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

Abstract

Abstract 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 ZrO 2 /Al 2 O 3 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 Al 2 O 3 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 D Ni > D Fe > D Ti > D Al in the melting or solidification process of the material. The enthalpy of formation for Al 2 O 3 is less than that of TiO 2 , resulting in a thermally grown oxide (TGO) Al 2 O 3 phase transformation. With regard to the electronic structure, the trend in Mulliken population is Q O−Ni > Q Zr−O > Q O−Al . Although the bonding is slightly weakened between ZrO 2 /Al 2 O 3 ( Q Zr−O = 0.158 Q O−Ni = 0.220) compared to that in ZrO 2 /Ni, TGO Al 2 O 3 can improve the oxidation resistance of the metal matrix. Thus, by comparing the connective and diffusive processes, our findings lay the groundwork for detailed and comprehensive studies of the laser cladding process for the production of composite materials.