FIGURE 3.

Toughening ceramics by coating, chemical and thermal surface treatments. (A) Monoclinic ZrO₂ and SiO₂ particle coating, toughening highly translucent ZrO₂. (a–d) scanning electron micrographs, (e–h) Zr and Si elemental mapping of samples coated with mZrO₂/SiO₂ and heat treated at 1,500°C (Uno et al., 2020). (B) Ion-exchange toughened lithium disilicate glass-ceramic. Changing tendencies of VIF toughness of the glass-ceramic with increasing (a) the ion-exchange time and (b) the depth of Li⁺/Na⁺ exchange obtained, at 450, 385 and 315°C, respectively, in a pure NaNO₃ bath (Li et al., 2020). (C) Scanning electron microscope fractographs of the lithium disilicate glass-ceramic: (a,c) in annealing state; (b,d) tempered in 250°C silicone oil. Reproduced with permission from Li et al. (2021). VIF, Vickers indentation fracture.