Preparation of Li2Si2O5 fibers and their toughening effects on lithium disilicate glass-ceramics

To address the challenge of poor fracture toughness of lithium disilicate glass-ceramics, which hinders their application as posterior single crowns and three-unit fixed bridges, the concept of fiber toughening was employed. In this study, Li2Si2O5 fibers were successfully prepared through an electrospinning technology combined with sol-gel followed by a heat treatment. The fibers could be further densified by adding SiO2 nano-powder to partially replace TEOS as a silicon source and the possible mechanism was put forward. By using the fibers as the reinforcement phase, the uniform fiber-toughened Li2Si2O5 glass-ceramic composites were successfully produced by hot pressing sintering. These composites exhibited significant enhancements in mechanical properties, including a flexural strength of 315 ± 10 MPa, fracture toughness of 4.57 ± 0.35 MPa m1/2, and Vickers hardness of 5.61 ± 0.28 GPa, respectively. Notably, the highest fracture toughness of the composite increased by 41 % compared to the samples without fiber reinforcement, which was attributed to the toughening mechanisms including crack deflection, fiber bridging, and fiber pull-out. The results demonstrated the advantages of Li2Si2O5 fibers in toughening glass-ceramic materials, thereby expanding the application areas of this material.