Formation Mechanisms of Ti_3SnC_2 Nanolaminate Carbide Using Fe as Additive

摘要

Reactive sintering of 3Ti:Sn:2C and 3Ti:Sn:2C:0.6Fe powder mixtures is studied in the temperature range 510℃-1200℃ under argon. It is demonstrated that the recently discovered Ti_3SnC_2 phase is formed, provided that Fe is added to a 3Ti: Sn:2C reactant mixture within the synthesis conditions used. Using dilatometric and X-Ray diffraction analyses, the formation mechanism of Ti_3SnC_2 is discussed. Results show that at low temperature (about 510℃), tin is consumed to form Fe_xSn_y intermetallics. At high temperature (about 1060℃), tin is newly available to form Ti_3SnC_2 due to the melting of Fe_xSn_y. Then, the intermediate phases, TiC and Ti_2SnC, and/or Ti_5Sn_3, TiC, C, and Ti are dissolved in the (Fe + Sn) liquid phase and Ti_3SnC_2 very likely precipitate from the melt. The second part of the study deals with the optimization of the Fe content in the initial 3Ti:Sn:2C reactant powder mixture to synthesize samples with larger Ti_3SnC_2 content by hot isostatic pressing.