抄録
Dense mullite ceramics with fine grain were produced from the precursor powders prepared by mechanochemical mixing of fumed alumina and silica powders. The mixed powder had continuous and dense silica coating layer throughout on the alumina aggregates, which significantly improved dispersion stability and packing characteristics. Such a homogeneous coating of amorphous silica onto external and internal surfaces of fumed alumina enhanced densification as well as formation rates of mullite compared to heterocoagulated precursor powder. Silica deposition on the alumina powder by mechanochemical mixing resulted in increased silica connectivity and silica/alumina interface area. Fine-grained mullite of near full-density was obtained by sintering at 1600oC the samples, which increased the flexural strength up to 300 MPa.
