The preparation of the lithium disilicate glass-ceramic with high translucency

To develop a lithium disilicate glass-ceramic with high translucency, the effects of the single-stage and two-stage heat treatments on the crystalline phases and microstructure of the Li2O-SiO2-Al2O3-K2O-P2O5 glass system were investigated. It was found that the nucleation of the two-stage treatment was more effective than that of the single-stage treatment, resulting in the smaller lithium disilicate crystals (referred as the LD hereafter). Besides, the size of the LD crystals increases with increasing the second heat treatment temperatures, so the second heat treatment temperature should be as lower as possible than the LD crystallization peak temperature on the premise that the LD is the main crystalline phase. Finally, the lithium disilicate glass-ceramic with the crystalline size of about 100 nm was developed, and the real in-line transmission (RIT) value was measured to reach 27.3% at the wavelength of 550 nm (d = 2.0 mm), which is much greater than that of the commercial lithium disilicate glass-ceramics.