scholarly journals CHARACTERISTICS OF AISI 420 STAINLESS STEEL MODIFIED BY COMBINING GAS NITRIDING AND CrN COATING

2021 ◽  
Vol 27 (3) ◽  
pp. 146-151
Author(s):  
Thanh Van Nguyen ◽  
Van Thanh Doan ◽  
Trung Van Trinh ◽  
Huy Van Vu
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Load Capacity ◽  
Steel Substrate ◽  
Surface Hardness ◽  
Corrosion Current ◽  
Crn Coating ◽  
Gas Nitriding ◽  
Duplex Coating ◽  
Aisi 420

AISI 420 stainless steel is widely used in applications where wear and corrosion resistance are required. However, the heat treatment and nitriding process can drastically reduce the corrosion resistance of this stainless steel. This article focuses on investigating the influence of steel substrate and gas nitriding efficiency at two temperatures of 520 oC and 550 oC on some properties of CrN coating. The experiments were carried out to evaluate the surface hardness, microstructure and phase composition of nitrided layers. The coating adhesion and load capacity of the coating were performed according to VDI 3198 standard. Electrochemical testing was performed in a solution of 3.5% NaCl and then using the Tafel method to determine the corrosion current and corrosion potential. The thickness of CrN and CrN/CrN coating was 1.6 μm and 3 μm, respectively. The study showed that the corrosion resistance of coatings fabricated through duplex technology was affected not only by the normal defects but also by the porosity on the nitrided surface. The corrosion resistance of multilayer duplex coating was improved compare with mono-layer duplex coating due to its ability to cover and reduce pores and pitting defects.

scholarly journals Effects of nanostructured, diamondlike, carbon coating and nitrocarburizing on the frictional properties and biocompatibility of orthodontic stainless steel wires

2016 ◽  
Vol 86 (5) ◽  
pp. 782-788 ◽  
Author(s):  
Hao Zhang ◽  
Shuyu Guo ◽  
Dongyue Wang ◽  
Tingting Zhou ◽  
Lin Wang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Elastic Modulus ◽  
Corrosion Current Density ◽  
Surface Hardness ◽  
Corrosion Current ◽  
Frictional Properties ◽  
Dlc Coating ◽  
Steel Wires ◽  
Diamondlike Carbon

ABSTRACT Objective:  To evaluate and compare the effects of nanostructured, diamondlike, carbon (DLC) coating and nitrocarburizing on the frictional properties and biocompatibility of orthodontic stainless steel archwires. Materials and Methods:  Plasma-enhanced chemical vapor deposition technology was applied to coat DLC films onto the surface of austenitic stainless steel wires, and salt-bath nitrocarburizing technology was employed to achieve surface hardening of other wires. Surface and cross-sectional characteristics, microhardness, modulus of elasticity, friction resistance, corrosion resistance, and cell toxicity of the modified and control wires were analyzed. Results:  The surfaces of the DLC-coated and nitrocarburized wires were both smooth and even. Compared with the control, the DLC-coated wires were increased in surface hardness 1.46 times, decreased in elastic modulus, reduced in kinetic friction coefficient by 40.71%, and decreased in corrosion current density by two orders of magnitude. The nitrocarburized wire was increased in surface hardness 2.39 times, exhibited an unchanged elastic modulus, demonstrated a decrease in maximum static friction force of 22.2%, and rose in corrosion current density two orders of magnitude. Cytotoxicity tests revealed no significant toxicity associated with the modified wires. Conclusions:  DLC coating and nitrocarburizing significantly improved the surface hardness of the wires, reduced friction, and exhibited good biocompatibility. The nanostructured DLC coating provided excellent corrosion resistance and good elasticity, and while the nitrocarburizing technique substantially improved frictional properties, it reduced the corrosion resistance of the stainless steel wires to a lesser extent.

