YSZ/Sm₂Zr₂O₇复合粉体制备及性能

Sm₂Zr₂O₇ (SZO) and Y₂O₃ partially stabilized ZrO₂ (YSZ) composite powders were prepared by agglomeration granulation after ball milling. The size, morphology and phase structure of granulated aggregates were characterized. The SZO/YSZ composite coating was prepared by atmospheric plasma. The effects of heat treatment and plasma spraying on the phase structure of composite powders and its phase stability were studied. The microstructures and phase structures of YSZ/SZO composite powders and coatings were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The stability of YSZ/SZO composite powders was investigated by differential scanning calorimetry (DSC). The results indicate that spherical agglomerated SZO and YSZ composite powders are relatively smooth and the structure is compact with a mixed phase structure at room temperature. No phase transformation occuring in the range of room temperature to 1200 °C reveals that the YSZ/SZO powders have suitability in the service temperature. The YSZ/SZO coating has a typical layered structure, and the composition and structure distribution of the coating are relatively uniform. Compared with the single SZO coating, the bonding strength of the YSZ/SZO coating is significantly improved. During plasma spraying, the stability of the powder decreases due to ions diffuse. The ordered phase in SZO transformed to disordered phase and the composite coating only presents a single fluorite structure.