Development of High Temperature Carbon-Silicide-Carbide Composites via Reactive Melt Infiltration
The development of a silicide-carbide composite using melt infiltration technique was investigated. A carbon fiber preform was infiltrated with an alloyed melt of Si, Ti and MoSi2. In order to prevent the melt from reacting heavily with the fibers and keep a weakly bonded interface, the temperature of the melt was reduced to 1600 °C by adding Si and Ti to MoSi2. The infiltrated samples were studied using XRD, SEM and DTA techniques. SiC was shown to be the major phase in the matrix. MoSi2 and solid solutions of Si, Mo and Ti could also be found in the matrix. Under optimised conditions, composites without residual silicon could be obtained. Bending strength, and creep resistance of resulted composites were measured and compared with silicon-infiltrated samples. At room temperature and also at 1600 °C the strength of C/C-composites was higher than infiltrated felts. Similarly the alloyed-melt-infiltrated felts showed higher strength than silicon-infiltrated felts. C/C composites showed only marginal creep while the felt composites underwent considerable deformation at 1600 °C.