WEB Ablation Behaviour of SiB(O)NC Ceramic Foams Derived from Boron Modified Cyclotrisilazane for High Temperature ApplicationsThursday (24.09.2020) 11:50 - 12:05 Z: Special Symposia I Part of:
In our previous work , a simple and low-cost synthetic route utilizing boron modified cyclotrisilazane (BCTS) as preceramic polymer was reported for preparation of SiBCN ceramic. BCTS resin demonstrated the desirable properties required for preceramic polymers such as solubility in common solvents, processable viscosity (< 19 cps) and high ceramic yield (> 75 wt. %). The pyrolysis of BCTS under nitrogen atmosphere yielded SiB(O)CN ceramics. Based on the promising results obtained with SiB(O)CN ceramics, in the present study SiB(O)CN ceramic foam is prepared using BCTS as preceramic resin and poly(methyl methacrylate) as sacrificial template. The X-ray computed tomography of SiB(O)CN ceramic foam revealed the existence of both closed and open porosity. The high temperature performance of the fabricated foam was evaluated using ablation resistance test at 1500°C for various time (30s, 90s and 270s) using an oxyacetylene flame. The SiB(O)CN ceramic foam displayed very low mass ablation and linear ablation rates as compared to boron-free SiC and SiCN systems reported in literature. X-ray diffraction and scanning electron microscopy analyses of ablated SiB(O)CN ceramic foam revealed the formation of β-SiC and SiO2 as ceramic phases indicating that the thermal stability of SiB(O)CN ceramic foam is due to the formation of a thin protective SiO2 layer. This study demonstrated the applicability of BCTS route derived SiB(O)CN ceramic foam as a thermal protection material for high temperature applications.