Based on the assumption of repulsive forces between the clay particles a formula was developed governing the relationship between shearing stress and impulsive forces. According to Forton the plasticity of a clay body is controlled by two forces;
1. The mutual repulsion of clay particles.
2. The surface tension of water which forces them together through the capillary action of the water films.
The highest possible plasticity is desirable in ceramic bodies for any shaping process and also to facilitate addition of non-plastic material into the body formation without any difficulties. And hence a ceramist always strives to improve the plasticity of the body.
To be contd…….
