Study on sintering and mechanical property of zirconia nano-powder TZ-3Y-E

Objectives: Various dental ceramics exhibit excellent aesthetic properties but low or moderate strengths. Yttria-stabilized-zirconia ceramics are amongst ceramics with high strength and fracture toughness. These are used for abutments, posts, implants and all-ceramic restorations, both single crowns and fixed partial dentures. The purpose of this study was to produce a new kind of yttria-zirconia ceramics with nano zirconia powder TZ-3Y-E, and to study its sintering and mechanical properties. Methods: Powder of TZ-3Y-E was pressed at 200MPa using cool isostatic pressing method and sintered at different temperature in air. Its sintered density was measured by Archimedes method. The flexural strength and fracture toughness was measured by three-point bend test and simple edge notched beam test respectively. Results: The result of the study indicated that with the rising of temperature, the sintered density and linear shrinkage increased. Sintered density of nano-powder zirconia was 6.09g/cm³ at 1300°C,and reached its ideal density. With the temperature increasing, the ceramic block density declined. Maximal linear shrinkage was 21.41% at 1300°C. The flexural strength and fracture toughness also increased with the rising of temperature, and reached to maximum value at 1536.37±85.49MPa and 5.07±1.34 MPa•m^1/2 at 1400°C respectively. With the temperature increasing, the value of three-point flexural strength and fracture toughness declined. Conclusions: Nano zirconia powder TZ-3Y-E can be sintered at low temperature(1300°C). Its mechanical property was perfect. The maximum value of three-point flexural strength and toughness was presented at 1400°C. It is a promising aesthetic all-ceramic dental material.