Synthesis of Ti3(SnxAl1-x)C2 solid solutions over the whole composition range

The properties of MAX phases can be fine-tuned to meet some particular applications via solid solution route, and the feasible preparation of the MAX solid solutions is a prerequisite for their applications. Ti3(SnxAl1-x)C2 solid solutions over the whole composition range (x = 0-1) are synthesized by pressureless sintering, and characterized by XRD and SEM. The composition and crystal structure of representative Ti3Sn0.8Al0.2C2 are examined by HRTEM, HAADF and EDS associated with STEM, and thus the Sn-rich Ti3(SnxAl1-x)C2 solid solution is confirmed. Combined with means of thermal analysis, the reaction path for the formation of the Sn-rich Ti3(SnxAl1-x)C2 solid solution is explored. Solid solutions are found to form with TiC as the nucleus and grow by reacting with Ti-Sn/Ti-Al intermetallic compounds. This work proves that the Ti3(SnxAl1-x)C2 over the whole composition range, in particular, the Sn-rich end of this series of solid solutions can be obtained by the simple pressureless sintering, and would enable the fine manipulation of the composition of these typical MAX solid solutions for technologically important applications. (c) 2021 Elsevier B.V. All rights reserved.