Phase stability, thermo-physical properties and thermal cycling behavior of plasma-sprayed CTZ, CTZ/YSZ thermal barrier coatings. Issue 8 (1st June 2018)

• Record Type: Journal Article
• Authors: Wang, Jinshuang; Sun, Junbin; Yuan, Jieyan; Jing, Qiangshan; Dong, Shujuan; Liu, Bing; Zhang, Hao; Deng, Longhui; Jiang, Jianing; Zhou, Xin; Cao, Xueqiang
• Is Part Of: Ceramics international. Volume 44:Issue 8(2018)
• Page Start: 9353
• Page End: 9363
• Publication Date: 2018-06-01
• Subjects: Thermal barrier coating -- Phase stability -- Thermo-physical properties -- Thermal cycling; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.02.149
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: ZrO2 co-stabilized by CeO2 and TiO2 with stable, nontransformable tetragonal phase has attracted much attention as a potential material for thermal barrier coatings (TBCs) applied at temperatures > 1200 °C. In this study, ZrO2 co-stabilized by 15 mol% CeO2 and 5 mol% TiO2 (CTZ) and CTZ/YSZ (zirconia stabilized by 7.4 wt% Y2 O3 ) double-ceramic-layer TBCs were respectively deposited by atmospheric plasma spraying. The microstructures, phase stability and thermo-physical properties of the CTZ coating were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric-differential scanning calorimeter (TG-DSC), laser pulses and dilatometry. Results showed that the CTZ coating with single tetragonal phase was more stable than the YSZ coating during isothermal heat-treatment at 1300 °C. The CTZ coating had a lower thermal conductivity than that of YSZ coating, decreasing from 0.89 W m −1 K −1 to 0.76 W m −1 K −1 with increasing temperature from room temperature to 1000 °C. The thermal expansion coefficients were in the range of 8.98 × 10 −6 K −1 – 9.88 ×10 −6 K −1 . Samples were also thermally cycled at 1000 °C and 1100 °C. Failure of the TBCs was mainly a result of the thermal expansion mismatch between CTZ coating and superallloy substrate, the severe coating sintering and the reduction-oxidation of cerium oxide. The thermal durability of the TBCs at 1000 °C can be effectively enhanced by using a YSZ buffer layer, while the thermal cycling life of CTZ/YSZ double-ceramic-layer TBCs at 1100 °C was still unsatisfying. The thermal shock resistance of the CTZ coating should be improved; otherwise the promising properties of CTZ could not be transferred to a well-functioning coating.