Grain-boundary structure

It would appear that the effects of impurities at the grain boundary must be either (a) to increase the diffusion rates or (b) to influence the microstructure and increase the number of short-circuit paths. However, theoretical modelling of the grain boundary structure by Duffy and Tasker and... 

Fig. 8 reveals that under the assumption of reasonable values for the adjustable parameters in Eq. (7) the theoretical predictions compare well to the experimental data. The very different behaviour of special and non-special boundaries reflects an influence of grain boundary structure on grain boundary migration mechanism. In particular, impurities not only may have an effect on migration by impurity drag, but also by changing grain boundary structure itself. This was shown recently by Udler and Seidman in a Monte Carlo... 

Browning, N. D., Moltaji, H. O., and Buban, J. P. (1998 ). Investigation of three-dimensional grain-boundary structure in oxides through multiplescattering analysis of spatially resolved electron-energy-loss spectra. Phys. Rev. B 58, 8289-300. 

Y. Ishida,ed., Grain Boundary Structures and Related Phenomena, Jpn Inst. 

G. A. Chadwick D. A. Smith, Grain Boundary Structures and Properties,... 

D.A. Smith, C.M.F. Rae, and C.R.M. Grovenor. Grain boundary migration. In R.W. Balluffi, editor, Grain Boundary Structure and Kinetics, pages 337-571, Metals Park, OH, 1980. American Society for Metals. 

However, Plateau s laws are not obeyed by the grain boundary structure in the special polycrystal in Fig. 15.15. To achieve local equilibrium at all grain junctions, so that Plateau s laws are obeyed, the faces of each grain must be curved [31]. A boundary structure in which all junctions obey Plateau s laws is presented in Fig. 15.16, which shows a polycrystal consisting of six grains that meet at four vertices. Each grain fully occupies one face of the polycrystal. As in Fig. 15.15,... 

Carter, C. B., Sass, S. L. (1981). Electron diffraction and microscopy techniques for studying grain-boundary structure. J. Amer. Ceramic Soc., 64, 335-45. 

Loberg, B., Norden, H. (1976). High resolution microscopy of grain boundary structure. In Grain Boundary Structure and Properties, edited by G. A. Chadwick D. A. Smith, pp. 1-43. London Academic Press. 

Wagner compared structural and electrical properties of polycrystalline Si layers grown by CVD or LPE (In melt, 947°C, 0.12 pm min-1) with similar grain boundary structures [20]. The measured minority carrier lifetime was always higher and the recombination strength of the defects was smaller in the LPE layers than in the CVD layers. They attributed this to the higher purity of the LPE layer and its lower density of defects (rod-like defects). 

Hondios, E. D., McLean, D. Grain Boundary Structure and Properties. Chadwick, G. A., Smith, D.A. (eds.), New-York Academic Press 1976... 

Fig. 9.39. Interpenetrating lattices used to consider grain boundary structure (courtesy of D. Pawaskar). Open and filled circles correspond to the two host lattices and filled squares correspond to those atoms that are common to both lattices (i.e. the lattice of coincident sites).

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