Design and reinforcement mechanisms of the blue dual-phase zirconia ceramics with excellent mechanical properties

In this study, the NiAl2O4 was introduced as the second phase into 12 mol% cerium oxide-stabilized tetragonal zirconia polycrystal (12Ce-TZP) to obtain zirconia ceramics with excellent mechanical properties. The influence of NiAl2O4 on the microstructure, mechanical properties, and color performance of 12Ce-TZP were investigated. 12Ce-TZP-xNiAl2O4 was synthesized via the solid-state reaction method at 1500 degrees C for 3 h. The incorporation of NiAl2O4 led to the formation of a secondary phase and a decrease in grain size. Additionally, the precipitated NiAl2O4 was observed to adhere to the grain boundary surfaces. Due to the reduction in grain size and the exceptional mechanical properties of the spinel, the hardness of the ceramic increased, whereas its fracture toughness experienced a slight decrease, the slight decrease in fracture toughness is attributed to the reduction in phase variables, but it remains essentially unchanged. The coloration shifted from light yellow to blue in the ceramic. At a doping level of 20 % NiAl2O4, the deficiency in hardness inherent to 12Ce-TZP was ameliorated while preserving high fracture toughness, the optimal Vickers hardness and fracture toughness values reaching 12.4 GPa and 14.2 MPa & sdot;m1/2, culminating in the production of a blue zirconia ceramic characterized by uniform coloration and exceptional mechanical properties. These blue zirconia ceramics are applicable across various fields, including use as back panels in mobile phones.