Investigation of admixed gas effect on plasma nitriding of AISI316L austenitic stainless steel

Ohtsu, Naofumi; Miura, Koyo; Hirano, Mitsuhiro

doi:10.1016/j.vacuum.2021.110545

Cited by 17 publications

(4 citation statements)

References 25 publications

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“…A thin layer of what seems to be Cr 2 O 3 with a thickness less than 2.0 µm was observed for the pre-oxidized specimen. According to different authors, the use of H 2 improves the diffusion of the nitrogen atom to diffuse into the crystalline network of the steel [24,25]. Moskalioviene and Galdikas [26] showed that the addition of H 2 to the N 2 discharge in a concentration interval of 30 and 40% improves the penetration of nitrogen in 304 type stainless steel.…”

Section: Sem Characterizationmentioning

confidence: 99%

Effect of Plasma Nitriding and Oxidation on the Corrosion Resistance of 304 Stainless Steel in LiBr/H2O and CaCl2-LiBr-LiNO3-H2O Mixtures

Larios-Galvez

Vázquez‐Vélez

Martı́nez

2023

Metals

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The effect of plasma nitriding and oxidation on the corrosion resistance of AISI 304 type stainless steel in LiBr/H2O and CaCl2-LiBr-LiNO3-H2O mixtures at 80 °C has been evaluated by using potentiodynamic polarization curves and electrochemical impedance spectroscopy techniques (EIS). Steel was plasma treated at 500 °C during 8 h under different atmospheres, nominally 20% N2 + 80% H2, 100% N2 and 100% O2. X-ray diffraction analysis (XRD) showed the presence of a CrN layer in nitrided specimens, whereas scanning electronic microscopy analysis revealed that specimen treated in the 20% N2 + 80% H2 atmosphere showed the thickest nitride layer. Specimens nitrided in the 20% N2 + 80% H2 atmosphere had the noblest open circuit potential value in both solutions, whereas potentiodynamic polarization curves indicated the formation of a passive layer. These specimens exhibited the lowest corrosion and passivation current density values. Corrosion process was under charge transfer control in both solutions regardless of the plasma treatment. The type of corrosion suffered by the steel under all treatments was the pitting type of corrosion. Pits density was the lowest for nitrides steels rather than that for untreated or pre-oxidized ones.

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Section: Sem Characterizationmentioning

confidence: 99%

Effect of Plasma Nitriding and Oxidation on the Corrosion Resistance of 304 Stainless Steel in LiBr/H2O and CaCl2-LiBr-LiNO3-H2O Mixtures

Larios-Galvez

Vázquez‐Vélez

Martı́nez

2023

Metals

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“…The thicker S-phase layer requires a long-time nitriding treatment at low temperature. Obviously, it is hard to fabricate a thick S-phase layer by simply increasing nitriding temperature, prolonging nitriding duration as well as optimizing gas mixtures [10,11], since there is a limit of temperature and time for the nitriding of ASS, that is, the threshold T-t curve [12]. This reminds us how the S-phase layer without precipitates can be obtained only when the nitriding temperature and time lie below the threshold T-t curve.…”

Section: Introductionmentioning

confidence: 99%

High-Efficient Gas Nitridation of AISI 316L Austenitic Stainless Steel by a Novel Critical Temperature Nitriding Process

Tang,

Zhang,

Zhan

et al. 2023

Coatings

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To improve the surface properties of austenitic stainless steels, a thick S-phase layer was prepared by using a novel critical temperature nitriding (CTN) process. The properties of the thick S-phase layer were optimized by controlling the process parameters. The microstructures and phase compositions of CTN-treated layers were characterized by the optical microscope, scanning electron microscope and X-ray diffraction, respectively. The surface properties, including corrosion and wear resistance, were systematically investigated by the electrochemical workstation, micro-hardness tester and ball-on-disk tribometer, respectively. The results showed that a thick S-phase layer with a thickness of 18 to 25 μm can be fabricated in a short time by critical temperature nitriding, which represented higher efficiency than conventional low-temperature nitriding. Although the most top surfaces of CTN-treated layers contain massive iron nitrides, there are no precipitates in the inner nitrided layer. The electronic work function calculated by first-principles method has confirmed that those iron nitrides had a slight influence on the corrosion resistance of nitrided layers. The optimized CTN-treated layer exhibited a comparable corrosion resistance and wear resistance as the low-temperature nitrided layer. The CTN process is considered a potentially highly efficient surface modification method for austenitic stainless steels.

