Oxidation behavior of porous Ti3SiC2 prepared by reactive synthesis

High-purity porous Ti3SiC2 with a porosity of 54.3% was prepared by reactive synthesis and its oxidation behavior was evaluated under air in the temperature range from 400 to 1000 °C. Thermogravimetric analysis and differential scanning calorimetry (TG-DSC), scanning electron microscope (SEM), X-ray diffractometometry (XRD), energy dispersive spectrometer (EDS), Raman spectrum, BET surface area analysis, and pore-parameter testing were applied to the studies of the oxidation kinetics, phase composition, micro morphology, and porous structure parameters of porous Ti3SiC2 before and after oxidation. The results showed that the formation of TiO2 oxidized products with different modifications was the primary factor influencing the oxidation resistance and structural stability of porous Ti3SiC2. Cracks were observed in the samples oxidized in the full temperature range of 400-1000 °C because of the growth stress and thermal stress. At 400-600 °C, anomalous oxidation with higher kinetics and the aberrant decrement in pore size and permeability were attributed to the occurrence of severe cracking caused by the formation of anatase TiO2. At raised temperatures over 600 °C, the cracking phenomena were alleviated by the formation of rutile TiO2, but the outward growth of the oxide scales detrimentally decreased the connectivity of porous Ti3SiC2.