Synthesis and sintering of Ti3GeC2 MAX phase powders

Abstract

Ti3GeC2 is one of the potential MAX phase compounds, for which, production and processing methods are yet to be optimized. There are very few reports on the synthesis of this compound, which are mostly in bulk form and contain large impurities. Present investigation attempts to synthesize Ti3GeC2 powder with improved phase purity and to understand phase evolution sequences. Synthesis was characterized as a liquid-solid reaction process; initiated after melting of Ge particles. At low temperature (~1200°C), yield was found to be very low, and the product had several intermetallics and carbides. At relatively higher temperature (at 1500°C), the conversion was found to be very high and particles were mostly finer than 10µm. Phase purity was further increased (over 96wt%) during sintering stage, as observed through x-ray diffraction analysis where impurity peaks were very small. Ti3GeC2 powder was found to exhibit poor densification behavior during pressureless sintering; however, it showed slow grain growth characteristics too, a highly desired feature for structural applications.