Evaluation of the formation of compound coatings on aluminium by the new method of active screen plasma nitriding

The paper presents the structural characterization of γ′-Fe4N nitrides produced by active screen plasma nitriding (ASPN) processes. Experiments were performed on the Fe-Armco model material at 693, 773, and 853 K for 6 h. Investigation of the properties of the substrate was realized using scanning electron microscopy (SEM, SEM–EBSD/Kikuchi lines), energy-filtered transmission electron microscopy (TEM-EFTEM), X-ray diffraction (GID, grazing incidence diffraction, micro-XRD), and secondary ion mass spectroscopy (SIMS). Results have confirmed that the γ′-Fe4N nitrides’ structure and morphology depend considerably on the nitriding process’s plasma conditions and cooling rate. In addition to that, γ′-Fe4N nitrides’ formation can be correlated with the surface layer saturation mechanism and recombination effect. It has been shown that the γ′-Fe4N structure depends considerably on several phenomena that occur in the diffusive layer (e.g., top layer decomposition, nitrogen, and carbon atoms’ migration). Our research proves that the nitrogen concentration gradient is a driving force of nitrogen migration atoms during the recombination of γ′-Fe4N nitrides. Finally, realized processes have allowed us to optimize active screen plasma nitriding to produce a surface layer of fine nitrides.

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Active screen plasma nitriding of 316 stainless steel for the application of bipolar plates in proton exchange membrane fuel cells

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2014.04.102 ◽

2014 ◽

Vol 39 (36) ◽

pp. 21470-21479 ◽

Cited By ~ 40

Author(s):

Kaijie Lin ◽

Xiaoying Li ◽

Yong Sun ◽

Xia Luo ◽

Hanshan Dong

Keyword(s):

Stainless Steel ◽

Fuel Cells ◽

Proton Exchange Membrane ◽

Plasma Nitriding ◽

Proton Exchange ◽

Bipolar Plates ◽

316 Stainless Steel ◽

Active Screen Plasma Nitriding ◽

Exchange Membrane ◽

Active Screen

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Simultaneous duplex process of TiN coating and nitriding by active screen plasma nitriding

Surface and Coatings Technology ◽

10.1016/j.surfcoat.2012.04.021 ◽

2013 ◽

Vol 228 ◽

pp. S558-S562 ◽

Cited By ~ 29

Author(s):

Akio Nishimoto ◽

Hiroaki Nii ◽

Ryota Narita ◽

Katsuya Akamatsu

Keyword(s):

Plasma Nitriding ◽

Tin Coating ◽

Active Screen Plasma Nitriding ◽

Duplex Process ◽

Active Screen

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Active Screen Plasma Nitriding Efficiency and Ecology

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.657.369 ◽

2014 ◽

Vol 657 ◽

pp. 369-373 ◽

Cited By ~ 5

Author(s):

Cătălin Andrei Țugui ◽

Mihai Axinte ◽

Carmen Nejneru ◽

Petrică Vizureanu ◽

Manuela Cristina Perju ◽

...

Keyword(s):

Stainless Steels ◽

Plasma Nitriding ◽

Direct Application ◽

Hollow Cathodes ◽

Active Screen Plasma Nitriding ◽

Industrial Solution ◽

Negative Environmental Impact ◽

Quality Surface ◽

Made In ◽

Active Screen

Plasma nitriding has significant advantages: very low running costs (reduced consumption of energy and gases); optimized structure and layers; and nitriding of stainless steels. Plasma nitriding is totally safe and has no poisonous gas emissions and no negative environmental impact. However, conventional plasma nitriding has a number of well-known difficulties, including the direct application of plasma on the parts to be treated, the risk of arcing, hollow cathodes, white layers, non-homogenous batch temperature and the impossibility to mix parts of different geometries in the chamber made this technology to be almost forgotten. In the last years, due to the ecofriendly character of the technology, several atempts were made in order to establish an improvement in this technique in terms of batch damages. Active screen plasma nitriding technology is a new industrial solution that enjoys all the advantages of traditional plasma nitriding but does not have its inconveniences. A comparative study regarding quality surface and formed layer properties between conventional plasma nitriding and active screen plasma nitriding was conducted, in order to highlight the advantages that comes with this relatively new technique.

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