Derivative effect of laser cladding on interface stability of YSZ@Ni coating on GH4169 alloy: An experimental and theoretical study

• Published in: Applied surface science 2018-01, Vol.427, p.1105-1113
• Main Authors: Zheng, Haizhong, Li, Bingtian, Tan, Yong, Li, Guifa, Shu, Xiaoyong, Peng, Ping
• Format: Article
• Language: English
• Subjects: First-principles; Interface conjunction; Microcosmic mechanism; Thermal barrier coatings; YSZ@Ni nanoparticles
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2017.09.114

•A new TBC as YSZ@Ni core-shell nanoparticles was manufactured successfully by laser cladding on a GH4169 alloy.•A derivative effect of laser cladding results in the original YSZ@Ni core-shell nanoparticles being translated into the Al2O3 crystal.•The mechanism of ceramic/metal interface cohesion was studied in depth via first-principles and molecular dynamics simulation.•In addition, the derivative product as TGO Al2O3 can improve the oxidation resistance of the metal matrix. Yttria-stabilized zirconia YSZ@Ni core-shell nanoparticles were used to prepare a thermal barrier coating (TBC) on a GH4169 alloy by laser cladding. Microstructural analysis showed that the TBC was composed of two parts: a ceramic and a bonding layer. In places where the ZrO2/Al2O3 eutectic structure was present in the ceramic layer, the Ni atoms diffused into the bonding layer, as confirmed by energy-dispersive X-ray spectroscopy (EDS). The derivative effect of laser cladding results in the original YSZ@Ni core-shell nanoparticles being translated into the Al2O3 crystal, activating the YSZ. The mechanism of ceramic/metal interface cohesion was studied in depth via first-principles and molecular dynamics simulation. The results show that the trend in the diffusion coefficients of Ni, Fe, Al, and Ti is DNi>DFe>DTi>DAl in the melting or solidification process of the material. The enthalpy of formation for Al2O3 is less than that of TiO2, resulting in a thermally grown oxide (TGO) Al2O3 phase transformation. With regard to the electronic structure, the trend in Mulliken population is QO−Ni>QZr−O>QO−Al. Although the bonding is slightly weakened between ZrO2/Al2O3 (QZr−O=0.158