Microstructural characterization of plasma sprayed Ln2 Zr2 O7 thermal barrier coatings by electron microscopy methods

Microsc Res Tech. 2020 May;83(5):523-530. doi: 10.1002/jemt.23441. Epub 2020 Jan 22.

Abstract

The presented article characterized microstructural aspects of thermal barrier coatings (TBCs) analysis using methods of electron microscopy such as electron backscatter diffraction (EBSD), transmission/scanning electron microscopy (S/TEM), and TEM. The analyzed TBC system is based on gadolinium zirconate deposited by air plasma spraying method, and additionally, it was subjected to an oxidation test for 500 hr at a temperature of 1,100°C. Moreover, the morphological characterization of feedstock powder was showed. EBSD analysis revealed the inhomogeneity of feedstock materials in the form of complex phase composition. In the case of deposited coating, this method was used to characterize the crystallite size of zirconate coating and phase composition of thermally grown oxide zone. S/TEM and TEM analysis showed morphological details of this zone but not revealed such phase as perovskite oxide of GdAlO3 type.

Keywords: EBSD; S/TEM; TBC; TEM; morphology characterization.