Deuterium diffusion and retention in a tungsten–carbon multilayer system

Abstract

Abstract:A tungsten-carbon multilayer system deposited by magnetron sputtering was used as a model system to study deuterium diffusion in tungsten, carbon and related carbides. After deposition the as-deposited multilayer films were annealed at different temperatures to achieve different structures. The structural changes due to annealing were investigated by Rutherford backscattering spectrometry and X-ray diffraction. The results show that diffusion and interaction between tungsten and carbon sets in at 1150 K. Different types of tungsten carbides including WC and W 2 C were formed during different heat treatments. Deuterium implantation experiments proved that deuterium diffusion in this multilayer system can be reduced substantially by formation of the tungsten carbide WC and can be almost completely suppressed by formation of the tungsten subcarbide W 2 C.

Investigation on the influence of tungsten particulate in mechanical and thermal properties of HD50MA180 high density polyethylene composites

“…The presence of planes (110), (200), (211) and (220) confirms the presence of tungsten. The obtained diffraction patterns are in line with the patterns reported for tungsten particles coated with HDPE [8] and tungsten with carbon [22].…”

“…In figure 1, XRD for pure tungsten powder shows strong diffraction peak at 40.3°corresponding to the reflection plane (110) and tiny peaks at 58.7°, 73.6°and 87.1°corresponding to the planes (200), (211) and (220) for pure tungsten [22]. The presence of planes (110), (200), (211) and (220) confirms the presence of tungsten.…”

Interfacial Thermal Conductance between Cu and Diamond with Interconnected W−W2C Interlayer

“…For this reason, only a small amount of W carbides is detected at the W/diamond interface at the temperature of 1073 K, 24 but the Cr, 28 Ti, 25 and Mo 27 films are found to completely transform to carbides at 773, 1073, and 1173 K, respectively. Because the Gibbs free energy for the formation of W 2 C is more negative than WC, W 2 C is more easily formed than WC at 1273 K. However, some studies show that the WC phase is detected in the W−C system at an annealing temperature of 1273 K. 57,58 The diamond substrate in this study is dominated by sp 3 -hybridized bonds, whereas the carbon substrates in the literature 57,58 are dominated by sp 2 -hybridized bonds. The strong binding limits the diffusion of C atoms, and only the W-rich W 2 C phase is formed in this study.…”

Evaluation of diffusion parameters and phase formation between tungsten films and glassy carbon

“…The phases were identified by comparing the peak position in the X-ray diffractograms with the peak position of the tungsten carbide standard tabulated in the ICDD-PDF-2 [40]. The comparison was supported by other papers [18,25,41]. The diffractogram of the as-deposited sample showed the presence of a strong diffraction peak at 2θ position of 39.73° and low intensity peaks at 74.86° and 87.23°, these peaks correspond to the (110), ( 211) and (220) orientation of W, respectively [40].…”

“…This fitting problem at the low energy tail of the RBS is typical of this analytical method. Wang and Jacob [25], attributed this problem to the increasing background as a result of multiple scattering [26] from the overlaying W films, which is not quantitatively reproduced in the RUMP simulation program. Multiple scattering caused the traversing ions to possess reduced energy.…”