Additive Manufacturing of Si-SiC Cermets for Combustion Device Applications

Traditional manufacturing methods for high-temperature devices are time intensive and limited to simple shapes. Additive manufacturing (AM) reduces lead times and opens the design space to more complex geometries. Indirect laser sintering of siliconized silicon carbide (Si-SiC) cermets was evaluated for creating devices compatible with combustion environments. Heat recirculating combustors especially benefit from geometric flexibility. Si-SiC process improvements are presented for the production of cermet combustors. The effect of flame on the material was studied by directly exposing samples to hot combustion products at 1000°C and 1260°C for 10 hours. Subsequently, three experimental Si-SiC combustors were manufactured and fired to evaluate the practical aspects of cermet applications. Each device was operated for 70 hours under excess-air methane flames with solid temperatures up to 1405°C. The surface oxidation and phase changes were assessed. Operating temperatures between 1200°C and 1350°C reduce damage to the material and give a promise of long-term, high-temperature operation.