Protectiveness of Pt and Gd2Zr2O7 layers on EB-PVD YSZ thermal barrier coatings against calcium–magnesium–alumina–silicate (CMAS) attack

• Published in: Ceramics international Vol. 41; no. 9; pp. 11662 - 11669
• Main Authors: Wang, Lu, Guo, Lei, Li, Zhuomin, Peng, Hui, Ma, Yue, Gong, Shengkai, Guo, Hongbo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-11-2015
• Subjects: Calcium–magnesium–aluminum–silicon (CMAS); Chemical attack; Coating; Deposition; Electroplating; Gd2Zr2O7 layer; Platinum; Protective coatings; Pt film; Thermal barrier coatings; Thermal barrier coatings (TBCs); Yttria stabilized zirconia; Yttria stabilized zirconia (YSZ); Calcium–magnesium–aluminum–silicon (CMAS); Thermal barrier coatings (TBCs); Yttria stabilized zirconia (YSZ); Gd2Zr2O7 layer; Pt film
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2015.05.128

Thermal barrier coatings (TBCs) are susceptible to degradation caused by environmental deposits mainly composed of calcium–magnesium–aluminum–silicon (CMAS). In this work, the degradation of electron beam physical vapour deposition (EB-PVD) yttria stabilized zirconia (YSZ) TBC due to CMAS attack was investigated. To protect the YSZ coating, a Pt film and a Gd2Zr2O7 (GZO) layer were deposited onto the YSZ coating surface by electroplating and EB-PVD, respectively. The coatings were heat treated at 1250°C for 4h with CMAS deposits, and their microstructure and chemical composition after CMAS attack were investigated. Electroplating a dense and defect-free Pt film on YSZ coating could provide effective protection from CMAS attack, but EB-PVD GZO coating was unable to prevent molten CMAS infiltration, mainly due to the large inter-columnar gaps. The associated mechanisms were discussed in detail.