Thermal barrier coatings (TBCs) are used in industrial and land-based gas turbine engines to insulate metallic components such as turbine blades and vanes from high temperature. TBCs on rotating components of a gas turbine engine, especially turbine blades, are susceptible to erosion during their service. Erosion leads to undesirable material loss and results in inferior performance of components. Therefore, a detailed understanding of erosion mechanisms in TBCs when subjected to erosion test conditions similar to real service conditions is desirable.

Novelty of this work relates to systematic investigation of the influence of various microstructural features of plasma sprayed TBCs such as pores, cracks (vertical), columns, column gaps and mechanical properties such as hardness and fracture toughness on the erosion performance and erosion mechanisms. Erosion tests were performed at two different erodent impact angles (90º and 30º) on eleven microstructurally different 7-8wt. % TBCs deposited by plasma spray route. Erosion rates were calculated for the investigated TBCs and their erosion mechanisms were examined by SEM analysis of post-eroded specimens.

It was shown that the erosion performance of TBCs had strong correlation to microstructure where columnar micro-structured TBCs and dense vertically crack (DVC) TBCs exhibited superior erosion resistance compared to the lamellar micro-structured TBCs. Furthermore, in this case, mechanical properties such as fracture toughness dictated the erosion resistance of TBCs.