, Volume 21, Issue 3-4, pp 416-424
Date: 02 Mar 2012

Deposition and Characteristics of Submicrometer-Structured Thermal Barrier Coatings by Suspension Plasma Spraying

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Abstract

In the field of thermal barrier coatings (TBCs) for gas turbines, suspension plasma sprayed (SPS) submicrometer-structured coatings often show unique mechanical, thermal, and optical properties compared to conventional atmospheric plasma sprayed ones. They have thus the potential of providing increased TBC performances under severe thermo-mechanical loading. Experimental results showed the capability of SPS to obtain yttria stabilized zirconia coatings with very fine porosity and high density of vertical segmentation cracks, yielding high strain tolerance, and low Young’s modulus. The evolution of the coating microstructure and properties during thermal cycling test at very high surface temperature (1400 °C) in our burner rigs and under isothermal annealing was investigated. Results showed that, while segmentation cracks survive, sintering occurs quickly during the first hours of exposure, leading to pore coarsening and stiffening of the coating. In-situ measurements at 1400 °C of the elastic modulus were performed to investigate in more detail the sintering-related stiffening.

This article is an invited paper selected from presentations at the 2011 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Thermal Spray 2011: Proceedings of the International Thermal Spray Conference, Hamburg, Germany, September 27-29, 2011, Basil R. Marple, Arvind Agarwal, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and André McDonald, Ed., ASM International, Materials Park, OH, 2011.