Enhanced performance of low-pressure sintered CaO–MgO–Al2O3–SiO2–CaCl2 glass-ceramic by using Cr2O3 as the nucleating agent

The sintered glass-ceramic always has an uneven microstructure due to the surface crystallization, which limits the enhancement of its mechanical properties. In the present work, Cr2O3 was added into CaO–MgO–Al2O3–SiO2–CaCl2 glass as the nucleating agent, and the low-pressure (14 kPa) sintering technology was utilized to promote the densification process of the glass frits (0.42–2 mm). It was found that by adding 1 wt% of Cr2O3, the bulk crystallization can be achieved inside the glass particle and the microstructure of the glass-ceramic became more homogeneous. Correspondingly, the bending strength was improved from 127 to 147 MPa, and the Vickers hardness was enhanced from 6.5 to 6.7 GPa, comparing with the Cr2O3-free glass-ceramic. The current study confirmed the positive impact of nucleating agent in the performance of sintered glass-ceramic, which also provided a route for the utilizations of CaCl2-and Cr2O3-bearing wastes.