Solidification Behavior of YSZ@Ni Nanoparticles during Laser Cladding Process

Abstract

In this study, yttria-stabilized zirconia (YSZ) nanoparticles with a core-shell structure (YSZ@Ni) were used to produce a YSZ/metal thermal barrier coating by the laser cladding process. The surface morphology, phase composition, and elemental distribution of the cladding layer were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS), respectively. Splashing of YSZ nanoparticles during the cladding process was reduced when they were encapsulated with nickel. It was found that primary phases of elliptically shaped YSZ and YSZ/(FeCr₂O₄) eutectic nanostructures formed in the center of the molten pool, whereas equiaxed YSZ crystals formed along the edges after the laser cladding. The results showed that aggregation of Ni was observed in the interlayer between the ceramic coating and the substrate. Ni-rich spheres were observed around the equiaxed YSZ crystals. Furthermore, the solidification behavior of YSZ@Ni core-shell nanoparticles was analyzed by studying the thermodynamics and kinetics.