Synthesis reactions of Cr2AlC from Cr-Al4C3-C by pulse discharge sintering

The reaction process of ternary compound Cr₂AlC synthesis was studied. Powder mixture of Cr, Al₄C₃ and graphite at the composition of Cr:Al:C = 2:1.1:1 was processed by pulse discharge sintering in vacuum in the temperature range of 850 to 1350 °C. The synthesized materials were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with an energy dispersive spectrum (EDS) system. It was found that the amount of Cr₂AlC phase increased significantly in the temperature range of 950 to 1150 °C at the consumption of Cr and Al₄C₃ as well as an intermediate phase Cr₂Al. Predominantly single-phase Cr₂AlC with small amount of Cr₇C₃ was obtained as the sintering temperature is above 1250 °C. It is presumed that Cr₂AlC phase is formed near Al₄C₃ particle by the diffusion of Cr and the reaction of the diffused Cr with Al₄C₃.