Thermal stability and phase decomposition of nitrided layers on 316L and 310 austenitic stainless steels

Djellal, R.; Saker, A.; Bouzabata, B.; Mekki, D.E.

doi:10.1016/j.surfcoat.2017.07.014

Cited by 22 publications

(13 citation statements)

References 31 publications

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“…On the bottom of CrN coating, an N-rich layer formed due to outward diffusion of N from the underlying nitrided steel, which is expected to occur at temperatures higher than 550 • C [33]. Due to the increased N content, a stoichiometric CrN was formed.…”

Section: Chemical Composition and Microstructure After Casting Experimentioning

confidence: 99%

Metallurgical Soldering of Duplex CrN Coating in Contact with Aluminum Alloy

et al. 2020

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Coatings deposited by physical vapor deposition (PVD) significantly reduce the wear of high pressure die casting tools; however, cast alloy soldering still has a strong negative effect on production efficiency. Although a lot of research has been already done in this field, the fundamental understanding of aluminum alloy soldering toward PVD coatings is still scarce. Therefore, in this work the performance of CrN duplex coatings with different roughness is evaluated by a modified ejection test performed with delayed (DS) and conventional casting solidification (CS). After the ejection tests, sample surfaces and layers were subjected to comprehensive characterizations of their morphological and chemical characteristics. Considerably lower values of the ejection force were recorded in DS experiments than in CS experiments. Surface roughness played an important role in the CS experiments, while samples with different surface topographies in the DS experiments performed in a similar fashion. The decrease in the ejection force, observed in DS tests, is attributed to the formation of a thick Cr–O layer on CrN coating which reduced soldering and sliding friction against thick Al–O casting scale. The Cr–O layer formed in DS experiments suffered from diffusion wear by cast alloy. The observed oxidation phenomena of nitride coatings may be utilized in a design of non-sticking coatings.

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Section: Chemical Composition and Microstructure After Casting Experimentioning

confidence: 99%

Metallurgical Soldering of Duplex CrN Coating in Contact with Aluminum Alloy

et al. 2020

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“…The Ⅲ layer also was divided into a porous compound layer and a transition layer (Figure 5b-e). The surface of a nitrided alloy is the place with the highest nitrogen concentration [26]. In the nitriding process, an Ni coating not only protects pure iron from being oxidized by the trace oxygen in the atmosphere, but also serves as a catalyst to decompose absorbed ammonia, thus promoting nitriding efficiency [18].…”

Section: Microscopic Morphologymentioning

confidence: 99%

“…In previous studies, Yin et al pointed out that catalytic decomposition of ammonia by Ni was better than Fe [30]. Compared with a pure iron surface, an Ni coating composed of nanoparticles could increase the specific surface area of the entire sample and the amount The surface of a nitrided alloy is the place with the highest nitrogen concentration [26]. In the nitriding process, an Ni coating not only protects pure iron from being oxidized by the trace oxygen in the atmosphere, but also serves as a catalyst to decompose absorbed ammonia, thus promoting nitriding efficiency [18].…”

Section: Microscopic Morphologymentioning

confidence: 99%

The Controlled Compound Layer of Ni-Coated Nitrided Pure Iron

Shen

Zhang

et al. 2020

Nanomaterials

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In order not to sacrifice nitrided layer thickness and reduce brittle compound layer thickness, Ni-coated pretreatment was carried out with electrodeposition on a pure iron surface, followed by gas nitriding. The brittle compound layer thickness of duplex surface treated samples was reduced, and the nitrided layer thickness increased to 320 μm. The microhardness was 4 times harder, and the wear loss was reduced by 68% compared with the original material. The results indicate that Ni-coated pretreatment could effectively improve microhardness and wear resistance and realize the controlled microstructure of a brittle compound layer of pure iron without compromising nitrided layer thickness. Ni coating plays an important role in ammonia adsorption and decomposition, and in the transfer of active nitrogen atoms during nitriding.

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“…A hard layer of nitrides forms, as well as a nitrogen diffusion region within the microstructure of the steel [5,6]. The main resulting properties from nitriding are: high surface hardness and wear resistance, resistance to fatigue, corrosion resistance and softening resistance (up to the temperature of the nitriding process) [5][6][7][8][9][10][11][12]. Deep cryogenic treatment (DCT) is a thermal treatment that subjects the workpiece to time-controlled cryogenic temperatures, typically -196°C at its coldest.…”

Section: Introductionmentioning

confidence: 99%

Wear resistance of the pressure armor submitted to deep cryogenic treatment and plasma nitriding

Herrera

Muterlle

2018

J Braz. Soc. Mech. Sci. Eng.

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Risers are multilayer structures used in oil production and transportation. The pressure armor is the layer responsible for supporting the internal radial pressure and is produced from a helical interlocked steel wire. The interlocking mechanism, which gives flexibility to the riser, is responsible for the wear on the pressure armor, resulting in a micro-abrasive wear. The present work aims to study the effect of deep cryogenic treatment and plasma nitriding on the micro-abrasive wear in the pressure armor. Samples tested were taken from the contact region of the pressure armor. The micro-abrasive wear test was performed on a free ball machine. The tests were conducted on the samples as received, with deep cryogenic treatment and with plasma nitriding (at 515°C for 8, 24 and 48 h). It was observed that the material with deep cryogenic treatment had a Vickers microhardness profile and wear coefficient similar to the sample as received. The nitrided samples showed a higher (21.8%, 23.2% and 29%) microhardness value at the surface region than the sample as received and an improvement in wear coefficient in the transient (29.85%, 28.53% and 29.81%) and permanent (19.18%, 25.19% and 28.09%) regions.

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Thermal stability and phase decomposition of nitrided layers on 316L and 310 austenitic stainless steels

Cited by 22 publications

References 31 publications

Metallurgical Soldering of Duplex CrN Coating in Contact with Aluminum Alloy

Metallurgical Soldering of Duplex CrN Coating in Contact with Aluminum Alloy

The Controlled Compound Layer of Ni-Coated Nitrided Pure Iron

Wear resistance of the pressure armor submitted to deep cryogenic treatment and plasma nitriding

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