Evaluation of diffusion parameters and phase formation between tungsten films and glassy carbon
| Autor: | Johan B. Malherbe, Mbuso Mlambo, M. Madhuku, E.O. Ejeh, Thulani Thokozani Hlatshwayo, M.Y.A. Ismail, T.P. Ntsoane, C.C. Theron, Audu Joseph Innocent, E.G. Njoroge |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Annealing (metallurgy) Analytical chemistry chemistry.chemical_element 02 engineering and technology Sputter deposition Tungsten Glassy carbon 021001 nanoscience & nanotechnology Condensed Matter Physics Rutherford backscattering spectrometry 01 natural sciences Surfaces Coatings and Films Carbide chemistry 0103 physical sciences Crystallite Thin film 0210 nano-technology Instrumentation |
| Zdroj: | Vacuum. 175:109245 |
| ISSN: | 0042-207X |
| DOI: | 10.1016/j.vacuum.2020.109245 |
| Popis: | Thin films of tungsten (W) were deposited on glassy carbon (C) substrates using a magnetron sputtering system. The as-deposited samples were annealed isothermally under vacuum at temperatures ranging from 673 to 1273 K. The structural changes due to thermal annealing were monitored by Rutherford backscattering spectrometry (RBS) and grazing incidence X-ray diffraction (GIXRD). RUMP software was used to simulate the RBS spectra. The thickness of W thin films deposited, atomic composition of deposited layer and the intermixed layer growth were deduced from the RUMP simulation results. The GIXRD analysis showed that carbide formation was first observed at annealing temperature of 1173 K. The kinetics of the solid-state interaction was found to be diffusion controlled at the interface between W and C. The activation energy for the diffusion of C in W was estimated as 2.23 eV. The XRD results showed that the average crystallite size of the as-deposited W film was 9.77 nm. It increased with annealing temperature up to 18.05 nm at 1173 K. The first carbide phase observed was W2C in the sample annealed at 1173 K, while WC was the dominant carbide phase at 1273 K. The stability of W/C system under heat treatments below 1073 K suggests that this system has a promising application for long-term structural integrity of dry cask storage devices. |
| Databáze: | OpenAIRE |
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