Combustion synthesis of SiC-MoSi2-Al2O3 composites

Combustion synthesis of SiC-MoSi2-Al2O3 composites by using highly exothermic reactive system of MoO3-Al-Si-SiO2 was investigated. It has been shown that, by using the combustion synthesis method, it is feasible to prepare, at 1500 degrees C, an electrical heating element with room temperature resistivity and element watt loading of 12 Omega cm and 20 W/cm(2) respectively. The colloid containing nano -sized material 30 wt% SiO2, was used as the plasticizer medium as well as combustion source. The beta-SiC functioned as a filler material to control the combustion reaction and also constituted part of the final product. The amount of SiC additive varied in the range from 45% to 65% wt. and was optimized with respect to porosity level, reaction conversion and net-shape quality of the heating elements. The element containing about 60% wt. SiC reveals low porosity level, with full conversion for the reaction and superior net -shape quality. However, despite the relatively high level of porosity present in the final synthesized product, it can be used as an electrical heating element in accordance with the investigation at the element temperatures up to 1500 degrees C.