Multicomponent Interstitial Diffusion in and Thermodynamic Characteristics of the Interstitial Solid Solution epsilon-Fe-3(N,C)(1+x) : Nitriding and Nitrocarburizing of Pure alpha-Iron

作者：Woehrle T^*; Leineweber A; Mittemeijer E J

来源：Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science, 2013, 44A(6): 2548-2562.

DOI：10.1007/s11661-013-1640-z

A series of gas nitriding and gas nitrocarburizing experiments was performed at 823 K (550 A degrees C) to investigate the growth kinetics of epsilon-Fe-3(N,C)(1+x) /gamma%26apos;-Fe4N1-z -double layers on pure alpha-iron substrates. The growth rate and composition of the (sub)layers were determined by (sub)layer-thickness measurements using light optical microscopy and electron-probe microanalyses (EPMA), respectively. Models for the growth of bilayers into a substrate, controlled by the interstitial diffusion of two elements (N and C), were applied to the experimental data to determine the intrinsic diffusion coefficients of N and C in epsilon-Fe-3(N,C)(1+x) as well as the self-diffusion coefficient of N in gamma%26apos;-Fe4N1-z . For epsilon-Fe-3(N,C)(1+x) , it was found that the four components of the diffusion matrix, and , are all positive. The significant values of the off-diagonal diffusivities and indicate profound interaction of both interstitial species. Thereby, additional information is obtained about the thermodynamic properties of the epsilon phase in the ternary Fe-N-C system. DOI: 10.

• 出版日期2013-6