Abstract
The chemical and phase composition, and cleavage surface morphology and the vapor composition of potassium chloride (KCl) crystals formed as a result of the thermostimulated surface autosegregation (TSAS) are studied by methods of microprobe analysis, high-resolution scanning electron microscopy, optical digital microscopy, and quadrupole mass spectrometry. It is experimentally found that the stoichiometry (K/Cl <1) in the surface layers changes due to a decrease in the potassium surface concentration from 5% in the initial samples to 12% after annealing at a temperature of 1023 K. After annealing at a temperature of 573 K for 5 h at P = 10−3 Pa, the potassium deficiency increases to 17%. The competing processes resulting in TSAS in potassium chloride are the self-diffusion of potassium to the surface and its subsequent sublimation. During the annealing processes the sublimation of potassium dominates, but at a temperature near fusion, the self-diffusion of potassium to the surface increases. It is concluded that potassium chloride analogous to sodium chloride is a rather stable compound to TSAS. This is an additional argument of the important role of ionic bonds in a decrease in the tendency of chemical compounds to surface autosegregation.
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Yu. Ya. Tomashpolsky, Russ. J. Gen. Chem. 72, 632 (2002).
Yu. Ya. Tomashpolsky, N. V. Sadovskaya, N. V. Kozlova, et al., J. Surf. Invest.: X-Ray, Synchrotron Neutron Tech. 6, 930 (2012).
Yu. Ya. Tomashpolsky, N. V. Sadovskaya, and G. A. Grigor’eva, J. Surf. Invest.: X-Ray, Synchrotron Neutron Tech. 7, 900 (2013).
J. Goldstein, D. Newbury, and P. Echlin, et al., Scanning Electron Microscopy and X-Ray Microanalysis (Plenum, New York, 1981).
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Original Russian Text © Yu.Ya. Tomashpolsky, V.M. Matyuk, N.V. Sadovskaya, P.S. Vorontsov, 2014, published in Poverkhnost’. Rentgenovskie, Sinkhrotronnye i Neitronnye Issledovaniya, 2014, No. 8, pp. 73–76.
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Tomashpolsky, Y.Y., Matyuk, V.M., Sadovskaya, N.V. et al. Thermostimulated surface segregation processes in ionic crystals: Potassium chloride. J. Surf. Investig. 8, 801–804 (2014). https://doi.org/10.1134/S1027451014040314
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DOI: https://doi.org/10.1134/S1027451014040314