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

Abstract 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.