Effect of dispersant content and drying method on ZrO2@Al2O3 multiphase ceramic powders

ZrO2@Al2O3 composite ceramic powders were prepared by solution combustion method with aluminum nitrate (Al (NO3)3) and 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y- TZP) as the main raw materials, ammonium polyacrylate (PAA-NH4) as a dispersant, urea (CO (NH2)2) as a reducing agent. The effects of PAA-NH4 concentration and drying method on the microstructure and morphology of the ZrO2@Al2O3 powders were investigated. The results showed that when the concentration of PAA-NH4 was 1.5 wt%, and the molar ratio of Al (NO3)3 to CO (NH2)2 was 1:2, the ZrO2@Al2O3 powders with uniform grain size and high crystallinity could be synthesized by solution combustion drying method. Additionally, the abnormal growth of 3Y- TZP grain in ZrO2@Al2O3 was suppressed and the crystalline phase transformation trend (t-ZrO2 to m-ZrO2) was obviously decreased after sintering at 1600 °C.