Effect of Calcined Colemanite Addition on the Rheological Behaviour of Porcelain Suspension |
| Y. Özdemir, S. Akpınar, S. Abbak and A. Evcin
Afyon Kocatepe University, Material Science and Engineering Department, Afyonkarahisar, Turkey |
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| A standard composition for hard porcelain production was prepared by mixing 50 wt% kaolin, 25 wt% potassium feldspar and 25 wt% quartz. Calcined colemanite powders were added to the porcelain formulation by replacing the potassium feldspar up to 5 wt% to explore its effect on the rheological behaviour of porcelain slip casting. A rheological study has been carried out in order to optimize the processing of the slip casting by using a rotational stress-controlled rheometer. The measurements were performed at constant temperature (25°C) using a parallel plate configuration. Sweep measurements were then conducted in the shear rates ranging from about 0.1-1000 s-1. The stability of the suspensions with ammonium polyacrylate (Darvan 821A) was determined in order to select the suitable dispersant amount. In order to achieve casting of acceptable characteristics on a plaster of Paris mould, the slurry should have the appropriate thixotropic or shear-thinning behaviours. Therefore, the same favourable thixotropic behaviour of slurries of different amount of calcined colemanite powders, the solid contents of the slurries have been optimised. |
DOI: 10.12693/APhysPolA.132.825 topics: rheology, colemanite, slip casting |