THERMODYNAMICS AND MECHANISMS OF SINTERING

A phenomenological overview and exploration of the thermodynamic and geometric factors play a role in the process of densification of model compact systems consisting of crystalline spheres of uniform size in regular and irregular packing that form grain boundaries at every contact point. A further assumption is the presence of isotropic surface and grain boundary energies. Although such systems are unrealistic in comparison with normal powder compacts, their potential sintering behavior can be analyzed and provided with a limiting set of behavior conditions which can be looked upon as one boundary condition. This approach is logically realistic since it is easier to understand and provide a basis for understanding the more complex real powder systems

REACTION OF FUSED SILICA WITH HYDROGEN GAS

Photograph of crown of empress, Ding Ling Tomb, Ming Dynasty Tombs near Beijing, ChinaCrown of empress, 13th Ming Emperor (Zhu Yijun), gold dragons, phoenix, flowers of precious stones, and Kingfisher feathers, Ding Ling Tomb, Underground Palace, Ming Tombs, China