Synthesis of aluminum nitride-silicon carbide solid solutions by combustion nitridation

AIN-SiC solid solutions were synthesized via a combustion nitridation proce ss. Reactions between powder mixtures of aluminum, silicon, and carbon or a luminum with beta-SiC and gaseous nitrogen under pressures of 0.1-8.0 MPa a re self-sustaining once they have been initiated. Investigations were made with reactant ratios of Al:Si:C = 7:3:3, 6:4:4, and 5:5:5 and Al:Si:C = 7:3 , 6:4, and 5:5, For the AI-Si-C system (molar ratio of 6:4:4), the maximum combustion temperature was dependent on the nitrogen pressure, increasing f rom 2300 degrees C to 2480 degrees C with an increase in pressure, from 0.1 MPa to 6.0 MPa, In all cases, the product contained the solid solution as the primary phase, with minor amounts of silicon. The amount of unreacted s ilicon decreased as the nitrogen pressure increased; the presence and depen dence of unreacted silicon on pressure has been explained in terms of the v olatilization of aluminum. The full width at half maximum for the (110) pea k of the AIN-SiC solid solution decreased as the nitrogen pressure increase d, which indicated the formation of a more homogeneous product.