Measurements and model application on the viscosities of liquid phase in clay based ceramics

Abstract

The model used to predict the liquid viscosity value of clay based ceramics was determined in this study. The viscosity values of liquid phases in clay based ceramic were measured precisely in a closed tube furnace by rotating the spindle in the melts at high temperature. The chemical compositions of the glassy phases in the ceramics were analyzed. The glassy phases were prepared by the pure chemicals after the analysis. The viscosity values of the melts followed Arrhenius assumption. Four different models were applied to calculate the viscosity values of melts in the present study. The predicted results of Urbain model and Riboud model were far away from the experimental results. However, the calculated results of Shaw model (SW model), used to predict the viscosity value of lava), and Modification of Shaw model (M-SW model) were found to be much closer to the experimental results but were still with some deviations. The calculated viscosity values of M-SW model were smaller than the experimental results. On the other hand, M-SW was a reliable predictor of viscosity values of liquid phases in clay based ceramics after modification. The modification of M-SW considered “FeO” as network-modifier and got rid of a part of excess Al₂O₃. The assumptions of SW model and M-SW model limited the accuracy of the prediction results of liquid viscosity values in the clay based ceramics. More experiments were needed to revise the slope intercept data of K₂O and “FeO”.