Achieving robust mechanical properties and high translucence in ZrO2–SiO2–Al2O3 ternary ceramic nanocomposites

Transparent or translucent ceramics typically exhibit inferior mechanical performance, which restricts their wider application. Here, we aim to develop ZrO 2 –SiO 2 –Al 2 O 3 ternary ceramic nanocomposites (TCNCs) that integrate those two often incompatible properties via microstructure engineering. A fixed ratio of 30 mol% SiO 2 was introduced into the ZrO 2 –Al 2 O 3 system, while the ratios between ZrO 2 and Al 2 O 3 were varied. Additionally, different forms of Al 2 O 3 (crystallization or amorphous) were used, resulting in four types of TCNCs. Among the samples studied, the TCNC containing 60 mol% ZrO 2 and 10 mol% amorphous Al 2 O 3 achieved high translucency and remarkable mechanical properties. The TCNC comprised ZrO 2 nanoparticles embedded in SiO 2 glass matrix and Al 2 O 3 glass domains. The superior properties of the TCNC can be attributed to its nanocrystalline-amorphous dual-phase microstructure. For TCNCs utilizing α-Al 2 O 3 submicron particles as the aluminum source, despite their adequate mechanical properties, the agglomeration and lack of densification of these particles resulted in significant light scattering, rending the TCNCs opaque. This study demonstrates that engineering a nanocrystalline-amorphous dual-phase microstructure is an effective strategy to achieve a synergistic combination of robust mechanical properties and high translucence.