CRYSTALLIZATION OF INVISCID MELT-SPUN (IMS) CALCIA-ALUMINA (CA) EUTECTIC FIBERS

Crystallization behavior of vitreous calcia-alumina (CA) fibers of eut ectic composition (46.5 wt% CaO-53.5 wt% Al2O3) was studied by differe ntial thermal analysis (DTA), scanning electron microscopy (SEM) and X -ray diffraction (XRD). From DTA results, crystallization temperature of the CA fibers ranges from 948 to 1034 degrees C according to DTA he ating rates. The activation energy value for crystallization of the CA fibers was determined as 490 kJ/mol and 477 kJ/mol via Kissinger and Augis-Bennett methods, respectively. SEM for crystallized CA fibers sh owed surface roughness, whereas that for vitreous CA fibers showed typ ical glassy fracture. Wide angle X-ray diffractometer analysis on CA f ibers which were crystallized by the DTA scans showed Ca12Al14O33 form ation as a major phase and CaAl2O4 formation as a minor phase.