A comparison between novel Gd2Zr2O7 and Gd2Zr2O7/YSZ thermal barrier coatings fabricated by plasma spray-physical vapor deposition

• Published in: Rare metals 2021-08, Vol.40 (8), p.2244-2253
• Main Authors: Zhu, Ren-Bo, Zou, Jian-Peng, Mao, Jie, Deng, Zi-Qian, Zhang, Xiao-Feng, Deng, Chun-Ming, Liu, Min
• Format: Article
• Language: English
• Subjects: Adhesive strength; Biomaterials; Ceramic coatings; Chemistry and Materials Science; Columnar structure; Energy; Fracture toughness; Materials Engineering; Materials Science; Metallic Materials; Nanoscale Science and Technology; Original Article; Physical Chemistry; Physical vapor deposition; Quenching; Shock resistance; Spherical plasmas; Spherical powders; Tensile tests; Thermal barrier coatings; Thermal mismatch; Thermal resistance; Thermal shock; Yttria-stabilized zirconia
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-020-01534-x

Spherical Gd 2 Zr 2 O 7 hollow powders with a mean size of 8.8 μm were fabricated as feedstock for thermal barrier coatings (TBCs) by spray-drying. The single-ceramic-layer (SCL) Gd 2 Zr 2 O 7 TBCs and double-ceramic-layer (DCL) Gd 2 Zr 2 O 7 /YSZ TBCs with quasi-columnar structure were successfully fabricated by plasma spray-physical vapor deposition (PS-PVD). Tensile and water-quenching tests were applied to evaluate TBCs performances. The results show that adhesion strength of SCL Gd 2 Zr 2 O 7 TBCs and DCL Gd 2 Zr 2 O 7 /YSZ TBCs is 36.5 MPa and 15.4 MPa, respectively. The delamination of SCL Gd 2 Zr 2 O 7 TBCs and DCL Gd 2 Zr 2 O 7 /YSZ TBCs in the tensile test takes place at the middle and bottom of Gd 2 Zr 2 O 7 layer, respectively, due to relatively lower fracture toughness of Gd 2 Zr 2 O 7 layer. After 40 cycles of water-quenching test, DCL Gd 2 Zr 2 O 7 /YSZ TBC surface keeps relatively intact, while SCL Gd 2 Zr 2 O 7 TBC surface shows 20% visible destroyed regions, which demonstrates that DCL Gd 2 Zr 2 O 7 /YSZ TBCs have a better thermal shock resistance than SCL Gd 2 Zr 2 O 7 TBCs. The cracks in the SCL system propagate near thermally grown oxide (TGO) due to thermal mismatch and TGO growing stress, while cracks in the DCL system propagate in the Gd 2 Zr 2 O 7 layer due to its relatively lower fracture toughness.