Influence of sintering environment on the spark plasma sintering of Maxthal 312 (nominally-Ti3SiC2) and the role of powder particle size on densification

Herein, we report on the synthesis of Ti3SiC2 via the Maxthal 312 (nominally-Ti3SiC2) commercial powder route using spark plasma sintering (SPS). The SPSed bulk samples contained ancillary phases (TiCx and TiSi2) irrespective of the sintering environment as confirmed by XRD phase analysis. The optimum sintering temperature below which intrinsic decomposition starts appears to be similar to 1350 degrees C in vacuum and similar to 1450 degrees C in argon atmosphere, respectively. The role of powder particle size on densification during spark plasma sintering (SPS) was investigated. Analysis of the SPS processing parameters (piston movement and piston speed) indicated that the densification of Maxthal 312 powder (nominally-Ti3SiC2) can be improved by reduction in particle size, thus promoting the Joule effect, necking, mechanical movement of particles and plastic deformation. Further investigation on the role of graphite heating element as well as environment during the SPS synthesis showed that the graphite paper employed during SPS as well as possible silicon loss during vacuum sintering were responsible for the decomposition at temperature below the melting point of Si and/or shifting of the resultant bulk sample composition away from monolithic phase. (C) 2019 Elsevier B.V. All rights reserved.