Translucent nano mullite based composite ceramic fabricated by spark plasma sintering

Dense translucent mullite-amorphous composite was fabricated from the metakaoline powder by spark plasma sintering, which was synthesized from halloysite powder mined in Algeria by annealing process. The dense sintered body with translucent could be formed by heating to 1300 degrees C at heating rate of 100 degrees C/min under applied pressure of 40 MPa and reducing atmosphere. The characterization was performed by X-ray diffraction analysis, TEM observation and ultraviolet spectroscopy. The result of X-ray diffraction analysis indicated that the mullite with crystallite size of 20-30 nm was precipitated into the dense sintered body during spark plasma sintering, which corresponded to the result of TEM observation. The result of ultraviolet spectroscopy indicated that this sample had translucence of 70-80% under wave length 1000 to 2500 nm.