting of bond-coats with mulitlayer structure. In the article, the results of the study on the obtainment of TBC's with multilayer structure are presented. To obtain the metallic bond-coat, the process of atmospheric plasma spraying and the out of pack aluminizing (VPA) method were combined. The coatings were deposited on the surface of Rene 80 nickel superalloy. The first layer of the coating was a plasma-sprayed MCrAlY bond-coat, on which a diffusion aluminide layer was deposited with out of pack method. On the bond-coat, a standard ceramic zirconium oxide (ZrO2*20Y2O3) layer was deposited. The microstructure analysis, was conducted, using light and SEM microscopy. The phase and chemical composition analyses were done using EDS and XRD methods.