بررسي رفتار كريستاليزاسيون الياف ژله اي آلومينا-ايتريا عمليات حرارتي شده در دماهاي مختلف

Characterization of crystallization behavior of alumina-yttria gel fibers heat treated at various temperature

Continuous-fibers have different applications for manufacturing of high performance and high temperature composites. Various methods are used to make ceramic fibers. In this research, composite fibers (YAG/A1203) were prepared by a sol-gel method using aqueous solution. They were synthesized from aluminum salt, aluminum metal, yttrium oxide and water used as solvent. Transparent gel fibers were obtained by immersing a thin wire into the viscous sol, then pulling it out by hand. The influence of heat treatment on crystallization and phase transformation of the dried gel was investigated using X-ray diffractometery (XRD), scanning electron microscopy (SEM), thermogravimetry and differential thermal analysis (TG-DTA). It was shown that crystallization of YAG and alpha alumina phases was started at 1100°C and completed at 1400 °C. The ceramic composite fibers had fine microstructure (100-200 nm) after heat treatment.