Effect of high-temperature oxidation on Si3N4 containing Ti3AlC2. Issue 10 (July 2020) - Liu, Jiongjie
Abstract: In this work, a dense Si3 N4 -based composite was fabricated by spark plasma sintering the mixture of Si3 N4 and Ti3 AlC2 . The nitrogen atoms of Si3 N4 diffused into the TiCx lattice and leaded to the in-situ formation of TiC0.3 N0.7 and SiC compounds. After annealing in air at 900 °C, TiC0.3 N0.7 was oxidized to form rutile-TiO2 particles (about 3–4 μm). Meanwhile, it was found that the oxidized composite displayed superior mechanical and tribological properties, compared to Si3 N4 and Si3 N4 -based composite before oxidation. Typically, the fracture toughness reached 9.97 MPa m 1/2, which was 59.5% higher than that of Si3 N4 . In addition to cracks branch, bridge and deflection, the surface barrier of oxides was another major toughening mechanism. Besides, due to the pinning effect of TiC0.3 N0.7, sliding-induced microcracks were completely suppressed, and the composite exhibited excellent friction and wear performances. In this case, the composite is expected to be fabricated into ceramic parts for service in high temperature environment.