Dispersant-ethyl cellulose binder interactions at the Ni particle-dihydroterpineol interface

The interaction of a dispersant and a binder at the Ni particle surface is investigated to identify their influence on the dispersion stability of Ni particles in dihydroterpineol (DHT). Six different commercial dispersants are used to obtain a highly dispersed Ni suspension, and ethyl cellulose (EC) is used as a binder for the preparation of a Ni paste. The effectiveness of the dispersants on the dispersion stability of the Ni particles in DHT is evaluated by measuring the rheological behavior of the Ni suspension. Hypermer KD3 and RE610, among six different commercial dispersants, are found to be an effective dispersant for the Ni particles in DHT without EC. However, upon the addition of EC, different rheological behaviors of the Ni suspensions are shown according to the added dispersants. EC does not affect the rheological behavior of the RE610-stabilized Ni suspension. On the other hand, the addition of EC increases the apparent and relative viscosities of the Hypermer KD3-stabilized Ni suspension and causes a transition in rheological behavior from shear thinning behavior to shear thickening behavior. The adsorption results reveal that the deterioration in the stability of the Hypermer KD3-stabilized Ni suspension with the addition of EC is due to the partial displacement of the preadsorbed Hypermer KD3 by the EC. The influence of the interactions between the dispersant and binder on the dispersion stability of the Ni pastes is also confirmed via observations of the variations in the agglomerated particle size with the addition of EC.