Abstract
The relation between the nature of surfaces and interfaces, and the ceramics fabrication process, is discussed; and a concept, “free energy theory of material transport” is proposed to explain the diffusion process observed during sintering. In the theory, the excess energy stored at the surface and/or interface in the system is considered to stimulate the material transport directly. This contrasts with the traditional “vacancy theory” in which diffusion during sintering is considered to be promoted by the surface and/or interface tension.
The background of the free energy theory is explained based on the difference of the nature between the energy and tension. The densification, grain growth, and the diffusional creep of elastic solids are treated to illustrate the theory.
