Influence of Cr2O3, LiF, CaF2 and TiO2 nucleants on the crystallization behavior and microstructure of glass-ceramics based on blast-furnace slag

Glass-ceramics based on blast-furnace slag (56.78 wt%) were prepared by mixing quartz sand, dolomite, limestone, clay as other batch constituents.The nucleating agents Cr2O3, LiF, CaF2 and TiO2 were added to the batches to study their effects on the crystallization, phase assemblages, and microstructure. Glass-ceramics were obtained by single and double heat-treatment schedules and examined by DTA, XRD and polarizing microscope. The presence of Cr2O3, TiO2, CaF2 and LiF was found to enhance the crystallizability of the glass. Cr2O3 and TiO2 are much better than LiF and CaF2 in promoting homogeneous nucleation and the formation of extremely fine-grained microstructure of aluminous pyroxene and magnetite.