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“…In addition, in high-alloy steels, there is a reduction in the hardening depth after nitriding treatment due to the precipitation of alloy nitrides, which additionally limits the diffusion of nitrogen to the substrate [47]. Plasma nitriding is one of the modern techniques of thermo-chemical treatment, which is usually carried out with the use of nitrogen and hydrogen [48][49][50][51][52]. The process is carried out under reduced pressure where a voltage is applied between the samples and the walls of the furnace.…”

Section: Introductionmentioning

confidence: 99%

“…The process is carried out under reduced pressure where a voltage is applied between the samples and the walls of the furnace. A glow discharge with a high level of ionization (plasma) is Plasma nitriding is one of the modern techniques of thermo-chemical treatment, which is usually carried out with the use of nitrogen and hydrogen [48][49][50][51][52]. The process is carried out under reduced pressure where a voltage is applied between the samples and the walls of the furnace.…”

Section: Introductionmentioning

confidence: 99%

Effect of Machine Pin-Manufacturing Process Parameters by Plasma Nitriding on Microstructure and Hardness of Working Surfaces

Dudziński,

Medyński,

Sacher

2023

Crystals

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This work concerns two stages of research into plasma nitriding (change of nitriding steel and modification of nitriding parameters). In the first stage, pins obtained from currently used steel were compared with pins made of an alternative material available on the market, using the same nitriding process parameters. As a result of the metallographic tests carried out, in the first case, the presence of a thin, porous, and heterogeneous nitrided layer or its absence was found, with the core in its raw state and not thermally improved. In the second case, the presence of a nitrided layer of small thickness with noticeable porosity on the surface of the sample was found, but with a core after heat treatment (incorrect process parameters). Therefore, modification of the parameters of the nitriding process was proposed, in terms of a mixture of gases, currents, time, and temperature of the nitriding process. As a result, a satisfactory effective thickness of the nitrided layer was obtained, consisting of a white near-surface zone with ε and ε + γ′-type nitrides with a thickness of 8.7 to 10.2 µm, and a dark zone of internal nitriding with γ′ nitrides. The nitrides layer was continuous, compact, and well adhered to the steel surface. In the core of the samples, the presence of a fine-needle tempering sorbite structure with a small amount of fine bainite, which is correct for the steel after heat treatment and nitriding, was found. The most favorable parameters of the ion nitriding process were gas flow rate (1.5 L/min N; 0.4 L/min H; 0.3 L/min Ar); currents (BIAS—410 V 4.0 A, SCREEN—320 V 4.0 A); time (26 h and 35 min); and temperature (550 °C).

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Investigation of admixed gas effect on plasma nitriding of AISI316L austenitic stainless steel

Cited by 17 publications

References 25 publications

Effect of Plasma Nitriding and Oxidation on the Corrosion Resistance of 304 Stainless Steel in LiBr/H2O and CaCl2-LiBr-LiNO3-H2O Mixtures

Effect of Plasma Nitriding and Oxidation on the Corrosion Resistance of 304 Stainless Steel in LiBr/H2O and CaCl2-LiBr-LiNO3-H2O Mixtures

High-Efficient Gas Nitridation of AISI 316L Austenitic Stainless Steel by a Novel Critical Temperature Nitriding Process

Effect of Machine Pin-Manufacturing Process Parameters by Plasma Nitriding on Microstructure and Hardness of Working Surfaces

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