Hollow cathodic plasma source nitriding of AISI 4140 steel

Li, Yang; Bi, Yunjie; Zhang, Minyi; Zhang, Shangzhou; Gao, Xuepeng; Zhang, Zhehao; He, Yongyong

doi:10.1080/02670844.2020.1758012

Cited by 18 publications

(10 citation statements)

References 27 publications

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“…The surface roughness (94.0 nm) of the CPN sample is higher than that of the HCPSN sample (73.3 nm). Our previously reported that the microscale surface roughness of the polished sample is about 6.1 nm 27 . The highest peak of the CPN sample is approximately 400 nm, the lowest peak is approximately -150 nm, and the maximum peak difference is 550 nm.…”

Section: Resultsmentioning

confidence: 92%

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Mechanical and Wear Properties of 42CrMo Steel by Plasma Nitriding assisted Hollow Cathode Ion Source

et al. 2021

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Plasma nitriding is a plasma-activated thermochemical method widely used to increase the fatigue strength, hardness and wear resistance of low-alloy steels. In this work, a new structure consisting of a hollow cathode metal plate can produce a hollow cathode discharge and heat the workpiece by radiation. This principle is used to perform hollow cathode source plasma nitriding (HCSPN). Herein, 42CrMo steels were treated by conventional plasma nitriding (CPN) and HCSPN treatments. The 42CrMo steels were nitrided at 525 °C for 6 h in NH 3 atmosphere. The mechanical and dry wear properties were measured by nano-indentation, Vickers micro-indentation and ball-on-disk tribometer, respectively. The H 3 /E ⁎2 ratio was 0.0274 GPa (H=11.51 GPa and E ⁎ =235.84 GPa) for the CPN sample and 0.0276 GPa (H=10.87 GPa and E ⁎ =215.54 GPa) for the HCSPN sample. Compared with the untreated 42CrMn steel, all the nitrided samples possess increased fracture toughness. Because the workpiece was not used as a discharge cathode, this HCSPN treatment overcame the disadvantages of the conventional CPN treatment. Additionally, results showed that the surface of the HCSPN sample was smoother than that of the CPN sample, and its tribological performance was better.

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Section: Resultsmentioning

confidence: 92%

“…CPN and HCSPN treatments were conducted in an LDMC-20 pulsed plasma reactor 27 . The pulsed frequency of adopted pulse generator was 1000 Hz and pulse duty factor were 65~70%.…”

Section: Methodsmentioning

confidence: 99%

Mechanical and Wear Properties of 42CrMo Steel by Plasma Nitriding assisted Hollow Cathode Ion Source

et al. 2021

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“…Recently, the hollow-cathode effect has been used to enhance the impact of plasma diffusion. This effect can increase the plasma density in a furnace, significantly improving diffusion efficiency and the depth of diffusion layers [6,7]. Further, the electric potential of a sample affects the diffusion layer characteristics.…”

Section: Introductionmentioning

confidence: 99%

Simulation of hollow-cathode-nitriding plasma and design of diffusion equipment with DC and RF dual discharge

Zhang¹,

Wang²,

Shao³

et al. 2023

Phys. Scr.

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The formation and diffusion of plasma are complex and critical processes in plasma nitriding. A stable and high-concentration plasma atmosphere can effectively increase the diffusion rate and the thickness of the diffusion layer. In this study, a two-dimensional multi-physics model integrating physical kinetics, energy transfer, mass transfer, and electromagnetic induction was developed. The effect of a hollow-cathode structure on plasma distribution was investigated, and the edge effect observed on nitrided metals was eliminated. The impacts of the essential plasma diffusion parameters were simulated using the developed model. A simple but effective experiment was designed to validate the model. A diffusion furnace with DC and RF dual discharge was designed by adding a high-frequency coil to existing equipment. Subsequently, the effects of the two plasma excitation sources on the overall distribution of plasma were analyzed. Notably, the proposed model is a high-fidelity one based on actual device dimensions; therefore, it can be used to simulate, predict, and control the plasma formation process in the diffusion furnace. In addition, the model can provide reference data and guidance for optimizing the diffusion process and structural design of diffusion furnaces.

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“…Conventional plasma nitriding is considered a highly promising process to modify the surface of metal parts [16][17][18][19][20]. If the temperature is lower than 450 °C, a nitrided layer containing ɛÀ Fe 2-3 N and γ'À Fe 4 N phases and nitrogen-expanded martensite (α N ) is formed [21,22].…”

Section: Introductionmentioning

confidence: 99%

Effect of electric potentials on high‐temperature plasma nitriding of 2Cr13 stainless steel with active screen assisted

Shao

Wang

Zhang

et al. 2022

Materialwissenschaft Werkst

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The influence of electric potentials on the characteristics of modified layers with plasma nitriding of 2Cr13 stainless steel at a high temperature was investigated. Three active screens were placed on the cathodic plate. Three groups of 2Cr13 stainless steel samples were set with cathodic, anodic, and floating potentials. Samples were nitrided at 500 °C for 5 h in an ammonia atmosphere. The treated samples were analyzed using x‐ray diffraction, scanning electron microscopy with energy dispersive x‐ray spectroscopy, surface roughness tester, and atomic force microscopy. It is proved that nitriding treatments can be suitably carried out at three electric potentials, but the corresponding modified layers take on different microstructure, morphology, and hardness behaviors. It found that the three nitrided samples are mainly composed of the ϵ−Fe2‐3N and γ’−Fe4N phases. The order of thicknesses of the nitrided layers is: floating < anodic < cathodic potential. The results also demonstrated that electric potentials play essential roles in the corrosion resistance and tribological properties in plasma nitriding treatment. Because there is no visible precipitation of chromium nitride in the modified layer, the corrosion resistance of the floating nitrided sample is better than that of the other two samples.

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Hollow cathodic plasma source nitriding of AISI 4140 steel

Cited by 18 publications

References 27 publications

Mechanical and Wear Properties of 42CrMo Steel by Plasma Nitriding assisted Hollow Cathode Ion Source

Mechanical and Wear Properties of 42CrMo Steel by Plasma Nitriding assisted Hollow Cathode Ion Source

Simulation of hollow-cathode-nitriding plasma and design of diffusion equipment with DC and RF dual discharge

Effect of electric potentials on high‐temperature plasma nitriding of 2Cr13 stainless steel with active screen assisted

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