Surface energy and strain effects on calcite dissolution

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The objective is to determine experimentally the effect of surface reactivity (in terms of the orientation of the surface relative to a cleavage plane) as well as stress (elastic strain and plastic deformation) on the mechanisms and rates of calcite dissolution. The techniques used will be: in-situ fluid-cell Atomic Force Microscopy (AFM) .Vertical Scanning Interferometry (VSI) and Transmission Electron Microscopy (TEM). We will study the dissolution and surface reorganisation of calcite single-crystal surfaces polished with varying miscut angles (e.g., 5°, 10°, 20°) to the cleavage planes. The effect of the saturation state of the fluid will be determined. The role of elastic strain will be determined using a newly developed microbending method to stress single-crystals of calcite and gypsum up to the elastic limit, without brittle failure, within the fluid cell of an AFM. The effect of plastic deformation on the dissolution mechanism will be studied as a function of fluid saturation. TEM will be used to characterise surface reconstruction, dislocation structure of the samples, and defects caused by sample preparation or by the applied stress.