Effect of 2‐Phosphonobutane‐1,2,4‐tricarboxylic Acid Adsorption on the Stability and Rheological Properties of Aqueous Nanosized 3‐mol%‐Yttria‐Stabilized Tetragonal‐Zirconia Polycrystal Suspensions

Abstract

2‐phosphonobutane‐1,2,4‐tricarboxylic acid (PBTCA) was evaluated as a dispersant for nanosized 3‐mol%‐Y2O3‐stabilized tetragonal‐ZrO2 polycrystal (3Y‐TZP) suspensions. The adsorption of PBTCA was characterized using the decolorization method of ferric 5‐nitrosalicylate complexes. Maximum adsorption of the dispersant on the 3Y‐TZP powder was found to occur at pH 3.0. At pH >3.0, the adsorbed amount decreased with increased pH. Semiquantitative analysis using auger electron spectroscopy showed that PBTCA adsorbed irreversibly on the powder. The surface charge of the powder was evaluated by measuring the zeta‐potential in dilute powder suspensions. The suspension was most effectively stabilized at high pH by the high charge induced by the adsorption of PBTCA. Rheological properties of the suspension were evaluated as a function of dispersant amount and solids loading. The optimum amount of dispersant increased with increased solids loading for solids loading >20 vol%. A stable suspension of 35 nm 3Y‐TZP particles with a solids loading as high as 32 vol% was obtained using PBTCA as dispersant, in contrast to 28 vol% when using ammonium polyacrylate (NH4PAA). Theoretical calculations of the interaction between 3Y‐TZP particles showed that the stabilization of the suspensions was attributed to a combination of the electrostatic repulsion and a steric barrier caused by the adsorbed PBTCA. Induced coupling plasma analysis showed that PBTCA could be completely burned out during sintering, which confirmed its suitability as a dispersant for 3Y‐TZP.

Rheology of Concentrated Suspensions Containing Weakly Attractive Alumina Nanoparticles

“…However, the processing of suspensions containing nanoparticles might be a quite challenging task, particularly in those applications that require a high volume fraction of solids, such as in the fabrication of thick dense films, near‐net‐shape components, and in ink‐jet technology. Although solids contents as high as 60 vol% can be easily achieved with conventional micro‐sized particles, reasonably fluid suspensions containing nanoparticles (particle diameter, d <70 nm) at concentrations higher than ∼40 vol% have not been reported 4–8 …”

Coagulation of Concentrated Suspensions of Ultrafine Alumina Powders by pH Shift

“…Solutions of NaOH (1 M ) and HCl (1 M ) are used as titrants. The use of PBTCA to disperse alumina suspensions has already been introduced in previous papers 12–15 . It is nevertheless necessary to determine the role of each functional group of the dispersant (i.e., carboxylate and phosphonate groups).…”

“…The use of PBTCA to disperse alumina suspensions has already been introduced in previous papers. [12][13][14][15] It is nevertheless necessary to determine the role of each functional group of the dispersant (i.e., carboxylate and phosphonate groups). With this aim in mind, the different molecules presented in Section II.…”

Aqueous tape casting and crystallization behavior of gadolinium-doped ceria

“…Although, aqueous tape casting presented above-mentioned advantages, there are still several problems to overcome such as higher crack sensitivity, slow drying of the tape, flocculation and poor wetting of the slips [12,13] rheological properties of ceramic suspension are influenced by many factors, such as pH, type and amount of dispersant and, the number of active groups on the powder surface. The stability and rheological properties of nanosized ceramics powders are more complex due to the particle interactions [14,15]. In this study, the rheological behavior of the slurries with addition of dispersant, binder, and plasticizer is investigated.…”