Combined Oxidation And Corrosion Resistance Of Suspension Plasma Sprayed Thermal Barrier Coatings

Thermal Barrier Coatings (TBCs), manufactured with suspension plasma spray (SPS), are increasingly interesting for potential applications in gas turbines due to their promising cyclic life obtained by thermal cyclic fatigue (TCF) tests. However, corrosion often occurs alongside thermal fatigue and a combined resistance to both is highly desirable. The current study focuses on understanding the combined corrosion and TCF resistance of a SPS TBC by thermally cycling the samples after exposing them to a corrosive atmosphere. Corrosion tests were conducted at 780 ^oC using a mixed-gas (1SO₂-0.1CO-20CO₂-N₂(bal.) in vol. %) for 168h. They were later thermally cycled between 100-1100 ^oC with a 1h hold time at 1100 ^oC. Corrosion test results indicated that damage started from the edges and it caused a significant drop in the TCF life compared to the pure TCF tests. Failure mechanism during corrosion and the accelerated failure during TCF are discussed in the current paper.