Nickel assisted sintering of Ti3SiC2 powder under pressureless conditions

This investigation was aimed to study the effect of nickel addition on the sintering behaviour of Ti3SiC2 powder under pressureless conditions. Nearly pure bulk Ti3SiC2 ceramic with relative density of similar to 98.5% was produced at 1500 degrees C by sintering of Ti3SiC2 powder while using 1 wt.% nickel as a sintering aid. The activation energy of sintering of Ti3SiC2 powder was determined to be 351 +/- 5 kJ/mol, which was decreased slightly to 305 +/- 10 kJ/mol when nickel (1 wt.%) was added. Sintering of Ti3SiC2 powder was found to be controlled by mixed mode of mechanisms, i.e., the interface reactions and diffusion of Si atoms. The mechanism was changed to liquid phase sintering due to melting of Ni-based compounds in the sample sintered with Ni. The reaction of Ni with Ti3SiC2 helped to decrease the grain growth rate. The hardness (Vickers), flexural strength and fracture toughness of the sintered Ti3SiC2-1Ni sample were found to be 3.4 GPa, 311 +/- 22 MPa and 2.8-6.4 MPa m(1/2), respectively. (C) 2010 Elsevier B.V. All rights reserved.