Study on rheological properties of slurry of ZrO_2 matrix ceramics for gelcasting

The rheological properties of the slurry is the key of the gelcasting process of compound materials. The slurry needs high solid phase volume content and low viscosity. The exprement prepared ZrO_2-Al_2O_3 compound ceramic slurry by coating ZrO_2 powders with Al_2O_3. The research showed that the slurry is dispersed steadily through adjusting the pH value and dispersant. It was shown that when the pH is about 10 and the amont of dispersant is 3 percent by weight of powders, solid phase volume content of the slurry can reach 40 percent. It also showed that Al_2O_3 changes the character of the surface of ZrO_2, and improves stability of suspension.