Kneading behaviour and homogeneity of zirconia feedstocks for micro-injection molding

This study used capillary rheometer, transmission optic microscopy (TOM) and torque rheometer to quantitatively analyze the homogeneity of zirconia feedstock and presents the report of the relationship between homogeneity and kneading parameters. The rheological indexes (αstv, Ha and Hz) of four feedstocks were determined by the capillary rheometer showing consistent results. The results of torque and kneading power input of the feedstocks showed consistent behavior with the microstructural parameter (dispersive index, Ds). This indicated that the Ds (=1−φa) could be used as a parameter for the improvement of the homogenous property of the feedstocks. The power consumption diagram (kneading power–Reynolds number, Np–Re′) calculated by several torque parameters reveals the critical issues related to the homogeneity of the feedstocks.