Ceramics-Silikáty 33, (1) 11 - 16 (1989)

The capillary viscometer method was used to determine the constitutive equation for two α-Al₂O₃ pastes with different submicron particle sizes. Over the shear rate interval measured the two pastes are described by the constitutive equation for the generalized viscoplastic liquid. With increasing shear rate, the paste with the larger particle size shows a change in rheological behaviour and exhibits dilatancy. It was also found that the critical stress corresponding to the rapid increase in the paste viscosity and subsequent forcing the plasticizer out of the paste, increases with decreasing particle size.