Study of the Limiting Shear Stress of Pyrophyllite – Clay Component – Water Composition at Elevated Temperature

Resumo

A sharp reduction in the ultimate shear stress in the range of 20 – 80°C is observed during preparation of specimens of a clay component without thinners that facilitates development of cracks and defects. Use of pyrophyllite in ceramic mixes during specimen preparation provides a gradual reduction in the ultimate shear stress P_m in the range of 20 – 80°C. It is shown that in order to improve specimen drying properties a pyrophyllite – clay – water composition is more homogeneous than a clay – water composition Analysis of specimen P_m under hot forming conditions shows that the relationship Pm = f(t) is not as important as the relationship P_m = f(W,t), where t is temperature, and W is humidity.