SiC-Si sub 3 N sub 4 bonded materials by the nitridation of SiC and talc

Silicon carbide-based materials are used in many applications due to their good thermo-mechanical properties at high temperatures. The nitrogenous bond formed from nitriding reactions of silicate minerals seems to be an interesting method to obtain these materials. In this work, the reaction of SiC with talc and N sub 2 atmosphere is studied. Pellets and/or bars of SiC-talc mixtures were reacted within the range 1395-1650 deg C. Reaction products were studied through XRD, textural properties, bending strength and microscopy. Reactions and mechanisms for this system are proposed. Silicon nitride is formed as principal bond phase. During reaction, volatilization of Mg takes place, where its loss is favoured at high temperatures and high N sub 2 flow rates. A loss of SiO(g) is also observed. Mechanical strength has a linear relation with the bond phase content.