Models grain boundaries

Eiler JM, Baumgartner LP, Valley JW (1992) Intercrystalline stable isotope diffusion a fast grain boundary model. Contrib Mineral Petrol 112 543-557... 

Grain boundary models were developed primarily for metals. We can assume that the above mentioned ideas on the structure and energy of grain boundaries also hold, in essence, for ionic, covalent, and van der Waals crystals as well [M. W. Finnis, M. Riihle (1993)]. 

Fig. 19 Grain boundary model of glassy film in Si N ceramics...

Figure 1. Energy band profile of sintered materials based on heterostmcture grain boundary model.

For the theoretical interpretation of film stresses of crystalline films, interaction across grain boundaries often appears to be the dominating effect. Hoffman et al. [144] tried to explain the tensile stress behaviour of Ni films through a grain boundary model, and Pulker et al. were successful in interpreting the tensile stress behaviour of pure and doped MgF2 films [159 a-c] and of pure Cr films [166] by analogue mathematical treatments. 

Because of its significance, the grain boundary model is explained briefly in the following. 

According to die grain boundary model, a reduction in mechanical stress arises if ... 

Case 2 follows from a purely energetic treatment of the grain boundary model ... 

Porous layer with grain boundary model... 

It is not possible at this point to make a completely definitive statement about the sintering mechanism or mechanisms in alumina. However, most of the kinetic data seem to indicate grain boundary diffusion kinetics. The most completely characterized powder (sized Alcoa A-14) followed the grain boundary model very closely after a small, temperature-independent length correction and a short volume kinetics portion. Clustered powders either... 

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