Carbon diffusion paths in Ni-Ta-C system

Abstract

Electron probe microanalysis and SEM were employed to study the phase equilibria and diffusion paths in C-Ni₈Ta, C-Ni₃Ta, C-Ni₂Ta diffusion couples after annealed at 1100 °C for 120 h or at 1200 °C for 120 h and then at 1100 °C for 24 h. Attempt was made to use the calculated stability diagram of carbon activity to explain the experimental observations. The phases formed in the diffusion layers were all in the prediced ranges.

Keywords

diffusion path / diffusion couple / Ni-Ta-C / phase diagram / stability diagram

References

[1] JacksonM R. Composites of γ+TaC in Ni-Ta-C ternary system. Metall Trans, 1977, 8A: 905-913

[2] Holleck H. Binary und ternary carbide und nitride der ubergangsmetalle und ihre phasenbeziehungen, 1981. 170–196

[3] Fernandez GuillermentA. Thermodynamic properties of the Fe-Co-Ni-C system. Z Metallkde, 1988, 79: 524-536

[4] AnsaraI, SellebyM. Thermodynamic analysis of the Ni-Ta system. CALPHAD, 1994, 18: 99-107

[5] FriskK, Fernandez GuillermentA. Gibbs energy coupling of phase diagram and thermochemistry in the tantanum-carbon system. J Alloys Compounds, 1996, 238: 167-179