A study of iron nitrogenation by hot isostatic pressing

• Published in: Journal of alloys and compounds Vol. 270; no. 1; pp. 168 - 174
• Main Authors: Chartier, P, Eymery, J.P, Dedieu, E, Zouggar, M, Beaufort, M.F, Grosbras, M
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 29.05.1998; Elsevier
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; EXAFS; Fe-Mössbauer spectroscopy; Iron nitride; Materials science; Materials synthesis; materials processing; Metals. Metallurgy; Physics; Powder metallurgy. Composite materials; Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation; Prepartion; Production techniques; Technology; X-ray diffraction; X-ray diffraction; Prepartion; Fe-Mössbauer spectroscopy; Iron nitride; EXAFS; Ball mill; Hot isostatic pressing; Nitriding; Transition metal; Iron; Moessbauer spectrometry; Experimental study; Powder metallurgy; Mechanical alloying; X ray diffraction; SEM; Defect structure; Diffusion
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/S0925-8388(98)00460-5

In this study a hot isostatic pressing (HIP) furnace under high temperature and high nitrogen pressure is used to perform nitrogen diffusion in mechanically processed iron powders. After hipping, the γ′-Fe 4N phase is formed while unreacted b.c.c. iron also remains in the powder. The amount of γ′-Fe 4N is estimated by calculating the relative X-ray diffraction peak intensity. The latter amount increases with increasing milling time because of new surface formation and defect creation. The nitrogen diffusion into grains occurs for a minimum value of the HIP pressure, then the alloying of nitrogen with iron appears for a minimum temperature. Mössbauer and EXAFS analyses indicate that the iron nitride is mainly located at the surface of the powder grains.