Gas-Solid Nitrocarburizing of Steels: Kinetic Modeling and Experimental Validation

The study is devoted to define the optimal conditions
for the nitriding of pure iron at atmospheric pressure by using NH3-
Ar-C3H8 gas mixtures. After studying the mechanisms of phase
formation and mass transfer at the gas-solid interface, a mathematical
model is developed in order to predict the nitrogen transfer rate in the
solid, the ε-carbonitride layer growth rate and the nitrogen and
carbon concentration profiles. In order to validate the model and to
show its possibilities, it is compared with thermogravimetric
experiments, analyses and metallurgical observations (X-ray
diffraction, optical microscopy and electron microprobe analysis).
Results obtained allow us to demonstrate the sound correlation
between the experimental results and the theoretical predictions.

• L. Torchane

• Gaseous Nitrocarburizing
• Kinetic Model
• Diffusion
• Layer Growth Kinetic.

[1] M.A.J. Somers, P.F. Colijn, W.G. Sloof and E.J. Mittemeijer, Z. Metallkd., Vol.81, (1990), p.33-43.
[2] J. Slycke, and L. Sproge, Surface Engineering, Vol.5 (2), (1989), p.125-140.
[3] M.A.J. Somers and E.J. Mittemeijer, Surface Engineering, vol.3 (2), (1987), p.123-137.
[4] M.A.J. Somers, and E.J. Mittemeijer, Metall. Mater. Trans. A, Vol.29A, (1995),p.57-74.
[5] L. Torchane, Ph. Bilger, J. Dulcy and M. Gantois, Metall. Mater. Trans. A, Vol.27A, (1996), p.1823-1835.
[6] H. Du and J. Agren, Trita-Mac 0570 (1994), Roy. Inst. of Tech., Stockholm, Sweeden.
[7] B. Prenosil, Konove Mater., Vol.3, (1965), p.69-87.
[8] Yu.M. Lakhtin and Ya.D. Kogan, Mashinostroenie, Moscow, (1976).
[9] A. Marciniak, Surface Engineering, Vol.1 (4), (1985), p.283-88.
[10] F.K. Naumann, G. Langenscheid, Arch. EisenhŸttenwes, Vol.36 (9), (1965), p. 677-682.
[11] J. Slycke, L. Sproge and J. Agren, Scandinavian Journal of Metallurgy, 17, (1988), p.122-126.
[12] J. Kunze; Thermodynamics, Physical Research, Vol.16, AkademieVerlag, Berlin, (1990).
[13] H. Du, J. Phase equilibria, Vol.14 (6), (1993), p.682-693.
[14] H. Du and J. Agren, Metall. Mater. Trans. A, Vol.27A, (1996), p.1073-1080.
[15] E.J. Mittemeijer and M.A.J. Somers, Surface Engineering, Vol.13, No.6, (1997), p.483-497.
[16] L. Torchane: Ph.D. Thesis, I.N.P.L., Nancy, France, (1994).
[17] L. Torchane, Ph. Bilger, J. Dulcy, and M. Gantois: Mater. Sci. Forum, Vol.163-165, (1994), p.707-712.
[18] L. Torchane, Ph. Bilger, J. Dulcy and M. Gantois, entropie, No.202/203, (1997), p.45-49.
[19] M. Gantois, Mater. Sci. Forum, Vol.163-165, (1994), p.37-48.
[20] Y. Adda, and J. Phillibert, Tome I, Sarclay, France, (1966).
[21] L.S. Darken, Trans. AIME, Vol.175, (1948), p.184-94.
[22] K. Schwerdtfeger, P. Grieveson, and E.T. Turkdogan: Trans. AIME, Vol.245, (1969), p.2461-2466.
[23] H.C.F. Rozendaal, P.F. Colijn and E.J. Mittemeijer, Surface Engineering, Vol.30, No.1, (1985), also published in Heat Treatment '84', The Metal Society, London, (1984), 31.1-31.16.