Thermal conductivity and erosion durability of composite two-phase air plasma sprayed thermal barrier coatings

SURFACE & COATINGS TECHNOLOGY

卷:279

Article

Schmitt, Michael P.^1,2  Rai, Amarendra K.³  Zhu, Dongming⁴  Dorfman, Mitchell R.⁵  Wolfe, Douglas E.^1,2,6 

[1] Penn State Univ, Appl Res Lab, University Pk, PA 16802 USA

[2] Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA

[3] Universal Energy Syst Inc, Dayton, OH 45432 USA

[4] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA

[5] Oerlikon Metco US Inc, Westbury, NY 11590 USA

[6] Penn State Univ, Dept Engn Sci & Mech, University Pk, PA 16802 USA

关键词: Thermal barrier coating (TBC);    Air plasma spray;    Low-k;    Rare earth zirconia;    Composite;    Erosion;   

DOI  :  10.1016/j.surfcoat.2015.08.010

来源: Elsevier

【 摘 要 】

To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7 wt.% yttria stabilized zirconia (7YSZ), similar to 1200 degrees C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t', Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by similar to 13% and similar to 25%, respectively. The 40 wt.% t' Low-k composite (40 wt.% t' Low-k 60 wt.% cubic Low-k) showed a similar to 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal conductivity in the composite coating. It was observed that a mere 20 wt.% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability. (C) 2015 Elsevier B.V. All rights reserved.

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