A. Lynam , A. Rincon Romero , B. Zhang , S. Lokachari , F. Xu , G.J. Brewster , G. Pattinson , T. Hussain
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引用次数: 0
Abstract
Abradable environmental barrier coatings (EBCs) can be implemented to realise crucial gains in gas turbine efficiency. The aim of this study was to better understand how abradable coatings perform when exposed to molten calcium magnesium alumino-silicates (CMAS), one of the key challenges facing current EBC design, and how this exposure affects the mechanical properties of the abradable coatings. In this study, three ytterbium disilicate (Yb2Si2O7) abradable EBCs containing 8, 15 and 22 % porosity were deposited using atmospheric plasma spraying. These coatings were then exposed to CMAS at high temperatures for 0.5 h, 4 h and 100 h. The results show that increasing the overall level of porosity had minimal impact on the degree of CMAS infiltration and interaction observed in the coatings during exposure. Reaction with the CMAS occurred by a dissolution-precipitation mechanism, with a reprecipitated ytterbium disilicate phase and Yb-apatite (Ca2Yb8(SiO4)6O2) crystals noted as the only reaction products. After 100 h CMAS exposure, the erosion resistance of the coatings was investigated. For all the coatings, ductile failure was the main erosion mechanism. The change in phase composition and microstructure after CMAS exposure led to an increase in erosion resistance for all the coatings.
期刊介绍:
Surface and Coatings Technology is an international archival journal publishing scientific papers on significant developments in surface and interface engineering to modify and improve the surface properties of materials for protection in demanding contact conditions or aggressive environments, or for enhanced functional performance. Contributions range from original scientific articles concerned with fundamental and applied aspects of research or direct applications of metallic, inorganic, organic and composite coatings, to invited reviews of current technology in specific areas. Papers submitted to this journal are expected to be in line with the following aspects in processes, and properties/performance:
A. Processes: Physical and chemical vapour deposition techniques, thermal and plasma spraying, surface modification by directed energy techniques such as ion, electron and laser beams, thermo-chemical treatment, wet chemical and electrochemical processes such as plating, sol-gel coating, anodization, plasma electrolytic oxidation, etc., but excluding painting.
B. Properties/performance: friction performance, wear resistance (e.g., abrasion, erosion, fretting, etc), corrosion and oxidation resistance, thermal protection, diffusion resistance, hydrophilicity/hydrophobicity, and properties relevant to smart materials behaviour and enhanced multifunctional performance for environmental, energy and medical applications, but excluding device aspects.