Hydrogen behavior in the iron surface layer modified by plasma nitriding and ion boronising

2000 ◽  
Vol 51 (12) ◽  
pp. 841-849 ◽  
Author(s):  
E. Lunarska ◽  
J. Michalski
Keyword(s):  
Surface Layer ◽  
Plasma Nitriding ◽  
Iron Surface

scholarly journals Structural Characterization of Fine γ′-Fe4N Nitrides Formed by Active Screen Plasma Nitriding

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1656
Author(s):  
Jaroslaw Jan Jasinski ◽  
Lukasz Kurpaska ◽  
Tadeusz Fraczek ◽  
Malgorzata Lubas ◽  
Maciej Sitarz
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Characterization ◽  
Plasma Nitriding ◽  
Nitrogen Concentration ◽  
Grazing Incidence ◽  
Model Material ◽  
Active Screen Plasma Nitriding ◽  
Active Screen

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.

Effect of Pre-Shot Peening on Plasma Nitriding Kinetics of Austenitic Stainless Steel

2013 ◽  
Vol 634-638 ◽  
pp. 2955-2959 ◽  
Author(s):  
Lie Shen ◽  
Liang Wang ◽  
Jiu Jun Xu ◽  
Ying Chun Shan
Keyword(s):  
Stainless Steel ◽  
Surface Layer ◽  
Austenitic Stainless Steel ◽  
Shot Peening ◽  
Plasma Nitriding ◽  
Nitrogen Diffusion ◽  
X Ray Diffraction ◽  
304 Austenitic Stainless Steel ◽  
Strain Induced Martensite ◽  
Kinetics Of

The fine grains and strain-induced martensite were fabricated in the surface layer of AISI 304 austenitic stainless steel by shot peening treatment. The shot peening effects on the microstructure evolution and nitrogen diffusion kinetics in the plasma nitriding process were investigated by optical microscopy and X-ray diffraction. The results indicated that when nitriding treatments carried out at 450°C for times ranging from 0 to 36h, the strain-induced martensite transformed to supersaturated nitrogen solid solution (expanded austenite), and slip bands and grain boundaries induced by shot peening in the surface layer lowered the activation energy for nitrogen diffusion and evidently enhanced the nitriding efficiency of austenitic stainless steel.

Surface Modification of High-Speed Steel by Plasma Nitriding

2014 ◽  
Vol 709 ◽  
pp. 403-409 ◽  
Author(s):  
Bauyrzhan K. Rakhadilov ◽  
Mazhyn Skakov ◽  
Erlan Batyrbekov ◽  
Michael Scheffler
Keyword(s):  
Surface Layer ◽  
Phase Composition ◽  
Diffusion Layer ◽  
High Speed ◽  
Steel Surface ◽  
Plasma Nitriding ◽  
High Speed Steel ◽  
R6m5 Steel ◽  
Modified Layer ◽  
Surface Modified

The article investigates the changing in the structure and phase composition of the R6M5 high-speed steel surface layer after electrolytic-plasma nitriding. It is found that after electrolytic-plasma nitriding on the R6M5 steel surface, modified layer is formed, which consist from a diffusion layer. It was showed phase composition of difysion layer is changing depending on the nitriding. It is found that electrolytic-plasma nitriding lead to accelerated formation of the modified layer. It is determined that after electrolytic-plasma nitriding on the high-speed steel surface, modified layer is formed, consisting only of the diffusion layer.

