Modelling of layer development and nitrogen distribution on different microstructures during plasma nitriding

Bergelt, T; Landgraf, Pierre; Grund, Thomas; Bräuer, Günter; Lampke, Thomas

doi:10.1016/j.surfcoat.2022.128813

Cited by 10 publications

(3 citation statements)

References 25 publications

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“…The diffusion coefficients of nitrogen should not be assumed as a constant value in different phases. From the literature [42], it is equal to 5 × 10 −8 and 9 × 10 −10 -4 × 10 −9 mm 2 /s in γ'-Fe 4 N and ε-Fe 2-3 N at 470 • C, respectively. However, the PN using the RF-ICP source is also characterized by a surface sputtering as the bias potential (−80 V) was applied to the samples.…”

Section: Discussionmentioning

confidence: 91%

Duplex Treatment of AISI 420 Steel by RF-ICP Nitriding and CrAlN Coating Deposition: The Role of Nitriding Duration

2022

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The duplex treatment of AISI 420 steel samples by nitriding in a radiofrequency inductively coupled plasma (RF-ICP) discharge of Ar + N2 + H2 atmosphere followed by CrAlN coating deposition was performed in this study. The influence of plasma nitriding (PN) duration (10, 20, 40, and 60 min) on the structural and functional properties of the duplex-treated samples was determined. A non-linear dependence of AISI 420 steel nitriding kinetics was found on the square root of the PN duration. The thicknesses of the compound layer (CL) and nitrogen diffusion zone (DZ) in the samples and their phase composition resulted in different critical loads of coating failures under adhesion tests. Increasing the load-bearing capacity by the PN caused coating hardening in duplex-treated samples. The role of the PN duration on the wear characteristics of the AISI 420 steel samples after the duplex treatment has been discussed. Corrosion tests of AISI 420 steel demonstrated the significant enhancement (5–67 times) of its corrosion resistance in a 3.5 wt.% NaCl solution after duplex treatment.

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Section: Discussionmentioning

confidence: 91%

Duplex Treatment of AISI 420 Steel by RF-ICP Nitriding and CrAlN Coating Deposition: The Role of Nitriding Duration

2022

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“…One of the reasons for the higher hardness of the nitrided surface after plasma nitriding is again the longer process time, during which the surface is more intensively saturated with nitrogen and the compound layer containing the phase γ (Fe 4 N) + ε (Fe 2-3 N) is formed and the diffusion layer is strengthened. As the ε/γ ratio increases, the surface hardness increases [33,34]. The degree of supersaturation of the surface adsorption layer is exponentially related to temperature and depends on the time of the process and the saturation potential of the environment.…”

Section: Evaluation Of the Depth Of The Diffusion Layermentioning

confidence: 99%

Change in Dimensions and Surface Roughness of 42CrMo4 Steel after Nitridation in Plasma and Gas

et al. 2022

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The influence of plasma nitriding and gas nitriding processes on the change of surface roughness and dimensional accuracy of 42CrMo4 steel was investigated in this paper. Both processes almost always led to changes in the surface texture. After plasma nitriding, clusters of nitride ions were formed on the surface of steel, while gas nitriding very often led to the new creation of a formation of a “plate-like” surface texture. In both cases of these processes, a compound layer in specific thickness was formed, although the parameters of the processes were chosen with the aim of suppressing it. After the optimizing of nitriding parameters during nitriding processes, it was found that there were no changes in the surface roughness evaluated using the Ra parameter. However, it turned out that when using a multi-parameter evaluation of roughness (the parameters Rz, Rsk and Rku were used), there were presented some changes in roughness due to nitriding processes, which affect the functional behavior of the components. Roughness changes were also detected by evaluating surface roughness profiles, where nitriding led to changes in peak heights and valley depths. Nitriding processes further led to changes in dimensions in the form of an increase of 0.032 mm on average. However, the magnitude of the change has some context on chemical composition of material. A larger increase in dimensions was found with gas nitriding. The change in the degree of IT accuracy is closely related to the change in dimension. For both processes, there was a change of one degree of IT accuracy compared to the ground part (from IT8 to IT9). On the basis of the achieved dimensional accuracy results, a coefficient of change in the degree of accuracy IT was created, which can be used to predict changes in the dimensional accuracy of ground surfaces after nitriding processes in degrees of accuracy IT3–IT10. In this study, a tool for predicting changes in degrees of accuracy of ground parts after nitriding processes is presented.

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“…During this process, nitrogen diffuses into the tool's surface layer and forms hard nitrides. The formation of nitrides is influenced by process parameters, such as the nitrogen content [9]. A high nitrogen content can lead to the formation of a compound layer that has a higher hardness than the diffusion zone [10] and can reduce adhesive wear according to Terres et.…”

Section: Introductionmentioning

confidence: 99%

Metal-Containing Diamond-Like Carbon Coatings with Increased Temperature Stability for Wear Protection of Nitrided Hot Forging Dies

Behrens,

Bräuer,

Brunotte

et al. 2023

MSF

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In cold forging processes, diamond-like carbon (DLC) coatings have become established as a wear protection for forging dies, featuring high hardness and advantageous friction properties. This counteracts the particular critical abrasive tool wear and increases tool life. A major disadvantage of DLC coatings is their low thermal stability. In this study, the influence of metallic elements (niobium, tungsten and chromium) in the treatment atmosphere of the coating process is investigated with the aim of increasing the temperature resistance of the DLC coating and enabling its application as a wear-protection measure for hot forging dies. Preliminary studies were carried out to investigate the influence of different treatment atmospheres on wear-reducing properties such as high hardness and coating adhesion depending on prior nitriding processes. The most promising metal-doped DLC coating, with 30 % tungsten in the treatment atmosphere, was used in serial forging tests. At a blank temperature of 1,200 °C and a moderate count of 100 forging cycles, wear was reduced by up to 60 % compared to the nitrided reference tool.

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Modelling of layer development and nitrogen distribution on different microstructures during plasma nitriding

Cited by 10 publications

References 25 publications

Duplex Treatment of AISI 420 Steel by RF-ICP Nitriding and CrAlN Coating Deposition: The Role of Nitriding Duration

Duplex Treatment of AISI 420 Steel by RF-ICP Nitriding and CrAlN Coating Deposition: The Role of Nitriding Duration

Change in Dimensions and Surface Roughness of 42CrMo4 Steel after Nitridation in Plasma and Gas

Metal-Containing Diamond-Like Carbon Coatings with Increased Temperature Stability for Wear Protection of Nitrided Hot Forging Dies

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