Grain Coalescence and Modeling of Nanosized Zirconia in Solid-state Sintering

Abstract

In this research, 50nm 3 mol % Yttria Stabilized Zirconia powder (3Y-TZP) was selected to demonstrate the potential of injection molding micro features. The produced 3mm micro gear was visually defect-free with well defined gear teeth and achieving high hardness of 3Y-TZP. Sintering behavior of the nanosized powder was characterized and compared with the conventional coarse counterpart. It was found that the nanosized powder grew extensively during initial sintering stage, with an observation of irregular shaped grains. A grain coalescence dominated solid-state sintering model was proposed to be responsible for the extensive initial growth of nanosized powder. Coalescence of low angle grains is incorporated in phase field simulation and the simulated microstructural evolution and the relative growth have shown good agreement with the empirical findings. The results suggested that grain coalescence is an important growth means for nanosized powder, on top of curvature migration.