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

Innocent, A J; Hlatshwayo, Thulani Thokozani; Njoroge, E.G.; Ntsoane, T.P.; Madhuku, M.; Ejeh, E.O.; Mlambo, Mbuso; Ismail, M.Y.A.; Theron, C.C.; Malherbe, J.B.

doi:10.1016/j.vacuum.2020.109245

Cited by 11 publications

(5 citation statements)

References 42 publications

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“…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.…”

Section: Methodsmentioning

confidence: 69%

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

Zhang

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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Manipulating the interfacial structure is vital to enhancing the interfacial thermal conductance (G) in Cu/diamond composites for promising thermal management applications. An interconnected interlayer is frequently observed in Cu/diamond composites; however, the G between Cu and diamond with an interconnected interlayer has not been addressed so far and thus is attracting extensive attention in the field. In this study, we designed three kinds of interlayers between a Cu film and a diamond substrate by magnetron sputtering coupled with heat treatment, including a W interlayer, an interconnected W–W2C interlayer, and a W2C interlayer, to comparatively elucidate the relationship between the interfacial structure and the interfacial thermal conductance. For the first time, we experimentally measured the G between Cu and diamond with an interconnected interlayer by a time-domain thermoreflectance technique. The Cu/W–W2C/diamond structure exhibits an intermediate G value of 25.8 MW/m2 K, higher than the 19.9 MW/m2 K value for the Cu/W2C/diamond structure and lower than the 29.4 MW/m2 K value for the Cu/W/diamond structure. The molecular dynamics simulations show that the G of the individual W2C/diamond interface is much higher than those of the individual Cu/diamond and W/diamond interfaces and W2C could reduce the vibrational mismatch between Cu and diamond; however, the G of the Cu/W2C/diamond structure is reduced by the lower thermal conductivity of W2C. This study provides insights into the relationship between the interconnected interfacial structure and the G between Cu and diamond and offers guidance for interface design to improve the thermal conductivity in Cu/diamond composites.

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Section: Methodsmentioning

confidence: 69%

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

Zhang

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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“…Therefore, the improvement and performance of the materials used to manufacture dry storage devices are vital. Previous studies on the migration behaviour of fission products in glassy carbon have shown that glassy carbon can serve as an alternative material to be considered for the dry cask needed for nuclear waste management [2][3][4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Effects of implantation temperature and annealing on structural evolution and migration of Se into glassy carbon

Adeojo

Malherbe

Azarov

et al. 2022

Solid State Sciences

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“…A key property for a nuclear waste storage material is low diffusivity for the radioactive materials. Although there had been a few reports of diffusion of fission product elements in glassy carbon [17][18][19][21][22][23][24][25][26], this is the prime reason for this study, i.e. to determine the diffusivity of the radiological important fission product, strontium, in glassy carbon.…”

Section: Introductionmentioning

confidence: 99%

Diffusion of strontium implanted in glassy carbon

et al. 2021

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Glassy carbon has properties making it attractive as a containment material for radioactive waste. In this study, the diffusivity of the radiological important fission product, strontium, is measured. Two hundred kiloelectronvolt strontium ions were implanted at room temperature. The implanted samples were either annealed isochronally for 1 h up to 900°C or by increasing the temperature linearly up to 648°C. The Sr profiles were determined by Rutherford backscattering spectrometry (RBS). The isochronally annealed samples showed Fickian diffusion at 300°C ( D = 6.7 × 10 −19 m 2 s −1 ) with segregation occurring at the higher temperatures. Raman spectroscopy indicated a link between damage annealing and the onset of segregation. During increasing temperature, the system is dynamic with diffusion taking place. An equation to determine diffusion coefficients for ramped heating was derived. Fickian diffusion occurred with an activation energy of 1.97 eV for 414–454°C, and from 458 to 558°C, it was 0.184 eV. At higher temperatures, a segregation of the strontium towards the surface was observed. A calculation of the heat of segregation of Sr in carbon supports this segregation. The results show that the in situ RBS measurements with a linear increase in temperature give additional information compared with the conventional isochronal annealing.

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

Cited by 11 publications

References 42 publications

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

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

Effects of implantation temperature and annealing on structural evolution and migration of Se into glassy carbon

Diffusion of strontium implanted in glassy carbon

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

Cited by 11 publications

References 42 publications

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

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

Effects of implantation temperature and annealing on structural evolution and migration of Se into glassy carbon

Diffusion of strontium implanted in glassy carbon

Contact Info

Product

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

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