Growth of lamellar Ti3SiC2 in SiC matrix by the reaction of Si melt with C-TiC preform

Abstract

The SiC-Ti3SiC2 matrix herein was prepared in situ by the melt infiltration (MI) method. The effects of the infiltration temperature and TiC content on the formation of Ti3SiC2 in the SiC matrix were investigated. The mechanism for Ti3SiC2 growth in SiC matrix was determined by investigating the infiltration path of the molten Si into the C-TiC preform. It was found that the Ti3SiC2 phase was mainly formed when the mass ratio of TiC to phenolic resin reached to 2.2, and upon infiltration at 1430 °C for 30 min. It was also demonstrated that the process of molten Si infiltrating into the C-TiC preform occurred through complicated chemical reactions and multicomponent diffusions. The phases of SiC and TiSi2 were preferentially formed during Si melt infiltration. A liquid Ti-Si eutectic appeared upon exceeding the Si-TiSi2 eutectic temperature. Ti3SiC2 was nucleated from the reaction between the TiC and liquid Ti-Si eutectic. The TiSi2 phase was precipitated from the liquid Ti-Si eutectic in the Si region during the cooling process. Moreover, the dissociative SiC grains in the Si region were also produced by the precipitation from the dissolution of the solid C in the liquid Si.