Effect of heat treatment and synergistic rare-earth modified NiCrAlY on bonding strength of nanostructured 8YSZ coatings

• DOI: 10.1016/j.apsusc.2019.02.247
• Publication Date: 2019-03-01T23:55:16Z
• Authors: Feifei Zhou; Zhenguo Zhang; Saiyue Liu; Lan Wang; Jin Jia; You Wang; Xue Gong; Junfeng Gou; Chunming Deng; Min Liu
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract In this paper, the nanostructured 8YSZ coatings and two kinds of bond coatings including NiCrAlY and NiCrAlYCe coatings were deposited by atmospheric plasma spraying onto nickel-based superalloys. The microstructure of as-sprayed coatings and the effect of heat treatment on bonding strength of NiCrAlY/8YSZ and NiCrAlYCe/8YSZ coatings were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), together with energy dispersive spectrum (EDS) and X-ray diffraction (XRD) analysis. The results indicate that the coatings exhibit typical bi-modal microstructure and the grain size of 8YSZ coatings keeps nanostructure. As for 8YSZ coatings, the phase transformation occurs from t phase to t′ phase during plasma spraying and the heat treatment does not change the phase structure. The heat treatment and rare-earth modified NiCrAlY coatings play an important role in enhancing the bonding strength of as-sprayed coatings significantly compared with NiCrAlY/8YSZ coatings. The bonding strength of NiCrAlYCe/8YSZ coatings whose temperature of the heat treatment is 800 °C @ 6 h can reach 48.9 MPa, which is 1.5 times than that of as-sprayed NiCrAlYCe/8YSZ coatings.