Influence of ZrO2 addition on melting kinetics of a YSiAlO glass-ceramic

A ZrO2-free YSiAlO glass of composition 27Y: 42Si:31Al in equivalent % and one with the addition of wt% ZrO2 were prepared in a nitrogen atmosphere at 1700 °C. These glasses were treated in a nitrogen atmosphere at a controlled rate, during which the glass partially crystallizes to form a glass-ceramic. Under continued heating melting occurs. This behaviour was monitored by differential thermal analysis, scanning electron microscopy and X-ray diffraction. The original dendritic appearance of the crystallized microstructures changed to a blocky one in the early stages of the melting process. The ZrO2 addition was found to increase the kinetics of the phase transformations occurring during the melting.