Study of the Effect of MoS2 and PTFE Based Coatings on Adhesive Wear of Stainless Steel

2013 ◽  
Vol 302 ◽  
pp. 216-222 ◽  
Author(s):  
Thanit Thana ◽  
Karuna Tuchinda
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Adhesion Strength ◽  
Adhesive Wear ◽  
Wear Behavior ◽  
Load Capacity ◽  
Steel Substrate ◽  
Surface Hardness ◽  
Ptfe Film ◽  
The Individual

this paper, the adhesive wear characterization of MoS2, PTFE and mixture of MoS2 and PTFE films coated on stainless steel substrate, i.e. SUS440C, have been studied. The films were deposited by dry spray techniquecommercially available domestically. The films properties which are surface hardness, film thickness, surface roughness and adhesion strength were investigated. The thickness and the surface hardness of the films were approx. 7, 6.8 and 6.2 µm and 0.1,0,8 and 0.4GPa for MoS2, PTFE and the mixture of MoS2 and PTFE, respectively.The surface roughness of MoS2, PTFEwerefound to be similar with the value of Ra of approx. 0.302-0.303 µm. The mixture of MoS2 and PTFE showed smoother surface with the surface roughness (Ra) of approx.0.260µm. The PTFE film has shown better adhesion strength with higher critical load for first failure and full delamination. However, the failure pattern observed suggested lower severity of surface damage.Theresults fromtribologicaltests between the coated SUS440C ball and the SUS304 discshowedstrong effect of the coating on adhesive wear behavior of the contacting systems.For MoS2coated surface, the coatingsurface peeled offgraduallyuntil the surface ofthe substrate was revealed. Whereas, the PTFEcoated surface had delaminated immediately once in contact resulting in plate liked wear debris.The mixture ofMoS2 andPTFE haslower thefriction coefficient compared to the individual coating. Thewearbehavior found on the mixture of MoS2 and PTFE coated surface had similar characteristic to those found on surfacecoatingwithMoS2. It also showed lower wear occurrences with better appearance due to tearing wearat the edges of the worn suggesting better load capacity of the mixed film than the individual PTFE coating.

scholarly journals Laser cladding of Ni60 + 17 − 4PH composite for a cracking-free and corrision resistive coating

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040042
Author(s):  
Zhaohui Chen ◽  
Ruifeng Li ◽  
Jiayang Gu ◽  
Zhongyu Zhang ◽  
Yanwu Tao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Laser Cladding ◽  
Steel Substrate ◽  
Corrosion Current ◽  
Characterization Methods ◽  
Surface Cracking ◽  
Mechanical Properties And Corrosion ◽  
1045 Steel

In order to obtain a laser-cladded coating with no cracking and good corrosion resistance, this paper investigated laser cladding of a mixture of 17-4PH stainless steel and Ni60 powders on ASTM 1045 steel substrate. The surface cracking, mechanical properties and corrosion resistance of the coatings were assessed by various characterization methods. The experimental results demonstrated that a crack-free coating can be obtained by adding 30% (or above) 17-4PH stainless steel into Ni60 alloy. The mechanical properties of the coatings were determined by adding 17-4PH, but stabilized at about 79% of pure Ni60 alloy, which is acceptable considering the benefit of elimination of surface cracking. Decrease in the mechanical properties were caused by the dilution of the strengthening elements and reduction of population of hard phases. Composite coating having 30% of 17-4PH also exhibited the smallest corrosion current, lowest corrosion potential and slowest corrosion rate, and therefore the best corrosion resistance.

