Developing a liquid and curable two-component precursor system for fabrication of SiC(N)-based composites.

Precursor impregnation and pyrolysis (PIP) is an important process to fabricate fiber-reinforced SiC matrix composites, and a low viscous, curable, long-storable, and affordable liquid precursor is urgently needed. To meet the above requirements, a liquid two-component precursor system is proposed, which contains (1) the liquid by-product of polycarbosilane (b-PCS), and (2) organosilicon compound with double carbon bond. The b-PCS with the M ‾ w value of 635 is mainly composed of the oligomers of carbosilane with abundant amount of Si–H active groups. Four candidates of organosilicon compounds including tetramethyldivinyldisilazane (TMDS), methyltriallysilane (MTAS), Tetraallylsilane(TAS), and 1,3,5-Trivinyl-1,3,5-trimethylcyclotrisilazane (TVSN) were used, called crosslinkers. The effect of different crosslinkers on curing and pyrolysis process was investigated via TG-DSC, FTIR and TG-FTIR-MS, et al. Based on the results of the total ceramic yield, TVSN is the optimized crosslinker of four candidate organosilicon compounds. The ceramic product of corresponding two-component precursor was also characterized via element analysis, compositional element Si, C, N, and O account for 54.77 wt%, 36.23 wt%, 6.83 wt%, 2.07 wt%, respectively. Moreover, the two-component precursor has excellent storage stability at room temperature. [ABSTRACT FROM AUTHOR]