OXIDATION AND HOT CORROSION OF DUPONT LANXIDE ENHANCED SiC/SiC AND HITCO SiC/C COMPOSITES

摘要

A hot corrosion and oxidation study of SiC/SiC and SiC/C composites was conducted to examine environmentally induced interactions with the fiber and matrix and to assess the composite degradation in the simulated molten salt environment of a naval aircraft gas turbine engine. High temperature testing included both static and cyclic thermal exposures to 900 deg C in air for time intervals from 1 to 1000 hours. Composites were tested both as received and coated with a layer (0.5-1.0 mg/cc) of sodium sulfate. Microstructural analysis and weight change measurements were used to examine the degradation of the exposed composites and phase identification was performed with X-ray diffraction assisted by chemical analysis via Energy Dispersive X-ray Spectroscopy (EDS). Phase evolution and transformations were determined in-situ with the aid of a high temperature x-ray diffractometer. Degradation of these composites, being investigated for navy propulsion applications are characterized.