scholarly journals Low-Temperature Plasma Nitriding of 3Cr13 Steel Accelerated by Rare-Earth Block

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1050
Author(s):  
Yuan You ◽  
Rui Li ◽  
Mufu Yan ◽  
Jihong Yan ◽  
Hongtao Chen ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Mass Gain ◽  
Corrosion Current ◽  
Maximum Increase ◽  
Temperature Plasma ◽  
Pitting Potential ◽  
Modified Layer

The plasma nitriding of 3Cr13 steel occurred at 450 °C for 4, 8 and 12 h in NH3 with and without rare earth (RE). The nitrided layers were characterized using an OM, SEM, TEM, XRD, XPS, microhardness tester and electrochemical workstation. The modified layer, with and without La, are composed of a compound layer and diffusion layer from surface to core. After the addition of La during nitriding, the maximum increase of layer thickness, mass gain and average microhardness was 15.6%, 35.8% and 212.50HV0.05, respectively. With the increase of the proportion of ε-Fe2-3N, the passivation zone of the corrosion resistance curve increases from 2.436 to 3.969 V, the corrosion current density decreases, the corrosion potential and pitting potential both increase, and, consequently, the corrosion resistance is significantly improved. Most of the surface microstructures of the nitrided layer was refined by the addition of La. The presence of La reduces the N content in the modified layer, which accelerates the diffusion of N atoms and, thus, accelerates the nitriding process.

scholarly journals Acceleration of Plasma Nitriding at 550 °C with Rare Earth on the Surface of 38CrMoAl Steel

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1122
Author(s):  
Dongjing Liu ◽  
Yuan You ◽  
Mufu Yan ◽  
Hongtao Chen ◽  
Rui Li ◽  
...  
Keyword(s):  
Rare Earth ◽  
Electron Microscope ◽  
Weight Gain ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Optical Microscope ◽  
Steel Microstructure ◽  
Transmission Electron ◽  
Modified Layer

In order to explore the effect of the addition of rare earth (RE) to a steel microstructure and the consequent performance of a nitrided layer, plasma nitriding was carried out on 38CrMoAl steel in an atmosphere of NH3 at 550 °C for 4, 8, and 12 h. The modified layers were characterized using an optical microscope (OM), a microhardness tester, X-ray diffraction (XRD), a scanning electron microscope (SEM), a transmission electron microscope (TEM), and an electrochemical workstation. After 12 h of nitriding without RE, the modified layer thickness was 355.90 μm, the weight gain was 3.75 mg/cm2, and the surface hardness was 882.5 HV0.05. After 12 h of RE nitriding, the thickness of the modified layer was 390.8 μm, the weight gain was 3.87 mg/cm2, and the surface hardness was 1027 HV0.05. Compared with nitriding without RE, the ε-Fe2-3N diffraction peak was enhanced in the RE nitriding layer. After 12 h of RE nitriding, La, LaFeO3, and a trace amount of Fe2O3 appeared. The corrosion rate of the modified layer was at its lowest (15.089 × 10−2 mm/a), as was the current density (1.282 × 10−5 A/cm2); therefore, the corrosion resistance improved.

scholarly journals Effects of Surface Modification by Means of Low-Temperature Plasma Nitriding on Wetting and Corrosion Behavior of Austenitic Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 98 ◽  
Author(s):  
Francesca Borgioli ◽  
Emanuele Galvanetto ◽  
Tiberio Bacci
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Surface Morphology ◽  
Corrosion Behavior ◽  
Sessile Drop ◽  
Plasma Nitriding ◽  
Surface Hardness ◽  
Temperature Plasma

Low-temperature nitriding of austenitic stainless steels produces modified surface layers, consisting mainly of the S phase, which improve surface hardness and corrosion resistance. Because of the localized plastic deformations, owing to modified layer formation, and ion bombardment occurring during the process itself, this treatment produces also modifications of surface morphology and roughness, which can affect wettability and corrosion behavior. In this study the effects of plasma nitriding, performed using different treatment conditions, on the surface morphology and roughness, and thus on wettability and corrosion resistance, of AISI 202 specimens with different initial finishings (2D and polished finishing) were investigated. Different probe liquids, having both high (bi-distilled water and solution of 3.5% NaCl) and low (ethanol and rapeseed oil) surface tension, were employed for assessing the wetting behavior with the sessile drop method. The contact angle values for water increased markedly when nitriding was performed on polished samples, while this increase was smaller for 2D samples, and on selected specimens a hydrophobic behavior was observed. Very low contact angle values were registered using low surface tension liquids, suggesting an oleophilic behavior. Corrosion resistance in a 5% NaCl solution was assessed, and it depended on the characteristics of the nitrided specimens.

