Thermal cycling behavior and bonding strength of single-ceramic-layer Sm2Zr2O7 and double-ceramic-layer Sm2Zr2O7/8YSZ thermal barrier coatings deposited by atmospheric plasma spraying. Issue 11 (15th August 2016)

• Record Type: Journal Article
• Authors: Wu, H.X.; Ma, Z.; Liu, L.; Liu, Y.B.; Wang, D.Y.
• Is Part Of: Ceramics international. Volume 42:Issue 11(2016)
• Page Start: 12922
• Page End: 12927
• Publication Date: 2016-08-15
• Subjects: Thermal barrier coatings -- Bonding strength -- Thermal cycling lifetime -- Rare-earth zirconates; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2016.05.062
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The single-ceramic-layer (SCL) Sm2 Zr2 O7 (SZO) and double-ceramic-layer (DCL) Sm2 Zr2 O7 (SZO)/8YSZ thermal barrier coatings (TBCs) were deposited by atmospheric plasma spraying on nickel-based superalloy substrates with NiCoCrAlY as the bond coat. The mechanical properties of the coatings were evaluated using bonding strength and thermal cycling lifetime tests. The microstructures and phase compositions of the coatings were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The results show that both coatings demonstrate a well compact state. The DCL SZO/8YSZ TBCs exhibits an average bonding strength approximately 1.5 times higher when compared to the SCL SZO TBCs. The thermal cycling lifetime of DCL SZO/8YSZ TBCs is 660 cycles, which is much longer than that of SCL 8YSZ TBCs (150 cycles). After 660 thermal cycling, only a little spot spallation appears on the surface of the DCL SZO/8YSZ coating. The excellent mechanical properties of the DCL LZ/8YSZ TBCs can be attributed to the underlying 8YSZ coating with the combinational structures, which contributes to improve the toughness and relieve the thermal mismatch between the ceramic layer and the metallic bond coat at high temperature.