Plasma-sprayed La2Ce2O7 thermal barrier coatings against calcium–magnesium–alumina–silicate penetration

• Published in: Journal of the European Ceramic Society Vol. 34; no. 10; pp. 2553 - 2561
• Main Authors: Gao, Lihua, Guo, Hongbo, Gong, Shengkai, Xu, Huibin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2014
• Subjects: Calcium–magnesium–alumina–silicate (CMAS); La2Ce2O7 (LC); Microstructure; Thermal barrier coatings (TBCs); Yttria stabilized zirconia (YSZ); Thermal barrier coatings (TBCs); Calcium–magnesium–alumina–silicate (CMAS); Yttria stabilized zirconia (YSZ); Microstructure; La2Ce2O7 (LC)
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2014.02.031

As one of promising thermal barrier coating (TBC) candidates, La2Ce2O7 (LC) has attracted increasing attention because of its low thermal conductivity and potential capability to be operated above 1250°C. In this paper, the microstructure evolution and mechanical properties of the plasma-sprayed LC TBC with calcium–magnesium–alumina–silicate (CMAS) glassy deposits at 1250°C were investigated. Due to chemical reaction between the CMAS deposits and LC coating, a dense sealing layer, mainly composed of Ca2(LaxCe1−x)8(SiO4)6O6−4x and CeO2, was formed on the coating after heat-treatment at 1250°C and effectively prevented CMAS from further penetration. The interaction layer had the micro-hardness of ∼10–12GPa, relatively harder than the LC coating.