UGINOX MA3

Alloy Digest ◽  
2008 ◽  
Vol 57 (7) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Martensitic Stainless Steel ◽  
Heat Treating ◽  
Sharp Edge ◽  
Aisi 420

Abstract Uginox MA3 (X30Cr13, No. 1.4028; AISI 420) is an age-hardenable martensitic stainless steel, mostly used where a sharp edge for cutting is needed. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1015. Producer or source: Arcelor Stainless Processing LLC.

scholarly journals Surface Modification of a Nickel-Free Austenitic Stainless Steel by Low-Temperature Nitriding

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1845
Author(s):  
Francesca Borgioli ◽  
Emanuele Galvanetto ◽  
Tiberio Bacci
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Stainless Steels ◽  
Volume Fraction ◽  
Surface Hardness ◽  
Austenitic Stainless Steels ◽  
Surface Layers ◽  
Modified Surface

Low-temperature nitriding allows to improve surface hardening of austenitic stainless steels, maintaining or even increasing their corrosion resistance. The treatment conditions to be used in order to avoid the precipitation of large amounts of nitrides are strictly related to alloy composition. When nickel is substituted by manganese as an austenite forming element, the production of nitride-free modified surface layers becomes a challenge, since manganese is a nitride forming element while nickel is not. In this study, the effects of nitriding conditions on the characteristics of the modified surface layers obtained on an austenitic stainless steel having a high manganese content and a negligible nickel one, a so-called nickel-free austenitic stainless steel, were investigated. Microstructure, phase composition, surface microhardness, and corrosion behavior in 5% NaCl were evaluated. The obtained results suggest that the precipitation of a large volume fraction of nitrides can be avoided using treatment temperatures lower than those usually employed for nickel-containing austenitic stainless steels. Nitriding at 360 and 380 °C for duration up to 5 h allows to produce modified surface layers, consisting mainly of the so-called expanded austenite or gN, which increase surface hardness in comparison with the untreated steel. Using selected conditions, corrosion resistance can also be significantly improved.

Corrosion Resistance of Nickel-Free Austenitic Stainless Steels and their Nanocomposites with Hydroxyapatite in Ringer's Solution

2011 ◽  
Vol 674 ◽  
pp. 159-163 ◽  
Author(s):  
Maciej Tulinski ◽  
Mieczyslaw Jurczyk
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Mechanical Alloying ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Orthopedic Implants ◽  
Corrosion Current ◽  
Similar Process ◽  
Distinct Advantage ◽  
Ion Release

In this work Ni-free austenitic stainless steels with nanostructure and their nanocomposites were synthesized by mechanical alloying (MA), heat treatment and nitriding of elemental microcrystalline Fe, Cr, Mn and Mo powders with addition of hydroxyapatite (HA). Microhardness and corrosion tests' results of obtained materials are presented. Mechanical alloying and nitriding are very effective technologies to improve the corrosion resistance of stainless steel. Decreasing the corrosion current density is a distinct advantage for prevention of ion release and it leads to better cytocompatibility. Similar process in case of nanocomposites of stainless steel with hydroxyapatite helps achieve even better mechanical properties and corrosion resistance. Hence nanocrystalline nickel-free stainless steels and nickel-free stainless steel/hydroxyapatite nanocomposites could be promising bionanomaterials for use as a hard tissue replacement implants, e.g. orthopedic implants.

scholarly journals Fabrication and Characterization of Zein/Hydroxyapatite Composite Coatings for Biomedical Applications

Surfaces ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 237-250 ◽  
Author(s):  
Yusra Ahmed ◽  
Muhammad Yasir ◽  
Muhammad Atiq Ur Rehman
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Biomedical Applications ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Sem Images ◽  
Taguchi Design Of Experiments ◽  
Hydrophilic Nature ◽  
Strong Adhesion ◽  
Steel Substrates