Wear-Resistance of Nitrided W-Mo-High Speed Steel in Abrasive Wear Conditions

2013 ◽  
Vol 594-595 ◽  
pp. 1117-1121
Author(s):  
Мazhyn Skakov ◽  
Bauyrzhan Rakhadilov ◽  
Merey Rakhadilov
Keyword(s):  
Wear Resistance ◽  
Surface Layer ◽  
Abrasive Wear ◽  
High Speed ◽  
Steel Surface ◽  
Plasma Nitriding ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Abrasive Wear Resistance ◽  
R6m5 Steel

In this work the influence of electrolytic-plasma nitriding on the abrasive wear-resistance of R6M5 high-speed steel were under research. We registered that after electrolytic-plasma nitriding on R6M5 steel surface modified layer is formed with 20-40 μm thickness and with increased microhardness of 9000-12200 MPa. Testing mode for the nitrided samples high-speed steel on abrasive wear developed. It is established, that electrolyte-plasma nitriding allows to increase wear-resistance of R6M5 steel surface layer comparing to original. It was determined that abrasive wear-resistance of R6M5 steel surface layer is increased to 25% as a result of electrolytic plasma nitriding. Thus, studies have demonstrated the feasibility and applicability of electrolytic-plasma nitriding in order to improve cutting tools work resource, working under friction and wear conditions.

The transformation of α-iron to γ-iron during abrasion

1954 ◽  
Vol 223 (1153) ◽  
pp. 167-174 ◽  
Keyword(s):  
Surface Layer ◽  
Electron Diffraction ◽  
Orientation Relationship ◽  
Iron Surface ◽  
Plane Parallel ◽  
Iron Crystal ◽  
Diffraction Patterns

Abrasion of the nearly (110) surface of an iron crystal, by a single 10 in. stroke on 0000 emery with light hand pressure, led to a disorientated α-iron surface layer containing some randomly disposed γ-iron. After etching away this and the neighbouring rotationally disorientated layer of α-iron, a strongly orientated layer of face-centred cubic γ-iron was exposed (with a = 3-60 A), the orientations being independent of the abrasion direction, with a {001} γ plane parallel to a {110} α plane of the α-iron crystal, and a<110> γ row of this face lying parallel to a<110> γ row of this {110} α plane. These γ-lattices were of lamellar form on {111} γ, with {111} twinning. The formation of this y-iron indicates that a rise in temperature of the order of 900° C had been caused at the surface by even this light abrasion. Other electron-diffraction patterns at this stage of etching showed that the α-iron main crystal was exposed in some regions and was bounded by {110} facets, which evidently correspond to the interfaces between the γ- and α-iron. This precisely determined orientation relationship differs from those found by Kurdjumow & Sachs, Nishiyama, and others, and indicates a mechanism of transformation simpler than those hitherto suggested, involving a shear on {211} α along <111> α as in normal {211} twinning.

The Influence of Ti and Zr on the Diffusion of Isotope 63Ni in the Iron Surface Layer at Electric-Spark Alloying in Carbon Containing Environment

2008 ◽  
Vol 277 ◽  
pp. 87-90
Author(s):  
Sergey I. Sidorenko ◽  
E.V. Ivashchenko ◽  
G.G. Lobachova ◽  
V.F. Mazanko
Keyword(s):  
Surface Layer ◽  
Phase Composition ◽  
Anode Material ◽  
Iron Surface ◽  
Alloyed Layer ◽  
Hardness Increase ◽  
Radio Isotopes ◽  
Propane Butane

By the method of radio isotopes (method of depleting) the redistribution of 63Ni was investigated in the surface layer of iron after the Electric-spark alloying by titanium and zirconium in a carbon containing atmosphere and in air. It is proved that the Electric-spark alloying results in diffusive penetration of 63Ni both in the alloyed layer and in material of basis. The depth of isotope’s penetration depends on the nature of an anode material. Alloying by titanium results in penetration of nickel on the depth of 10 μm, that is almost 2 times more than the depth of its penetration if a zirconium anode is used. In particular, a microhardness, microstructure and phase composition of alloyed layers are examined. It is assumed that alloying of iron by zirconium results in the hardness increase. The alloyed layer equals to 10 GPa (at treatment in kerosene) and to 8,6 GPa (at treatment in propane-butane) that exceeds the microhardness values at alloying by titanium.

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