Wagner interaction coefficient between nitrogen and cobalt in liquid nickel-based alloy

The report describes a simple theory of thermodynamic properties of nitrogen solutions in liquid Ni– Co alloys. This theory is completely analogous to the theory for liquid nitrogen solutions in alloys of the Fe– Cr system proposed previously by the authors in 2019. The theory is based on lattice model of the Ni– Co solutions. The model assumes FCC lattice. In the sites of this lattice are the atoms of Ni and Co. Nitrogen atoms are located in octahedral interstices. The nitrogen atom interacts only with the metal atoms located in the lattice sites neighbouring to it. This interaction is pairwise. The initial values for the calculation are the Sieverts law constants for nitrogen solubility of in liquid nickel and in liquid cobalt. The result of the calculation is the value of the Wagner interaction coefficient in liquid nickel-based alloys at 1873 K = –1,35. This value is in good agreement with the experimental data (Kowanda and Speidel, 2003).

1. Wagner Carl. Thermodynamics of Alloys. Cambridge, AddisonWesley Press, 1952, 162 p. (Russ. ed.: Wagner C. Termodinamika splavov. Moscow: Metallurgizdat, 1957, 179 p.).

2. Lupis C.H.P., Elliott J.F. The relation between interaction coefficients ε and e. Transactions of the Metallurgical Society of AIME. 1965, vol. 233, no. 1, pp. 257–258.

3. Sieverts A. Zur Kenntnis der Okklusion und Diffusion von Gasen in Metalle. Zeitschrift für physikalische Chemie. 1907, vol. 60, no. 2, pp. 129–201. (In Germ.). https://doi.org/10.1515/zpch-1907-6009

4. Bolʼshov L.A., Korneichuk S.K. Thermodynamics of liquid nitrogen solutions in chromium. Izvestiya. Ferrous Metallurgy. 2019, vol. 62, no. 5, pp. 387–393. (In Russ.). https://doi.org/10.17073/0368-0797-2019-5-387-393

5. Abdulrahman R.F., Hendry A. The solubility of nitrogen in liquid pure nickel. Metallurgical and Materials Transactions B. 2001, vol. 32, no. 6, pp. 1095–1101. http://doi.org/10.1007/s11663-001-0097-4

6. Blossey K.G., Pehlke R.D. Solubility of nitrogen in liquid cobalt alloys. Transactions of the Metallurgical Society of AIME. 1966, vol. 236, no. 1, pp. 28–32.

7. Kowanda C., Speidel M.O. Solubility of nitrogen in liquid nickel and binary Ni–Xi alloys (Xi = Cr, Mo, W, Mn, Fe, Co) under elevated pressure. Scripta Materialia. 2003, vol. 48, no. 8, pp. 1073–1078. https://doi.org/10.1016/S1359-6462(02)00628-0