Engineering properties of aluminium titanate-mullite composites prepared by a gel coating powder processing

摘要

A gel coating powder processing method, namely a mullite precursor gel coating aluminium titanate powder (containing 2.5wt% MgO), was used to prepare various aluminium titanate-mullite composite powders. The effect of the composite composition onthe microstructure and on the mechanical and thermal properties was investigated. The results show an enhanced densification of the composite samples over the single phase aluminium titanate attributed to the effect of a liquid phase being present duringsintering. A microstructure with both acicular and equiaxed mullite grains was observed in the composite samples. Both the mechanical strength and thermal expansion coefficient increased with the mullite amount due to the progressively reduced crackdensity. The composite samples show a lower thermal shock resistance than that of the single phase aluminium titanate. The thermal stability of aluminium titanate is improved in the composite system.