Corrosion Resistance of Rare Earth Modified Chromizing Coating on P110 Oil Casing Tube Steel by Pack Cementation

2009 ◽  
Vol 79-82 ◽  
pp. 1075-1078
Author(s):  
Nai Ming Lin ◽  
Fa Qin Xie ◽  
Tao Zhong ◽  
Xiang Qing Wu ◽  
Wei Tian
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Steel Substrate ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Pack Cementation ◽  
Tube Steel ◽  
X Ray ◽  
Immersion Corrosion ◽  
P110 Steel

The rare earth (RE) modified chromizing coating was obtained on P110 oil casing tube steel (P110 steel) substrate by means of pack cementation technique to enhance the resistance against corrosion of P110 steel. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) were employed to research microstructure, composition distribution and phase constitution of the chromizing coating. The effect of minor addition of RE on the microstructure of chromizing was discussed. Corrosion resistance of chromizing coating was investigated and compared with that of bare P110 steel via electrochemical corrosion and immersion corrosion in simulated oilfield brine solution, respectively. The results showed that a uniform, continuous and compact coating was formed on P110 steel. The coating with RE addition was more compact than that of the coating added no RE, and a small amount of RE addition could promote the chromizing procedure notably. From SEM and EDX investigation, it had been confirmed that the coating was composed of two different layers, an out layer and an inner layer; the coating mainly contains Fe and Cr; the concentration of Cr decreased as the distance from the surface increased, yet Fe presented the inverse trend. XRD analysis indicated the coating was built up by (Cr, Fe)23C6 referring to the out layer, (Cr, Fe)7C3, Cr7C3 and α-(Cr, Fe) corresponding to the inner layer. Electrochemical corrosion consequence was obtained as follows: the self-corroding electric potential of chromizing coating was higher, and the corrosion current density was lower than that of bare P110 steel, which revealed that chromizing coating had better anti-corrosion performance; immersion corrosion results demonstrated the mass loss of chromized P110 steel was lower, and this meant that chromizing coating had a better corrosion resistance than that of bare P110 steel on the experimental condition. A compact (Cr, Fe)xCy coating can be fabricated by pack cementation technique. As a result of minor RE addition, microstructure and corrosion resistance of the chromizing coating are improved obviously.

Low Temperature Fluidized Bed Nitriding of Austenitic Stainless Steel

2006 ◽  
Vol 118 ◽  
pp. 125-130 ◽  
Author(s):  
E. Haruman ◽  
Y. Sun ◽  
H. Malik ◽  
Agus Geter E. Sutjipto ◽  
S. Mridha ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Fluidized Bed ◽  
Corrosion Behaviour ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Temperature Plasma ◽  
316L Austenitic Stainless Steel ◽  
Fluidized Bed Process

In the present investigation, low temperature nitriding has been attempted on AISI 316L austenitic stainless steel by using a laboratory fluidized bed furnace. The nitriding was performed in temperature range between 400°C and 500°C. X-ray diffraction, metallography, and corrosion tests were used to characterize the resultant nitrided surface and layers. The results showed that fluidized bed process can be used to produce a precipitation-free nitrided layer characterized by the S phase or expanded austenite on austenitic stainless steel at temperatures below 500°C. But there exists a critical temperature and an incubation time for effective nitriding, below which nitriding is ineffective. The corrosion behaviour of the as-nitrided surfaces is significantly different from that previously reported for low temperature plasma nitriding. This anomaly is explained by the formation of iron oxide products and surface contamination during the fluidized process.

Corrosion Behavior of Active-Screen Plasma Nitrided 17-4 PH (H1150D) Steel in H2S/CO2-Containing Environments

CORROSION ◽  
10.5006/3273 ◽  
2019 ◽  
Vol 75 (10) ◽  
pp. 1237-1245
Author(s):  
Mario Sergio Della Roverys Coseglio ◽  
Xiaoying Li ◽  
Hanshan Dong ◽  
Brian J. Connolly ◽  
Phil Dent ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Produced Water ◽  
Plasma Nitriding ◽  
Outer Part ◽  
High Strength Steels ◽  
Compound Layer ◽  
Localized Corrosion ◽  
Sem Micrographs ◽  
Modified Layer

