Solute Segregation at Grain Boundaries and its Effect on Grain Boundary Diffusion Rates

9725047 Yund由饱和了Rb、Sr和Ba等杂质的橄榄长石和斜长石组成的细粒样品将被热压。这些多晶样品将在T和P下退火（和淬火），以建立晶界区域和体晶之间的平衡。利用扫描电镜可以确定晶界区域和相邻区域之间的成分差异。在晶界上，相当于十分之一单层的溶质浓度的差异是可以测定的。将对上述团聚体进行晶界扩散实验。稳定同位素痕量将用于各种T和P，浓度分布将通过离子探针确定。

9725047 Yund Fine-grained samples consisting of forsterite and plagioclase saturated with impurities such as Rb, Sr and Ba will be hot-pressed. These polycrystalline samples will be annealed at T and P (and quenched) in order to establish equilibrium between grain boundary region and the bulk crystal. Compositional differences between the grain boundary region and adjacent regions of the bulk crystal will be determined using SEM. Differences in concentrations of solutes equivalent to a tenth of a monolayer on a grain boundary can be determined. Grain boundary diffusion experiments will be made on the above aggregates. Stable isotope traces will be used at a variety of T and P and concentration profiles will be determined via ion probe.