A COMBINATION OF SFM AND TOF-SIMS IMAGING FOR OBSERVING LOCAL INHOMOGENEITIES IN MORPHOLOGY AND COMPOSITION - AGED CALCITE SURFACES

Because of their extremely high surface sensitivity, time-of-flight se condary ion mass spectrometry (TOF-SIMS) and scanning force microscopy (SFM) have been used in combination to provide complementary informat ion about the chemical and morphological behaviour of calcite (CaCO3) surfaces during exposure to air, To allow time-resolved analysis of id entical features with both techniques in turn, two types of orientatio n markers were used: pits etched with the Ga+ beam and naturally disti nctive features of the surface, Freshly cleaved calcite surfaces had a tomically hat cleavage terraces that were chemically homogeneous, wher eas during aging for several months in air, monovalent salt crystallit es (Na, ii, 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 observe d in any of the single crystal samples examined, so the material has b een interpreted to have diffused from the bulk, probably along crystal lattice defects, (C) 1997 John Wiley & Sons, Ltd.