Electric Current-Assisted Synthesis of the Ti2AlC MAX Carbide Phase by Arc Melting and Heat Treatment Using Spark Plasma Sintering

Herein, two current-assisted techniques, arc melting and spark plasma sintering (SPS), are investigated for the synthesis of the Ti2AlC carbide MAX phase. Synthesis parameters are adjusted to improve the composition of the samples and limit the proportion of secondary phases. A 3 min heating at low power (15% of the maximum current of 180 A) on the arc melting furnace leads to a sample containing more than 71 wt% of Ti2AlC. The impact of parameters such as time, power, and generator amperage is considered. By SPS, a two-step cycle is used to ensure the formation of the titanium aluminide compounds before reaching higher temperatures. A first dwell at 600 degrees C for 15 min and a second dwell at 1200 degrees C for 10 min, under a load of 75 MPa, leads to a sample containing more than 85 wt% of Ti2AlC. Without pressure, a single-phase Ti2AlC sample is obtained. It is found that the application of a load is not beneficial to the formation of Ti2AlC but shifts the composition toward the formation of Ti3AlC2. The composition of this sample is further investigated by energy-dispersive X-ray spectroscopy (EDXS) and wavelength-dispersive X-ray fluorescence (WDXRF) to check the presence of impurities.