Characterization of iron nitrides prepared by spark erosion, plasma nitriding, and plasma immersion ion implantation

Jirásková, Y.; Havlíček, S.; Schneeweiss, O.; Peřina, Vratislav; Blawert, Carsten

doi:10.1016/s0304-8853(01)00426-7

Cited by 33 publications

(17 citation statements)

References 46 publications

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“…The spectra were fitted as a superposition of the sub-spectra of different phases: a nitrogen supersatured solid phase γ N , a hexagonal ε phase and the γ phase. Table 1 presents the Mössbauer parameters used for these different phases, which are in agreement with previous results [4][5][6][7][8][9][10][11]. Figure 3 shows the phase fractions obtained from the Mössbauer fittings as a function of t N , where γ N = γ N (p) + γ N (m).…”

Section: Resultssupporting

confidence: 86%

Improving the empirical model for plasma nitrided AISI 316L corrosion resistance based on Mössbauer spectroscopy

2011

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Traditional plasma nitriding treatments using temperatures ranging from approximately 650 to 730 K can improve wear, corrosion resistance and surface hardness on stainless steels. The nitrided layer consists of some iron nitrides: the cubic γ phase (Fe 4 N), the hexagonal phase ε (Fe 2−3 N) and a nitrogen supersatured solid phase γ N . An empirical model is proposed to explain the corrosion resistance of AISI 316L and ASTM F138 nitrided samples based on Mössbauer Spectroscopy results: the larger the ratio between ε and γ phase fractions of the sample, the better its resistance corrosion is. In this work, this model is examined using some new results of AISI 316L samples, nitrided under the same previous conditions of gas composition and temperature, but at different pressure, for 3, 4 and 5 h. The sample nitrided for 4 h, whose value for ε/γ is maximum (= 0.73), shows a slightly better response than the other two samples, nitrided for 5 and 3 h (ε/γ = 0.72 and 0.59, respectively). Moreover, these samples show very similar behavior. Therefore, this set of samples was not suitable to test the empirical model. However, the comparison between the present results of potentiodynamic polarization curves and those obtained previously at 4 and 4.5 torr, could indicated that the corrosion resistance of the sample which only presents the γ N phase was the worst of them. Moreover, the empirical model seems not to be ready to explain the response to corrosion and it should be improved including the γ N phase.

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Section: Resultssupporting

confidence: 86%

Improving the empirical model for plasma nitrided AISI 316L corrosion resistance based on Mössbauer spectroscopy

2011

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“…This table extends previous tabulations in Refs. [14,51,99], of whom we have not included a few Mössbauer studies that gave only incomplete information. Data that we consider to be unreliable, are put in italics.…”

Section: Mössbauer and Nmr Experimentsmentioning

confidence: 99%

“…The only two samples that show drastically deviating results are those from Ref. [99], produced by spark erosion and by plasma nitriding -these samples contained several phases, which made it hard to extract reliable parameters for γ′-Fe 4 N. The low-temperature hyperfine field for Fe-I (-36.9 T near 0 K, average over the reliable lowtemperature values from Table 5 This decreasing trend is continued at the highest measured temperature [14] of 823 K (Fe-I: -0.17 mm/s, Fe-II: -0.08 mm/s). If the measured ε -values are converted to V zz (which does not depend on the angle θ with the hyperfine field, and which is the quantity that can be determined by ab initio calculations), then nearly identical V zz values are found for Fe-IIa and Fe-IIb.…”

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confidence: 98%

The magnetization of γ′‐Fe₄N: theory vs. experiment

Blancá

Desimoni

Christensen

et al. 2009

Physica Status Solidi (b)

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By reviewing the experimental and theoretical literature on γ′‐Fe4N, and by a systematic survey of predictions by the LDA, PBE, WC, LDA + U (2×), PBE + U (2×) and B3PW91 exchange‐correlation functionals, the structural, magnetic and hyperfine properties of this material as well as their pressure dependencies are interpreted. The hypothesis is put forward that γ′‐Fe4N as found in Nature is exactly at a steep transition between low‐spin and high‐spin behaviour. PBE + U (U = 0.4 eV) is identified as the most accurate exchange‐correlation functional for this material, although it is needed to fix the magnetization at the experimental value to obtain a satisfying description. Remaining disagreement between theory and experiment is pointed out. A recent experimental claim for a giant magnetic moment in γ′‐Fe4N is discussed, and is not reproduced by our calculations. We expect that the new insight obtained in the present work can lead to a consistent ab initio modeling of other materials in the iron‐nitrogen binary system. In an accompanying didactic section, the physics behind some common exchange‐correlation functionals is outlined. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…Iron nitride films or particles have been prepared by various methods [4][5][6][7][8][9]. Iron nitrides with low nitrogen contents have been extensively studied, whereas iron nitrides with high nitrogen contents have not been well investigated.…”

Section: Introductionmentioning

confidence: 99%

Mössbauer study of iron nitride films produced by pulsed laser deposition

2011

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Iron nitride films were produced by pulsed laser deposition of Fe onto an Al substrate in an N 2 atmosphere and their Mössbauer spectra and powder X-ray diffraction patterns were measured. The nitrogen content of the iron nitride films varied depending on the N 2 pressure. Under high N 2 pressures, γ "-FeN (ZnS structure) and γ "'-FeN (NaCl structure) were obtained. The yields of these two phases could be controlled by varying the Al substrate temperature. γ "-FeN and γ "'-FeN were found to be paramagnetic and antiferromagnetic, respectively, at 5 K.

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Characterization of iron nitrides prepared by spark erosion, plasma nitriding, and plasma immersion ion implantation

Cited by 33 publications

References 46 publications

Improving the empirical model for plasma nitrided AISI 316L corrosion resistance based on Mössbauer spectroscopy

Improving the empirical model for plasma nitrided AISI 316L corrosion resistance based on Mössbauer spectroscopy

The magnetization of γ′‐Fe₄N: theory vs. experiment

Mössbauer study of iron nitride films produced by pulsed laser deposition

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Characterization of iron nitrides prepared by spark erosion, plasma nitriding, and plasma immersion ion implantation

Cited by 33 publications

References 46 publications

Improving the empirical model for plasma nitrided AISI 316L corrosion resistance based on Mössbauer spectroscopy

Improving the empirical model for plasma nitrided AISI 316L corrosion resistance based on Mössbauer spectroscopy

The magnetization of γ′‐Fe4N: theory vs. experiment

Mössbauer study of iron nitride films produced by pulsed laser deposition

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The magnetization of γ′‐Fe₄N: theory vs. experiment