Powder Synthesis, Sintering Kinetics, and Nickel-Activated Pressureless Sintering of Ti3AlC2

초록

This work aims to produce Ti3AlC2 powder via a new route that consists of two-step processes, and studies the sintering kinetics and effect of nickel addition on the pressureless sintering behavior of Ti3AlC2 powder. Ti3AlC2 powder of about 5 mu m was produced using TiCx and Al powder. Relative density of about 97.6% was achieved using 1 wt% nickel as a sintering aid. Ti3AlC2 powder shows two different activation energies (AE) of sintering, 347 +/- 74 and 183 +/- 8kJ/mol at lower and higher temperature ranges, respectively. These AE were found to be matching closely with the AE of Al diffusion in the Ti-Al binary system reported in the literature, indicating that the sintering of ternary Ti3AlC2 ceramic was controlled by the diffusion of Al atoms. When nickel is added, Ni reacts with Ti3AlC2, tends to decompose it, and forms Ni-based compounds and liquid phase. Nickel was found to suppress the grain growth of Ti3AlC2 significantly. Sintered sample exhibited a Vickers hardness of 3.2 GPa at a load of 10 N.

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