Effect of CH4 addition on plasma nitrocarburizing of austenitic stainless steel

Chen, Fan-Shiong; Chang, Chih-Neng

doi:10.1016/s0257-8972(02)00842-3

Cited by 37 publications

(4 citation statements)

References 13 publications

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“…This maximum is marked with a star in Figures 2 to 5. The redistribution of carbon in the near surface region of plasma nitrided steels was discussed by several other authors [9][10][11][12]14,15 . This carbon peak concentration below the compound layer would be related to the formation of cementite, like precipitates in the grain boundaries 16 , which leads to lower toughness of the nitrided layer 12,13 .…”

Section: Microstructure Phase and Chemical Compositionmentioning

confidence: 99%

Metallurgical response of an AISI 4140 steel to different plasma nitriding gas mixtures

Skonieski

Santos

Hirsch³

et al. 2013

Mat. Res.

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Plasma nitriding is a surface modification process that uses glow discharge to diffuse nitrogen atoms into the metallic matrix of different materials. Among the many possible parameters of the process, the gas mixture composition plays an important role, as it impacts directly the formed layer's microstructure. In this work an AISI 4140 steel was plasma nitrided under five different gas compositions. The plasma nitriding samples were characterized using optical and scanning electron microscopy, microhardness test, X-ray diffraction and GDOES. The results showed that there are significant microstructural and morphological differences on the formed layers depending on the quantity of nitrogen and methane added to the plasma nitriding atmosphere. Thicknesses of 10, 5 and 2.5 µm were obtained when the nitrogen content of the gas mixtures were varied. The possibility to obtain a compound layer formed mainly by γ ' -Fe 4 N nitrides was also shown. For all studied plasma nitriding conditions, the presence of a compound layer was recognized as being the responsible to hinder the decarburization on the steel surface. The highest value of surface hardness -1277HV -were measured in the sample which were nitrided with 3vol.% of CH 4 .

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Section: Microstructure Phase and Chemical Compositionmentioning

confidence: 99%

Metallurgical response of an AISI 4140 steel to different plasma nitriding gas mixtures

Skonieski

Santos

Hirsch³

et al. 2013

Mat. Res.

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“…Therefore, modification of these surface properties is required, aiming at the reliable performance and long lifetime of the components manufactured from such steels. Low-temperature plasma-assisted thermochemical diffusion treatments such as plasma nitriding (PN) [1,2], plasma carburizing (PC) [3][4][5] and plasma nitrocarburizing (PNC) [6] can be effectively applied to improve the surface hardness and wear resistance of austenitic stainless steels without negatively affecting their high general corrosion resistance [7,8]. Moreover, it has been shown that the pitting corrosion resistance to a variety of chloride-containing media improved significantly compared to untreated steels [9,10].…”

Section: Introductionmentioning

confidence: 99%

The Interplay Effects between Feed-Gas Composition and Bias Plasma Condition during Active-Screen Plasma Nitrocarburizing with a Solid Carbon Source

et al. 2023

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Recent technological development of utilizing an active screen made of solid carbon for plasma-assisted thermochemical diffusion treatments opens up new possibilities for control over the in situ generated treatment environment to guarantee reproducible treatment conditions and material responses. Until now, the investigations of active-screen plasma nitrocarburizing (ASPNC) using an active screen manufactured from solid carbon focused on the influence of a single treatment parameter variation on the material response. In this systematic study, experiments were conducted to vary the H2-N2 feed-gas composition while varying the bias plasma power. The experiments served to better understand a simultaneous variation in the mentioned parameters on the resulting treatment environment and material response during ASPNC of AISI 316L austenitic stainless steel. Therefore, nitriding and carburizing effects in the expanded austenite layer can be obtained. It is shown that an increased nitriding effect, i.e., nitrogen diffusion depth and content, was achieved in case of biased conditions and for H2-N2 feed-gas compositions with higher N2 amounts. On the contrary, an increased carburizing effect, i.e., carbon diffusion depth and content, was achieved in nonbiased conditions, independent from the H2-N2 feed-gas composition.

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“…Plasma-assisted thermochemical diffusion treatment has drawn significant attention for its capacity to enhance the surface properties of stainless steels and its simple process implementation, low cost, and low environmental impact. Different plasmaassisted treatments, such as plasma nitriding (PN) [4,5], plasma carburizing (PC) [6,7], and plasma nitrocarburizing (PNC) [8,9], have been realized by introducing nitrogen-and/or carbon-containing precursor gases to the process atmosphere. Nevertheless, two main challenges for the thermochemical diffusion treatment of stainless steels can be pointed out: (i) the chromium oxide (Cr 2 O 3 ) passive layer preventing nitrogen and carbon atoms from diffusing into the stainless steel, and (ii) the chromium nitride and/or chromium carbide precipitation at elevated treatment temperatures/times, which in turn negatively affect the corrosion resistance [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Effects of Plasma-Chemical Composition on AISI 316L Surface Modification by Active Screen Nitrocarburizing Using Gaseous and Solid Carbon Precursors

Jafarpour

Pipa

Puth

et al. 2021

Metals

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Low-temperature plasma nitrocarburizing treatments are applied to improve the surface properties of austenitic stainless steels by forming an expanded austenite layer without impairing the excellent corrosion resistance of the steel. Here, low-temperature active screen plasma nitrocarburizing (ASPNC) was investigated in an industrial-scale cold-wall reactor to compare the effects of two active screen materials: (i) a steel active screen with the addition of methane as a gaseous carbon-containing precursor and (ii) an active screen made of carbon-fibre-reinforced carbon (CFC) as a solid carbon precursor. By using both active screen materials, ASPNC treatments at variable plasma conditions were conducted using AISI 316L. Moreover, insight into the plasma-chemical composition of the H2-N2 plasma for both active screen materials was gained by laser absorption spectroscopy (LAS) combined with optical emission spectroscopy (OES). It was found that, in the case of a CFC active screen in a biased condition, the thickness of the nitrogen-expanded austenite layer increased, while the thickness of the carbon-expanded austenite layer decreased compared to the non-biased condition, in which the nitrogen- and carbon-expanded austenite layers had comparable thicknesses. Furthermore, the crucial role of biasing the workload to produce a thick and homogeneous expanded austenite layer by using a steel active screen was validated.

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Effect of CH4 addition on plasma nitrocarburizing of austenitic stainless steel

Cited by 37 publications

References 13 publications

Metallurgical response of an AISI 4140 steel to different plasma nitriding gas mixtures

Metallurgical response of an AISI 4140 steel to different plasma nitriding gas mixtures

The Interplay Effects between Feed-Gas Composition and Bias Plasma Condition during Active-Screen Plasma Nitrocarburizing with a Solid Carbon Source

Effects of Plasma-Chemical Composition on AISI 316L Surface Modification by Active Screen Nitrocarburizing Using Gaseous and Solid Carbon Precursors

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