Driving Force and Basic Phenomena

The driving force of sintering is the reduction of the total interfacial energy. The total interfacial energy of a powder compact is expressed as yA, where y is the specific surface (interface) energy and A the total surface (interface) area of the compact. The reduction of the total energy can be expressed as 

the change in interfacial energy (Ay) is due to densification and the change in interfacial area is due to grain coarsening. For solid state sintering, Ay is related to the replacement of solid/vapour interfaces (surface) by 

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