Effect of Pressurizing during Compaction and Sintering on the Formation of Reaction-Bonded SiC–Ti3SiC2

A reaction-bonded SiC-Ti3SiC2 ceramic composite was produced for use in a ceramic-metal composite cladding tube. The diffusion reaction between TiC and Si was investigated with respect to process pressure. The mole-fraction of TiC and Si was controlled to be 3:2 to obtain a Ti3SiC2 phase in the ceramic composite. Sintering was conducted at 1450 degrees C where TiC particles could react with melted Si. SiC ceramic composites consisting of Ti3SiC2 and TiSi2 matrix phases were obtained. The formation of the constituent phases was strongly related to the processing pressure. The number of second phases in the SiC-Ti3SiC2 composite was controlled by adjusting the processing pressure. When the powder compacts were not pressurized, no Ti3SiC2 phase was formed. However, the Ti3SiC2 phase was formed under pressurizing during compaction and/or sintering. The higher the pressure the higher the purity of SiC-Ti3SiC2. The dual-phased SiC-Ti3SiC2 composite, however, revealed the decreased resistance to high-temperature oxidation. It is suggested that the incorporation of TiSi2 in the composite increases the oxidation resistance as well as mechanical property.