Fabrication of mullite-bonded porous SiC using Ti3AlC2 MAX phase

Abstract

This study assessed the feasibility of a Ti3AlC2 MAX phase as an Al-source for the formation of a mullite bond in the fabrication of porous SiC tubes with high strength. The as-received Ti3AlC2 was partially oxidized at 1200°C for 30 min before using to minimize the abrupt volume expansion caused by oxidation during sintering. Thermal treatment at 1100-1400°C for 3 h in air led to the formation of Al2O3 by the decomposition of Ti3AlC2, which reacted further with oxidation-derived SiO2 on the SiC surface to form a mullite phase. The fabricated porous SiC tubes with a relative density of 48 – 62 % exhibited mechanical strengths of 80 – 200 MPa, which were much higher than those with the Al2O3 filler material. The high mechanical strength of the Ti3AlC2-added porous SiC was explained by the rigid mullite neck formation along with the retained Ti3AlC2 with good mechanical properties.