Effect of Dispersant Concentration on Preparation of an Ultrahigh Density ZnO-Al_2O_3 Target by Slip Casting

摘要

The Theological behavior of concentrated ZnO-Al_2O_3 aqueous suspensions has been studied in order to obtain an ultrahigh-density ZnO-Al_2O_3 composite ceramic target by slip casting. The influence of the mass fraction of polyacrylic acid (PAA) on the fluidity of slurries and the density and strength of the green and sintered bodies was investigated. The slurries exhibited a near-Newtonian flow behavior and had a lower viscosity with 0.3 wt% PAA. The excess of PAA enhanced the green strength and the density and strength of the sintered bodies. An ultrahigh density sintered body (>99.7% theoretical density) could be obtained after pressureless sintering at 1400℃. The Al species were well distributed in the sintered bodies, which showed a homogeneous, defect-free microstructure with no abnormal grain growth.