1. Calculation of the contribution to grain boundary diffusion in ionic systems that arises from enhanced defect concentrations adjacent to the boundary
- Author
-
Chang Kyung Kim, Bernhardt J. Wuensch, and Yong-Chae Chung
- Subjects
Molecular diffusion ,Diffusion equation ,Condensed matter physics ,Chemistry ,Diffusion ,Mason–Weaver equation ,General Physics and Astronomy ,Effective diffusion coefficient ,Boundary (topology) ,Grain boundary diffusion coefficient ,Grain boundary - Abstract
The enhancement of the concentration of a defect in the space-charge region near a grain boundary in an intrinsic ionic system was used to specify the change in the corresponding diffusion coefficient as a function of distance, x, normal to the boundary. This zone of enhanced and continuously varying diffusivity serves as a vehicle for enhanced transport along the boundary in addition to the expected contribution arising from the different structure at the boundary core. A two-dimensional diffusion equation was established for concentration c(x,y,t) in the space-charged region, solved numerically using the Crank–Nicolson finite-difference method, and integrated normal to the boundary to provide the average concentration gradient c(y,t) along the boundary—the solute distribution usually measured by experiment. The present gradients were analyzed in the same fashion as experimental data using a recent solution to the conventional model for the grain–boundary diffusion problem in which the interface is trea...
- Published
- 2000