Effects of TMAH dispersant on rheological behavior of Nd: YAG slurries and optical properties of transparent ceramics

In this study, transparent Nd: YAG ceramic was fabricated by gel casting of iso bam system using a dispersant composed of tetramethylammonium hydroxide (TMAH) to modify the rheological properties of slurry. The effects of dispersant content on the dispersibility and viscosity of slurry were studied, as well as the microstructure and light transmittance of the obtained transparent ceramics were also analyzed through the introduction of 0 − 1.5 wt.% TMAH. The results showed that the dispersion mechanism of TMAH is mainly to control the electrostatic property and the alkaline Zeta potential value of the slurry. The electrostatic repulsion of ceramic particles in the slurry could be effectively increased through the dispersing action of the additive, thereby reducing the viscosity of the slurry and improving the fluidity of the slurries. Under the TMAH content of 1 wt.%, a high-fluidity and good dispersion of Nd: YAG slurry with a solid load of 78.8 wt.% was obtained. A low viscosity of 72.89 mPa·s was achieved under shearing of 100 s^-1, and a dense uniform body was obtained by self-gelling reaction. Highly transparent Nd: YAG ceramics were obtained after vacuum reaction sintering at 1780°C for 10 h, with a transmittance of 75.12% at 1064 nm. In all, the TMAH dispersant could effectively improve the molding properties of PIBM single system gel injection molding transparent ceramics.