Evaluation of aluminosilicate glass sintering during differential scanning calorimetry

The aim of this work is to investigate a difference in heat flow observed in the differential scanning calorimetry curves when aluminosilicate glasses are analyzed. Glasses with nominal composition 56.21 SiO2 18.65 Al2O3 25.14 MgO (wt%) were produced by the conventional melting process. Glass frits were milled and sieved in the range of 45–63 µm. The material was analyzed by X-ray fluorescence spectrometry, X-ray diffraction, differential scanning calorimetry (DSC), and differential thermal analyses (DTA). The particle size distribution was determined by laser diffraction technique. The microstructures of the samples were observed by scanning electron microscopy after removing them from the DSC sample holder. The density was determined by He picnometry. The difference in heat flow in the DSC curves is assigned to the sintering process occurring during the heating cycle, which was confirmed by the neck formation in the particle interface, DSC signal variation in isothermal measurements, no change in the heat flow when monolith specimen are analyzed, and in subsequent DSC analysis after cooling. The concurrent crystallization was also determined.