Surface segregation measurements of In and S impurities from a dilute Cu(In,S) ternary alloy |
| |
Authors: | M J Madito H C Swart J J Terblans |
| |
Institution: | Department of Physics, University of the Free State, , Bloemfontein, ZA‐9300 South Africa |
| |
Abstract: | The surface segregation of In and S from a dilute Cu(In,S) ternary alloy were measured using Auger electron spectroscopy coupled with a linear programmed heater. The alloy was linearly heated and cooled at constant rates. Segregation data of a linear heat run showed surface segregation of In that reached a maximum surface coverage of 25% followed by S, which reached a coverage of 30%. It was found that after In had reached a maximum surface coverage, it started to desegregate as soon as the S enriched the surface until In was completely replaced by S. The segregation parameters, namely, the pre‐exponential factor (D0), activation energy (Q), segregation energy (ΔG?) and interaction energy (Ω) were extracted from the measured segregation data for both In and S segregation in Cu by simulating the measured segregation data with a theoretical segregation model (modified Darken model). The segregation parameters obtained for In segregation in Cu are D0 = 1.8 ± 0.5 × 10?5 m2 s?1, Q = 184.3 ± 1.0 kJ.mol?1, ΔG? = ?61.4 ± 1.4 kJ.mol‐1, ΩCu?In = 3.0 ± 0.4 kJ.mol?1; for S segregation in Cu the parameters are D0 = 8.9 ± 0.5 × 10?3 m2 s?1, Q = 212.8 ± 3.0 kJ.mol?1, ΔG? = ?120.0 ± 3.5 kJ.mol?1, ΩCu?S = 23.0 ± 2.0 kJ mol?1 and the In and S interaction parameter is ΩIn?S = ?4.0 ± 0.5 kJ.mol?1. The initial parameters used for the Darken calculations were extracted from fits performed with the Fick's and Guttmann model. Copyright © 2013 John Wiley & Sons, Ltd. |
| |
Keywords: | Cu In S In segregation In impurity diffusion S segregation interaction energy |
|
|