Preparation of CaO-MgO-Al2O3-SiO2 glass-ceramic with a high content of Cr2O3 using the spark plasma sintering (SPS).

• CaO-MgO-Al 2 O 3 -SiO 2 glass-ceramic with high contents of Cr2O 3 was investigated. • The glass-ceramic was prepared by SPS and showed bulk crystallization behavior. • Coarse spinel crystals resulted in intergranular fracture and effectively hindered crack propagation. • The glass-ceramic showed high bending strength and vickers hardness of 214 MPa and 8.2 GPa, respectively. 2, 6, or 10 wt% of Cr 2 O 3 was added into the CaO-MgO-Al 2 O 3 -SiO 2 precursor glasses (PG), aiming to investigate the effects of high contents of Cr 2 O 3 on the crystallization behavior and mechanical properties of glass-ceramics (GCs). The PGs were milled into powder and then sintered by spark plasma sintering (SPS) technology at 750∼850 °C under the pressure of 10 MPa. It was found that Cr 2 O 3 induced the precipitation of spinel nuclei in the PGs, which served as the heterogeneous nucleation sites for the augite crystals. Augite and spinel were the main phases of the GCs, and the crystallinity increased by increasing the Cr 2 O 3 addition amount and sintering temperature. The GC prepared at 850 °C with 6 wt% Cr 2 O 3 addition showed excellent bending strength, with Vickers hardness, and fracture toughness of 214 MPa, 8.2 GPa, and 1.3 MPa·m1/2, respectively. [ABSTRACT FROM AUTHOR]