Fabrication of Ti3SiC2-based composites from titania-silica raw material

We herein describe a two-step technique for fabrication of Ti3SiC2-TiC-SiC ceramic composites from leucoxene concentrate (LC). The proposed method involves vacuum carbothermal reduction of LC followed by hot pressing at 1450-1650 °C under 6.7 MPa. In the carbothermal stage, LC is converted into a weakly sintered product containing 68 vol.% Ti3SiC2, 31 vol.% TiC, and 1 vol.% SiC. In the next stage, this product is mixed with 5 vol.% elemental silicon and hot-pressed to fabricate a nearly fully dense composite. Flexural strength and fracture toughness of the sample prepared at 1650 °C reached 482 MPa and 5.39 MPa m½, respectively. The effects of preparation conditions on phase composition and characteristics of the ceramic composites are discussed.