Stainless steel is renowned for its wide use as a biomaterial, but its relatively high corrosion rate in physiological environments restricts many of its clinical applications. To overcome the corrosion resistance of stainless steel bio-implants in physiological environments and to improve its osseointegration behavior, we have developed a unique zein/hydroxyapatite (HA) composite coating on a stainless steel substrate by Electrophoretic Deposition (EPD). The EPD parameters were optimized using the Taguchi Design of experiments (DoE) approach. The EPD parameters, such as the concentration of bio-ceramic particles in the polymer solution, applied voltage and deposition time were optimized on stainless steel substrates by applying a mixed design orthogonal Taguchi array. The coatings were characterized by using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and wettability studies. SEM images and EDX results indicated that the zein/HA coating was successfully deposited onto the stainless steel substrates. The wettability and roughness studies elucidated the mildly hydrophilic nature of the zein/HA coatings, which confirmed the suitability of the developed coatings for biomedical applications. Zein/HA coatings improved the corrosion resistance of bare 316L stainless steel. Moreover, zein/HA coatings showed strong adhesion with the 316L SS substrate for biomedical applications. Zein/HA developed dense HA crystals upon immersion in simulated body fluid, which confirmed the bone binding ability of the coatings. Thus the zein/HA coatings presented in this study have a strong potential to be considered for orthopedic applications.

Effect of Gas Content and Treatment Temperature on the Characteristic of Surface Layers of Low Temperature Plasma Nitrided 316L Austenitic Stainless Steel

2018 ◽  
Vol 941 ◽  
pp. 1784-1789
Author(s):  
Insup Lee
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Surface Hardness ◽  
Treatment Temperature ◽  
S Phase ◽  
Gas Content ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Phase Layer ◽  
316L Austenitic Stainless Steel

The effect of gas content and treatment temperature on the surface characteristics of hardened layers of low temperature plasma nitrided 316L Austenitic Stainless Steel was investigated. The process was performed at fixed processing time at 15Hr and changing the N2content from 10% to 25%, changing the treatment temperature from 370 °C to 430 °C. The surface hardness and the thickness of expanded austenite (S-Phase) layer increase with increasing both temperature and nitrogen content. At 430°C processing temperature and 25% N2content, the S-phase layer thickness increased up to 13 μm and surface hardness increased about 3.5 times of that of untreated sample which is 880 HV0.1(before treatment 250HV0.1hardness). However, the XRD pattern of the this sample shows the presence of γ'-(Fe,Cr)4N precipitation on the surface which is the reason for the increased corrosion current density that results in increased corrosion rate. Thus the corrosion resistance degrades and presents even worst behavior comparing that of before treatment. Therefore, for increasing the corrosion behavior, further research was conducted by fixing the N2content at 10% with changing the CH4content from 0% to 5%. The best results were found when treated at 430°C with 5% CH4content. At this condition the S-phase thickness increase to around 17μm and surface hardness (980 HV0.1) is improved about 3.9 times of the hardness of untreated one. This sample also showed superior corrosion resistance than the other treated samples and the untreated one due to much higher pitting potential.

Nitriding and carbonitriding of stainless steel X20Cr13 in fluidized bed

2018 ◽  
Vol 23 (2) ◽  
pp. 52-64
Author(s):  
Tadeusz Żółciak ◽  
Jerzy Jastrzębski
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Fluidized Bed ◽  
Pitting Corrosion ◽  
Surface Hardness ◽  
Process Conditions ◽  
Surface Activation ◽  
Pitting Corrosion Resistance

Current study investigated influence of process conditions upon structure and case growth during nitriding/carbonitriding steel X20Cr13 in fluidized bed and also resistance of those cases against pitting corrosion. Short surface activation in ammonia or in ammonia with propane made possible difusion N, C into steel X20Cr13. Activation in ammonia with propane promotes creation the so called “white case” during carbonitriding at 570oC. After nitriding/carbonitriding at 570oC/4 h case thickness of 150 μm and compounds zone – 15 μm were achieved. Nitriding/carbonitriding at lower temperatures 480oC and 440oC gave cases without compounds zones. After nitriding or carbonitriding at 440oC/6 h surface hardness was 1320 and 1370 HV1 respectively. Increase of pitting corrosion resistance was obtained after nitriding/carbonitriding 570oC/2 h with initially surface activation in ammonia by 2 h. Phase investigations of such samples shown that compounds zone consist of: Fe3N, Fe4N, M7C3, CrN, Fe3O4, Fe2O3.

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