Raction synthesis of AIN-TiC ceramic and mechanism of densification

Compact AIN-TiC ceramics were fabricated by combustion synthesis of Al particles in super-high pressure nitrogen (100MPa), and the maximal relative density of 95% can be gained in the products, and maximal bending strength reached 240 MPa. In the SHS process of Al-N₂-TiC system, when the temperature was up to 660°C, Al melted. At high temperature of SHS reaction melting, Al spread over TiC particle surfaces, which led to liquid sinter occur in the SHS reaction zone. With liquid sinter occurred, the porosity of reaction zone apparently decreased. With increasing of TiC content in the original powder system, liquid sintering strengthened, and relative density of the products improved, bending strength and fracture toughness increased. In Al-Na-TiC system, SHS-densification had apparent tropism, mainly occurred along the combustion front.