Effects of the Al content on pore structures of porous Ti3AlC2 ceramics by reactive synthesis

Porous Ti3AlC2 ceramics were fabricated through the reactive synthesis method with TiH2, Al and graphite powders. The effect of Al content on phase constitution, volume expansion, pore size and permeability were studied systematically. The experimental results showed that the Al content has a great affect on the properties and pore structures of porous Ti3AlC2 ceramics. When Al molar ratio was less than 1.2, the volume expansion ratio, the amount of Ti3AlC2 and porosity were improved with the increase in Al content. In contrary, these parameters of the porous Ti3AlC2 decreased while the Al molar ratio was more than 1.2. However, it was interesting to notice that the evolution of pore size and permeability was opposite to that of porosity. The fundamental reasons behind these phenomena have been explored. The pore structure forming mechanism by active sintering synthesis has also been proposed.