Si‐rich pressureless sintering of the gelcasted Ti₃SiC₂ bulk ceramic

Abstract

The Si‐rich pressureless sintering was used to fabricate the Ti3SiC2 bulk ceramic. The results show that the optimized Ti3SiC2 suspension could be prepared at the absolute value of zeta potential, pH level, PAA‐NH4 dosage, and solid loading of 62.1 mV, 11, 2.0 wt%, and 50 vol%, respectively. The channels existing in the Si‐free sintered body facilitated the reactants and products to diffuse to the interior and out of the Ti3SiC2 matrix, thereby forming the porous reaction layer of TiC‐Ti3SiC2. The co‐effects of the channels and the reaction layer of TiC‐Ti3SiC2 severely lowered mechanical properties of the Si‐free sintered Ti3SiC2 ceramic. On the contrary, the Si‐rich sintering method isolated the volatile carbon and established a closed Si‐rich atmosphere to sinter the green Ti3SiC2 cylinder. The porosity, density, fracture toughness, hardness, and flexural strength of the Si‐rich sintered Ti3SiC2 ceramic reached 0.74 vol%, 4.36 g/cm3, 5.49 MPa·m1/2, 4.03 GPa, and 383 MPa, respectively.