Investigation of the effect of various parameters on the amount and morphology of nano-laminate MAX phase in Cf-C-SiC-Ti3SiC2 composite

This research focuses on investigating the synthesis of nano-laminate Ti3SiC2 and evaluates the effect of various parameters such as the amount and size of TiC, residual silicon, aluminum additive and annealing duration on the amount and morphology of MAX phase in Cf-C-SiC-Ti3SiC2 composite fabricated by LSI method. The infiltration process conducted at a temperature of 1500 °C for 30 min and then the samples were annealed at 1350 °C. The phase composition and microstructure of the samples were analyzed by X-ray diffraction (XRD) technique and were observed by scanning electron microscopy (SEM), respectively. The results showed that by changing the TiC/polymer precursor ratio and TiC particles size, MAX phase content varied from 0 to 31 vol%. The highest amount of MAX phase (31 vol%) was synthesized in the sample which contains 0.13 g Al, a TiC/polymer precursor ratio of 4, TiC grain size of 2-3 μm and an annealing duration of 1.5 h. Removal of aluminum and presence of residual silicon led to the reduction of the MAX phase content down to 19 vol%. Microstructure observations indicated that MAX phases have been synthesized in the plate-like shape and equiaxial grains. They also revealed that the average distance between the layers, the average size of basal planes ({002}) and the average size of Ti3SiC2 in Z axis are dependent on the amount of residual silicon, the size of TiC particles and the existence of the aluminum in the initial composition.