Effect of La2O3-CeO2 codoping on the microstructure and mechanical properties of tailing glass-ceramics

The effect of the La2O3-CeO2 content on the microstructure and mechanical properties of CaO-MgO-Al2O3-SiO2 tailing glass-ceramics codoped with La2O3 and CeO2 was investigated to gain insight into the properties of glass-ceramics produced from solid wastes. The results showed that augite was the dominant crystalline phase in all of the samples. Augite formed a solid solution phase containing La and Ce as the La2O3-CeO2 content increased, and the shape of the augite phases changed from dendritic to island-shaped because La oxyapatite precipitated at the augite boundary. Among the glass-ceramics, the highest percentage of Si-O tetrahedrons with two nonbridging oxygen atoms (Q2) was observed for that containing 1 wt% La2O3-CeO2. In addition, this particular composition exhibited an optimal microstructure owing to its high crystallinity and interlocking dendrites. Consequently, this microstructure displayed superior mechanical properties, such as Vickers hardness, bending strength, and fracture toughness of 7.95 GPa, 250.13 MPa, and 1.97 MPa/m1/2, respectively.