Design of core-shell structured YSZ@Cu cermet powders with thermal conductivity anisotropy by electroless deposition

Core-shell structured cermet powders with thermal conductivity anisotropy have been brought into focus because they have a great potential application as the horizontal thermal diffusion layer material in multilayer thermal protective coating (TPC). In this contribution, core-shell structured YSZ@Cu cermet powders were fabricated by electroless deposition (ED) of Cu on yttria-stabilised zirconia (YSZ) powder. The surface of YSZ powder was uniformly coated with a thin Cu shell of approximately 2 μm. Through X-ray photoelectron spectra (XPS) analysis, it was found that trace CuO and Cu₂O oxides formed on the surface of Cu shell. Results of thermal spraying adaptability analysis show the flowability of core-shell structured YSZ@Cu cermet powder improved to 56.8 s/50 g, which conforms better to the basic requirements of thermal spraying material. By differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests, the YSZ@Cu powder had good thermal stability. In particular, between 25 and 500 °C, the anisotropy thermal conductivity rose higher than 1.8 and it remained stable at approximately 1.6 with temperature as high as 900 °C. All these features promise it a high-performance thermal conductivity anisotropy material.