Thermomechanical behavior of plasma-sprayed zirconia thermal barrier coatings.
The effect of coating porosity and thickness on the resistance to damage of yttria stabilized zirconia thermal barrier coatings in an oxidizing environment by thermal cycling was evaluated. Hardness and elastic modulus of an as-processed porous coating were lower than those of a dense coating and the porous coating failed after fewer thermal cycles. Similarly, specimen with a thicker coating failed after fewer thermal cycles than specimen with a thinner coating. The earlier failure of the porous coating is due to lower fracture toughness and enhanced oxidation of the coating/substrate interface, whereas, the earlier failure of the thick coating is due to higher thermal transient stresses that developed in the coating during thermal cycling. Generally, an increase in coating density led to initial increase in both hardness and elastic modulus with increasing thermal cycles. However, hardness and density gradually decreased as the number of thermal cycles increase because of microcracks formation and growth. Microscopic observations indicated that the formation of multiple microcracks and their subsequent growth and coalescence led to final coating failure.
- Research Organization:
- Argonne National Lab., IL (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 10706
- Report Number(s):
- ANL/ET/CP-95982; TRN: AH200127%%288
- Resource Relation:
- Conference: 22nd Annual Conference and Exposition on Composites, Advanced Ceramics, Material and Structure, Cocoa Beach, FL (US), 01/20/1998--01/23/1998; Other Information: PBD: 1 Apr 1998
- Country of Publication:
- United States
- Language:
- English
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