Relative roles of ion energy, ion flux, and sample temperature in low-energy nitrogen ion implantation of FeCrNi stainless steel

Williamson, D. L.; Davis, J.A.; Wilbur, P. J.; Vajo, John J.; Wei, Ronghua; Matossian, J. N.

doi:10.1016/s0168-583x(97)00033-5

Cited by 97 publications

(38 citation statements)

References 7 publications

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“…[22,[31][32][33][34][35][36][37][38][39] Similar to low-temperature carburization, austenitic stainless steel can be nitrided at low temperature (T / 723 K) to prevent the precipitation of nitrides. In dilute solution, interestingly, carbon [15] diffuses much faster than nitrogen [40] at these temperatures, although the empirical radius of carbon (r C = 70 pm) is somewhat larger than that of nitrogen (r N = 65 pm).…”

Section: Physical Origin Of Enhanced Diffusionmentioning

confidence: 99%

Enhanced Carbon Diffusion in Austenitic Stainless Steel Carburized at Low Temperature

Ernst

Avishai

Kahn

et al. 2009

Metall Mater Trans A

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Austenitic stainless steel AISI 316L was carburized by a novel, low-temperature gas-phase process. Using a calibrated scanning Auger microprobe (SAM) analysis of cross-sectional specimens under dynamic sputtering, we determined the fraction-depth profile of carbon. The profile is concave-very different from the shape expected for concentration-independent diffusion-and indicates a carbide-free solid solution with carbon levels up to 15 at. pct and a case depth of %30 lm. A Boltzmann-Matano analysis with a careful evaluation of the stochastic and potential systematic errors indicates that increasing levels of carbon significantly enhance carbon diffusion. For the highest carbon level observed (15 at. pct), the carbon diffusion coefficient is more than two orders of magnitude larger than in dilute solution. The most likely explanation for this strong increase is that carbon-induced local expansion of metal-metal atom distances, observed as an expansion of the lattice parameter, reduces the activation energy for carbon diffusion.

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Section: Physical Origin Of Enhanced Diffusionmentioning

confidence: 99%

Enhanced Carbon Diffusion in Austenitic Stainless Steel Carburized at Low Temperature

Ernst

Avishai

Kahn

et al. 2009

Metall Mater Trans A

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“…The nitrogen diffusion in nitrogen-expanded austenite ( N ) was found to be significantly faster than in austenite, and similar diffusion coefficients and activation energies between 0.8 and 1.1 eV have been measured 15,16 for some of the abovementioned methods. These activation energies are lower than the values of 1.2-1.7 eV for diffusion of nitrogen in pure -Fe obtained from various literature data.…”

Section: Introductionmentioning

confidence: 85%

Changes in austenitic steel surface induced by thermal and implantation treatments studied by Mössbauer spectroscopy

Jirásková

Schneeweiss

Blawert

2006

Surface & Interface Analysis

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The surface properties of austenitic (fcc) stainless steel samples in the as-prepared and implanted states were studied. The surface modification was done by plasma immersion ion implantation in methane. This process, done at a temperature of 400°C in a short time of 3 h, facilitates the enrichment of the steel surface by a higher carbon content. It reaches about 7 at% C in the top surface layers (∼500 nm) and decreases to the nominal value at approximately 10 µm.The thermal annealing treatments of the as-prepared and implanted samples, done at temperatures of 300-500°C and in time steps of 2-4-8-16-32 h, yielded changes in the elemental distribution and phase composition, which could be followed in the top surface layers of approximately 300 nm using conversion electron Mössbauer spectroscopy (CEMS) and for a surface depth down to 30 µm, by g-ray Mössbauer spectroscopy in the scattering geometry (g-BMS). Complementary results were obtained from glancing-angle X-ray diffraction.

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“…The c N -phase is characterized by a very high hardness up to 1500 HV and therefore is of interest for protection of steels against wear and abrasion, different nitriding procedures have been put forward for generating a thin hard layer [1 -7]. But if the c N -layer becomes thicker, as in this case of gas corrosion, its formation leads to high lateral stresses, due to the great volume expansion of 26% in relation to the stainless steel [4]. These stresses will cause bursting off of scales containing this phase, from the outside of the steel tubes, i.e.…”

Section: Thermodynamic and Kinetic Considerationsmentioning

confidence: 99%

A case of nitridation, carburization and oxidation on a stainless steel

Grabke

2005

Materials and Corrosion

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A case of corrosion was studied on stainless steel tubes, exposed to a nitriding, carburizing and oxidizing environment (mainly NH 3 and CO 2 ) at 390 -450 8C. Due to the high nitriding potential prior formation of internally nitrided layers occurs, at higher temperatures (> about 425 8C) under precipitation of CrN in the layer and at lower temperatures under formation of the c N -phase, i.e. austenite with high N-content and expanded lattice. The latter process causes more severe corrosion, due to the high expansion, the stresses in the nitrided layers lead to bursting and repeated spalling of the scales. Carburization and oxidation are less important. The carburization is slower than nitridation, Fe 3 C formation is observed and carbon deposition. Also the oxidation by CO 2 is slow and converts the nitrides and carbides formed before, to unprotective oxide flakes.

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Relative roles of ion energy, ion flux, and sample temperature in low-energy nitrogen ion implantation of FeCrNi stainless steel

Cited by 97 publications

References 7 publications

Enhanced Carbon Diffusion in Austenitic Stainless Steel Carburized at Low Temperature

Enhanced Carbon Diffusion in Austenitic Stainless Steel Carburized at Low Temperature

Changes in austenitic steel surface induced by thermal and implantation treatments studied by Mössbauer spectroscopy

A case of nitridation, carburization and oxidation on a stainless steel

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