Abstract
The interaction of the SiC powder - polyacrylic acid (PAA, dispersant) - Y3+ ions (sintering additive) system was investigated in the pH range from 2 to 6. The amount of Y3+ ions adsorbed on SiC particles increased with an increase of pH because of the electrostatic attraction between negatively charged SiC surface and Y3+ ions. On the other hand, the amount of PAA adsorbed on SiC particles decreased with increasing pH because of the electrostatic repulsion between negatively charged SiC surface and dissociated PAA. The addition of PAA to the SiC suspension with Y3+ ions increased the amount of Y3+ ions fixed to SiC particles through the strong interaction between Y3+ ions and PAA adsorbed on SiC particles. The addition of PAA to the SiC suspensions with Y3+ ions kept the SiC particles separate during the calcination.
