INFLUENCE OF ZRO2 ADDITION ON MELTING KINETICS OF A YSIALO CLASS-CERAMIC

A ZrO2-free YSiAlO glass of composition 27Y: 42Si:31Al in equivalent % and one with the addition of 6 wt% ZrO2 were prepared in a nitrogen a tmosphere at 1700 degrees C. These glasses were treated in a nitrogen atmosphere at a controlled rare, during which the glass partially crys tallizes to form a glass-ceramic Under continued hearing melting occur s. This behaviour was monitored by differential thermal analysis, scan ning electron microscopy and X-ray diffraction. The original dendritic appearance of the crystallized microstructures changed to a blocky on e in the early stages of the melting process. The ZiO(2) addition was found to increase the kinetics of the phase transformations occurring during the melting. Copyright (C) 1996 Elsevier Science LTD