The presence of hydrogen sulfide (H2S) in typical oilfield environments promotes hydrogen absorption and subsequent failure of high-strength steels by sulfide stress cracking (SSC). Plasma nitriding is as a potential method to increase the resistance of the 17-4 PH to SSC, although further investigation is required to evaluate the corrosion resistance of the modified layer when it is exposed to H2S-containing environments. The aim of this study was therefore to evaluate the corrosion resistance of the 17-4 PH in typical oilfield environment. Samples were plasma nitrided at low (420°C) and high (500°C) temperatures and immersed in produced water with mixed H2S and CO2. The electrochemical data and scanning electron microscopy (SEM) micrographs showed that there were no detrimental effects on the corrosion resistance when plasma nitriding was performed at low temperature (420°C), whereas the integrity of the modified layer was compromised when an elevated temperature (500°C) was applied. The enhanced resistance to localized corrosion of the nitride case obtained after the low-temperature surface modification was attributed to the formation of a compound layer of mixed M4N/M2-3N, the inner section being more corrosion resistant than the outer part, as revealed by SEM micrographs.

Tribological Properties and Corrosion Resistance Properties of NbN/TiN Multilayer, TiNb-NX Single-Layer and Coatings that are Doped with Carbon

2021 ◽  
Vol 901 ◽  
pp. 208-218
Author(s):  
Kun Lin Kuo ◽  
Yen Liang Su ◽  
Wen Hsien Kao ◽  
Yin Hsiang Mao ◽  
Tang Wei Liang
Keyword(s):  
Corrosion Resistance ◽  
Wear Rate ◽  
Tribological Properties ◽  
Solid Lubricant ◽  
Single Layer ◽  
Rf Magnetron Sputtering ◽  
Corrosion Current ◽  
Multilayer Coatings ◽  
Pitting Potential ◽  
Aisi 52100

NbN/TiN, TiNb-NX and CH-TiNb-N12 coatings are deposited by RF magnetron sputtering to determine the tribological properties and corrosion resistance. ‘x’ is the flux rate for nitrogen and ‘CH’ signifies the addition of acetylene. In terms of the corrosion resistance, all the coatings have a similar corrosion potential and NbN/TiN multilayer coatings exhibit the lowest corrosion current. The NbN/TiN multilayer has a low pitting potential so severe pitting corrosion is observed on the surface. CH-TiNb-N12 coating is most resistant to corrosion and exhibits no pitting before the test ends. In contact with counter-bodies with a Si3N4 ball or an AISI 52100 ball, a CH-TiNb-N12 coating acts as a solid lubricant so the wear mechanism shows the least abrasion. The CH-TiNb-N12 coating has the lowest wear rate and coefficient of friction for sliding against Si3N4 and AISI 52100 balls. The wear rate is respectively 3.2 and 6.8 times less than that for SKH51 substrate when sliding against Si3N4 and AISI 52100 balls. The results for this study show that a TiNb-N12-CH coating has the best tribological properties and corrosion resistance.

scholarly journals Use of plasma nitriding to improve the wear and corrosion resistance of 18Ni-300 maraging steel manufactured by selective laser melting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Godec ◽  
B. Podgornik ◽  
A. Kocijan ◽  
Č. Donik ◽  
D. A. Skobir Balantič
Keyword(s):  
Corrosion Resistance ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Solution Treatment ◽  
Thermochemical Treatment ◽  
Laser Melting ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance

Abstract18Ni-300 maraging steel manufactured by selective laser melting was plasma nitrided to improve its wear and corrosion resistance. The effects of a prior solution treatment, aging and the combination of both on the microstructure and the properties after nitriding were investigated. The results were compared with conventionally produced 18Ni-300 counterparts subjected to the same heat- and thermo-chemical treatments. The plasma nitriding was performed under the same conditions (temperature of 520 °C and time of 6 h) as the aging in order to investigate whether the nitriding and the aging could be carried out simultaneously in a single step. The aim of this work was to provide a better understanding of the morphology and chemical composition of the nitrided layer in the additive-manufactured maraging steel as a function of the prior heat treatments and to compare the wear and corrosion resistance with those of conventional maraging steel. The results show that nitriding without any prior aging leads to cracks in the compound layer, while nitriding of the prior-heat-treated additive-manufactured maraging steel leads to benefits from the thermochemical treatment in terms of wear and corrosion resistance. Some explanations for the origins of the cracks and pores in the nitride layers are provided.

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