Dealloying Kinetics of Cu1 − x Ti x on SiO2 Using In Situ X‐Ray Diffraction
| Autor: | T. L Alford, S. W. Russell, James W. Mayer |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Auger electron spectroscopy
Materials science Renewable Energy Sustainability and the Environment Diffusion Analytical chemistry Activation energy Atmospheric temperature range Condensed Matter Physics Rutherford backscattering spectrometry Surfaces Coatings and Films Electronic Optical and Magnetic Materials Chemical kinetics Reaction rate Crystallography Lattice constant Materials Chemistry Electrochemistry |
| Zdroj: | Journal of The Electrochemical Society. 142:1308-1317 |
| ISSN: | 1945-7111 0013-4651 |
| DOI: | 10.1149/1.2044169 |
| Popis: | We study the dealloying of Ti from Cu 1-x Ti x (x∼10 atom percent) alloy films on oxidized Si substrates in the temperature range of 375 to 490 o C and an estimated O 2 partial pressure of ∼10 -6 to 10 -5 Torr. Reaction products were determined to be TiO and Ti 2 O 3 and possibly TiO 2 at the free surface, and TiO at the SiO 2 interface, according to Rutherford backscattering spectrometry and Auger electron spectroscopy. We found that the Cu lattice parameter varies linearly with Ti concentration, and this variation is independent of temperature in this composition range. As a consequence, we were able to study the dealloying kinetics using in situ x-ray diffraction by monitoring the time dependence of the Cu lattice parameter. We observe that the reaction kinetics obey a parabolic rate law, i.e., X 2 Ti,reacted =kt, with a single activation energy of 1.6±0.1 eV, suggesting that one process governs dealloying kinetics over this temperature range. In addition, we note a pronounced composition dependence, in that the reaction rate increases sharply with increasing Ti concentration. These observations suggest that Ti diffusion in Cu is the rate-limiting kinetic process for the dealloying reactions in this temperature regime. We model the dealloying reaction and in so doing estimate the diffusion coefficient for Ti in these alloy films |
| Databáze: | OpenAIRE |
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