Influence of bias voltage on the formation and properties of iron-based nitrides produced by plasma nitriding

Li, Yang; Wang, Liang; Zhang, Dandan; Shen, Lie

doi:10.1016/j.jallcom.2010.03.027

Cited by 36 publications

(8 citation statements)

References 20 publications

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“…Since the workpiece is not acting as the cathode anymore, the edge effect and the hollow cathode effect are eliminated; however, in the case of ASPN, the heating time maybe longer. In order to reduce the heating time back to the DCPN process time, a lower voltage (bias voltage) than the active screenÕs is applied to the sample (Ref 9,19); this process is the so-called active screen-biased plasma nitriding process (ASBPN). The application of bias is an extended option of the ASPN process especially in the industry, in order to obtain homogeneous heating of a large number of parts.…”

Section: Introductionmentioning

confidence: 99%

Effects of Different Variants of Plasma Nitriding on the Properties of the Nitrided Layer

Kovács

Quintana

Dobránszky³

2019

J. of Materi Eng and Perform

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Several process variants of plasma nitriding can be distinguished depending on the location of the voltage introduction. The aim of this study is to compare three different variants of plasma nitriding (DC plasma nitriding, active screen plasma nitriding, and active screening process with bias voltage application) extended by the study of the coverage of active screen on C45E unalloyed steel, using two different N 2-H 2 gas mixtures. The thickness of the compound layer was measured using a scanning electron microscope, the phase analysis was performed by an x-ray diffractometer, and the nitrogen contents were analyzed by glow discharge optical electron spectroscopy. The results showed that the layer thickness and the surface hardness were higher by using active screen-biased plasma nitriding with high N 2 content gas mixture. Besides, the lid of the active screen did not influence significantly the chemical composition of the compound layer.

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Section: Introductionmentioning

confidence: 99%

Effects of Different Variants of Plasma Nitriding on the Properties of the Nitrided Layer

Kovács

Quintana

Dobránszky³

2019

J. of Materi Eng and Perform

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“…However, for obtaining the effective thickness of nitrided layer, the nitriding temperature or holding time must be increased [10][11][12], which would bring out porosity in the nitrided layer, thus may results in side effect on the surface hardness and wear resistance. It has been reported that preoxidation can enhance the nitriding efficiency, since a thin oxide layer is formed during preoxidation process, which can be decomposed during the followed nitriding process [13,14]. Traditionally, preoxidation process is conducted in air furnace before salt bath nitriding [15,16].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Salt Bath Preoxidation and Air Preoxidation for Salt Bath Nitriding

Mei

Dai

et al. 2019

Acta Metall Slovaca

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<p class="AMSmaintext1">Salt bath preoxidation was primarily conducted prior to salt bath nitriding, and the effect on salt bath nitriding was compared with that of conventional air preoxidation. Characterization of the modified surface layer was made by means of optical microscopy, scanning electron microscope (SEM), micro-hardness tester and x-ray diffraction (XRD). The results showed that the salt bath preoxidation could significantly enhance the nitriding efficiency. The thickness of compound layer was increased from 13.3μm to 20.8μm by salt bath preoxidation, more than 60% higher than that by conventional air preoxidation under the same salt bath nitriding parameters of 560℃ and 120min. Meanwhile, higher cross-section hardness and thicker effective hardening layer were obtained by salt bath preoxidation, and the enhancement mechanism of salt bath preoxidation was discussed.</p>

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“…9) Recently, considerable interest has been paid to alternative nitriding processes such as active screen plasma nitriding (ASPN), through-cage plasma nitriding, and cathodic-cage plasma nitriding. [10][11][12][13][14][15][16][17][18][19][20] These processes offer the advantage of completely eliminating the edge effect associated with conventional plasma nitriding processes, as the plasma is produced on the screen and not directly on the samples. [10][11][12][13] These processes can be used to treat polymers that are nonconductive materials.…”

Section: Introductionmentioning

confidence: 99%

Effect of Screen Open Area on Active Screen Plasma Nitriding of Austenitic Stainless Steel

2014

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Austenitic stainless steel SUS 316L was nitrided by active screen plasma nitriding (ASPN) using screens with various open areas to investigate the effect of the screen's open area ratio on the nitriding response. The sample was placed on the sample stage in a floating potential and isolated from the cathodic screen and anode. The screen, which was SUS 316L expanded metal mesh with 38%, 48%, or 63% open area ratio, was mounted on the cathodic stage around the sample stage. Nitriding was performed in a nitrogen-hydrogen atmosphere with 25% N2 + 75% H2 for 18 ks at 693 K under 600 Pa by the ASPN process. After nitriding, the nitrided microstructure was examined using a scanning electron microscope and an electron probe microanalyzer. The phase structures on the nitrided surface were determined by X-ray diffraction. In addition, the surface hardness and cross section of the nitrided samples were measured by the use of a Vickers microhardness tester. The thickness of the nitrided layer of the S-phase decreased with increasing open area ratio of the screen.KEY WORDS: surface engineering; active screen plasma nitriding; cathodic cage; S-phase; stainless steel; open area ratio.

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Influence of bias voltage on the formation and properties of iron-based nitrides produced by plasma nitriding

Cited by 36 publications

References 20 publications

Effects of Different Variants of Plasma Nitriding on the Properties of the Nitrided Layer

Effects of Different Variants of Plasma Nitriding on the Properties of the Nitrided Layer

Comparison of Salt Bath Preoxidation and Air Preoxidation for Salt Bath Nitriding

Effect of Screen Open Area on Active Screen Plasma Nitriding of Austenitic Stainless Steel

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