Dispersion of Zirconium Diboride in an Aqueous, High‐Solids Paste

Abstract

The dispersion of ZrB 2 particles was investigated. In aqueous systems, the surface of ZrB 2 consists of a thin layer of ZrO 2 that controls the surface chemistry and surface charge. Measurements showed that the ZrB 2 had an isoelectric point of pH=4.7 and a maximum ζ potential of −50 mV at pH=9. The addition of a dispersant, either an ionic ammonium polyacrylate or a nonionic alkoxylated polyether, increased the ζ potential of ZrB 2 by as much as 60 mV to −110 mV. Viscosity measurements were used to optimize dispersant concentrations. High‐solids loading (∼45 vol.% ZrB 2 ) aqueous pastes were prepared with two different dispersants. The pastes had viscosities of 40–50 Pa·s which was acceptable for extrusion, and were used to fabricate three‐dimensional components from ZrB 2 .