Fabrication of Ti ₃ SiC ₂ ‐Ti ₄ SiC ₃ ‐SiC ceramic composites through carbosilicothermic reduction of TiO ₂

Abstract

Abstract Dense Ti 3 SiC 2 ‐SiC, Ti 4 SiC 3 ‐SiC, and Ti 3 SiC 2 ‐Ti 4 SiC 3 ‐SiC ceramic composites were fabricated through carbosilicothermic reduction of TiO 2 under vacuum, followed by hot pressing of the as‐synthesized products under 25 MPa at 1600°C. In the reduction step, SiC either alone or in combination with elemental Si was used as a reductant. A one‐third excess of SiC was added in the reaction mixtures in order to ensure the presence of approximately 30 vol.% SiC in the products of synthesis. During the hot pressing step, the samples that contained Ti 3 SiC 2 showed better densification compared to those containing Ti 4 SiC 3 . The obtained composites exhibited the strength properties typical of coarse‐grained MAX‐phase ceramics. The flexural strength values of 424 and 321 MPa were achieved in Ti 3 SiC 2 ‐SiC, and Ti 3 SiC 2 ‐Ti 4 SiC 3 ‐SiC composites, respectively. The fracture toughness values were 5.7 MPa·m 1/2 .