Physical Characteristics and Sintering Behavior of MgO-Doped ZrO2nanoparticles

Nanosized particles of 13mol% MgO-doped ZrO₂ with a narrow distribution of pore sizes were prepared by the coprecipitation technique using optimized parameters of synthesis. Transmission electron microscopy analysis of the calcined powder reveals that the majority of the particles have grain sizes in the 10–20nm range. From nitrogen adsorption analysis an average particle size of 13nm was estimated, which is similar to the average pore size diameter (12nm). Besides the unimodal distribution of pore sizes, the linear shrinkage curve of a powder compact exhibits several inflexions indicating different rates of densification up to 1600°C. After sintering at 1600°C for 2h, the microstructure features of a compact are characteristics of the intermediate stage with interconnected porosity preferentially observed at grain boundaries. These results are explained as a size effect of nanoparticles of magnesia-doped zirconia during sintering.