Fabrication of textured alumina-mullite-silicon carbide nano-composites

The controlled development of microstructure such as nanocomposite or texture is a way for effectively improving physical and mechanical properties, Al₂O₃-mullite-SiC nanocomposites were prepared by partial oxidation of the Al₂O₃-SiC green body followed by reaction sintering. Recently, we reported that the crystal orientation of alumina can be controlled in a high magnetic field due to its crystal magnetic anisotropy. By the combination of both techniques we have demonstrated that textured Al ₂O₃-mullite-SiC nanocomposites can be fabricated by slip casting of mixed suspensions of Al₂O₃ and SiC powders in a high magnetic field followed by partial oxidation and reaction sintering of the Al₂O₃ and SiC The sintered density depended on the degree of dispersion and oxidation of SiC Dense nanocomposites were prepared by suitable oxidation and reaction sintering at 1600 without pressure. The three-point bend strength was observed approximately 800 MPa for the nanocomposites. The strength depended on the textured plane and amount of mullite phase, and increased using the suspension treated by beads-milling due to the de-agglomeration of SiC powders.