THE EFFECT OF HIGH TEMPERATURE ON THE MICROSTRUCTURE AND PROPERTIES OF NICALON-REINFORCED ZIRCONIUM PHOSPHATE COMPOSITES

摘要

ZrP_2O_7 matrix composites reinforced with HVR Nicalon SiC fibers were thermally up shocked to temperatures up to 1400 deg C. Changes in mechanical (strength and toughness) and electrical (dielectric constant) properties were correlated with microstructural changes. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD) were used to microstructurally characterize the composites. ZrP_2O_7 composites can withstand thermal up shocking to 1000 deg C without any strength loss, while at temperatures of 1200 deg C and above the composite loses strength and toughness.