Synthesis and oxidation resistance of different Ti3SiC2–TiC composites

Abstract

Preparation of Ti3SiC2–TiC composite from TiC, SiC, and Ti was performed using Spark Plasma Sintering (SPS). Initial powders were mixed using a planetary ball mill for 2 h with 90 RPM. The number of milling media was varied to obtain the best homogeneity of the samples between 70 and 250. SPS was performed at 1450, 1550, and 1600 °C in Ar and vacuum. By decreasing the amount of TiC in the initial mixture unreacted Ti5Si3 appeared in the final composition. Samples were subjected to 10 h oxidation tests at 900, 1000, and 1100 °C using thermogravimetry. The ideal sintering regime (highest oxidation resistance) was found to be 1550 °C with 10 min dwell time in Ar atmosphere. Oxidation kinetics of the prepared compacts was found to be following the parabolic law. The lowest overall oxidation rate was observed for the samples with the highest (above 87 wt%) Ti3SiC2 content. On the other hand, sample with Al addition was the most prone to oxidation. The phase composition of the samples played a higher role in their oxidation behaviour than their porosities.