Manufacturing, characterization and testing of novel temperature-resistant nozzle structures based on liquid silicon infiltration

Kurzfassung

Ceramic matrix composites (CMCs) are considered as the most promising materials to replace super alloys in common rocket propulsion systems due to their excellent mechanical and thermal properties at high temperatures and low material densities. To demonstrate the capabilities of CMCs, a test campaign for new upper stage propulsion systems were performed at the DLR Institute of Space Propulsion in Lampoldshausen including a novel uncooled C/C-SiC nozzle extension. The green body was produced by wet filament winding. Following the preform was ceramized to the C/C-SiC state via liquid silicon infiltration. Since delaminations are a major concern of wound CMCs structures, the multi angle fiber architecture, which was used here, mitigates this risk. Computer tomography scans, which were carried out at all stages of the processing, show the changes of the component through each step. Furthermore, the quality of the material formed was determined by microstructure analysis using SEM. The structural integrity and thermal stability were tested by hot gas firing tests under laminar and separated flow conditions. The test proved that the ceramic nozzle shows the advantages of the high mass specific characteristic values and a sufficient high temperature resistance under extreme conditions.