Study On Preparation And Rheology Of High Solid Loading SiC Slurry

Modified coupling agent with styrene and maleic anhydride copolymers was synthesized by radical copolymerization. It was coated on the surface of SiC powders. Modified SiC powders with anhydride were prepared.Infrared Fourier transform spectrometry and Surface potential and particle size were used to analyse the surface characterization of SiC powders;Transmission electron microscopy was used to observe the morphology and dispersion of SiC powders;TG-DSC was used to analyse the thermal property and content of organic compound of modified SiC powders. Wetting, dispersion and rheological behavior were also studied in this paper.The results show that the characterization of SiC powders changed after modification. Copolymers with anhydride group were coated on the surface of SiC powders. The surface potential was also changed. The IEP of modified SiC powders shifted to acid region and the Zeta potential increased from -34.02mv to -48.54mv. The adding of dispersant TMAH can increase the Zeta potential of modified SiC powders. Wetting, dispersion and stabilization properties were largely increased. Before modification, the dispersion mechanism of SiC powders is electrostatic stabilization, while Electrostatic - steric Stabilization after modification.Controlling the factors effecting the rheological behavior, modified SiC slurry was prepared with solid loading of 58vol% and low viscosity when the proportion of WD-20 and SMA is 1:1, the content of modified agent is 1%, the pH value is 9 and the content of dispersant TMAH is 0.6wt%. Model fit of modified SiC slurries was studied. It shows that at low shear rate, the rheological curves of modified SiC slurries can fit well with Sisco model, comparing with Quemada model, Krieger-Dougherty model can fit much better with modified SiC slurries at high solid loading.