Grain boundary interaction with pores

We often start with very porous material so the concentration of pores may be large. We will extend this discussion in Chapter 24 (sintering). We may want a porous material (e.g., MCM-41). Pores interact with grain boundaries, phase boundaries, etc. 

With the definition of the pore mobility, it is possible to analyze the influence of the interactions between the pores and the grain boundaries on the kinetics of grain growth. There are two cases that can be considered (i) the pore becomes separated from the boundary and (ii) the pore remains attached to the boundary. 

Schematic representation of the effects of powder size distribution on the sintered microstructure. For eJtample, in (a-1), a narrow size distribution and ooturol of the grain-boundary pore interaction result in a dense sintered ceramic with a grain size slightly larger than the original particle size. From Barringer el at. [166). A distribution of particle sizes may result in better sintering, however. See Fig, 39 in Chapter II.

The petrophysical origin of the IP effects is connected with electrochemical processes of the electronic-ionic interaction, interface properties at the grain-fluid boundary region, cation exchange phenomenon, pore constrictivity, and other effects controlled by rock components, their distribution, and interaction (Fig. 8.38). 

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