Air plasma-sprayed high-entropy (Y0.2Yb0.2Lu0.2Eu0.2Er0.2)3Al5O12 coating with high thermal protection performance
Kailun Wang, Jinpeng Zhu, Hailong Wang, Kaijun Yang, Yameng Zhu, Yubin Qing, Zhuang Ma, Lihong Gao, Yanbo Liu, Sihao Wei, Yongchun Shu, Yanchun Zhou, Jilin He
Abstract
Abstract High-entropy rare-earth aluminate (Y 0.2 Yb 0.2 Lu 0.2 Eu 0.2 Er 0.2 ) 3 Al 5 O 12 (HE-RE 3 Al 5 O 12 ) has been considered as a promising thermal protection coating (TPC) material based on its low thermal conductivity and close thermal expansion coefficient to that of Al 2 O 3 . However, such a coating has not been experimentally prepared, and its thermal protection performance has not been evaluated. To prove the feasibility of utilizing HE-RE 3 Al 5 O 12 as a TPC, HE-RE 3 Al 5 O 12 coating was deposited on a nickelbased superalloy for the first time using the atmospheric plasma spraying technique. The stability, surface, and cross-sectional morphologies, as well as the fracture surface of the HE-RE 3 Al 5 O 12 coating were investigated, and the thermal shock resistance was evaluated using the oxyacetylene flame test. The results show that the HE-RE 3 Al 5 O 12 coating can remain intact after 50 cycles at 1200 °C for 200 s, while the edge peeling phenomenon occurs after 10 cycles at 1400 °C for 200 s. This study clearly demonstrates that HE-RE 3 Al 5 O 12 coating is effective for protecting the nickel-based superalloy, and the atmospheric plasma spraying is a suitable method for preparing this kind of coatings.