A combination of SFM and TOF‐SIMS imaging for observing local inhomogenieties in morphology and composition: aged calcite surfaces

Because of their extremely high surface sensitivity, time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) and scanning force microscopy (SFM) have been used in combination to provide complementary information about the chemical and morphological behaviour of calcite (CaCO 3 ) surfaces during exposure to air. To allow time‐resolved analysis of identical features with both techniques in turn, two types of orientation markers were used: pits etched with the Ga + beam and naturally distinctive features of the surface. Freshly cleaved calcite surfaces had atomically flat cleavage terraces that were chemically homogeneous, whereas during aging for several months in air, monovalent salt crystallites (Na, K, Cl, F) developed spontaneously along intersecting cleavage directions. Contamination from external sources has been shown to be unlikely. No micro‐ or nanometre scale fractures have ever been observed in any of the single crystal samples examined, so the material has been interpreted to have diffused from the bulk, probably along crystal lattice defects. © 1997 John Wiley & Sons, Ltd.