Polyacrylic acid, a highly efficient dispersant for aqueous processing of tantalum carbide

Polyacrylic acid (PAA) with three different molecular weights (PAA-3000, PAA-15000, PAA-100000) was used as a dispersant to investigate the aqueous dispersion behavior of commercially available TaC powder. TaC stabilized with PAA-3000 polymer showed the best dispersion behavior according to zeta potential and rheological measurements. In addition, the TaC slurry in the presence of PAA-3000 had a minimized average particle size of merely 1.08 µm when dispersed in alkaline aqueous solutions. This was effective to break down any original agglomerates. A characteristic carboxylic peak was detected after adding PAA-3000 to the aqueous TaC system, using XPS analysis. Our TEM results confirmed that the surface properties of TaC were modified by the PAA-3000 dispersant. The slip-cast green body exhibits enhanced homogeneity compared to its dry-pressed counterpart. A dense TaC monolithic ceramic (>99%) was obtained after sintering. This study contributes to the understanding of advanced wet-forming techniques for TaC ceramics.