scholarly journals Investigation of formation of hardened layer on titanium alloys by the method of ion-plasma nitriding

2019 ◽  
Vol 64 (1) ◽  
pp. 25-34
Author(s):  
I. L. Pobol ◽  
I. G. Oleshuk ◽  
A. N. Drobov ◽  
Sun Feng ◽  
Wang Lin
Keyword(s):  
Corrosion Resistance ◽  
Friction Coefficient ◽  
Titanium Alloys ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Saturation Pressure ◽  
Hardened Layer ◽  
Technological Parameters ◽  
Ion Plasma ◽  
Increase Wear Resistance

 Various methods are applied in the world practice to increase wear resistance, fatigue strength and corrosion resistance of aviation equipment, machinery and medicine parts made of titanium and its alloys. Ion-plasma nitriding provides the ultimate effect making it possible to obtain hardened layers with hardness of HV0.01 650–1000 with a thickness of 0.07–0.20 mm for 3–6 hours, depending on the grade of the titanium alloy.Technological factors effecting on the efficiency of ion-plasma nitriding of materials are the process temperature, duration of saturation, pressure, composition and flow rate of the working gas mixture. The effect of these technological parameters on the microstructure, microhardness and depth of hardened layers is investigated in the work. It is shown that hardness and depth of the nitrided layer can be controlled by changing the composition, volume and periodicity of the gaseous medium (nitrogen and argon) supply at the stages of heating and holding time of the samples from titanium and its alloys under ion-plasma nitriding. The tribological characteristics of titanium alloys as-received and the same ones subjected to ion-plasma nitriding under friction conditions without a lubricant were studied. For VT1-0 and VT6 alloys in the as-received state during the tests there is a monotonous decrease of the friction coefficient from 0.35–0.40 to 0.25, after nitriding the friction coefficient monotonically increases from 0.14 up to 0.30 when removing the hardened layer.Studies of corrosion resistance of titanium VT1-0, carried out in a 10 % solution of sulfuric acid, showed that after ion-plasma nitriding at a temperature of 830 °C for 6 hours, the corrosion resistance increases, as the positive polarization potential of the sample shows.

Pulsed plasma nitriding of high velocity oxy-fuel sprayed Inconel 625 coatings

2021 ◽  
pp. 135065012110625
Author(s):  
Harun Mindivan
Keyword(s):  
Corrosion Resistance ◽  
Friction Coefficient ◽  
High Velocity ◽  
Constant Pressure ◽  
Plasma Nitriding ◽  
Inconel 625 ◽  
Pulsed Plasma ◽  
Nacl Solution ◽  
Excellent Corrosion Resistance ◽  
Gas Ratio

A hardening of high velocity oxy-fuel sprayed Inconel 625 coating systems was performed by pulsed plasma nitriding treatment. After deposition of an Inconel 625 coating, samples were pulsed plasma nitrided at 520 °C for 12 h in a gas ratio of 3:1 N2 and H2 under a constant pressure of 2.5 × 102 Pa. Pulsed plasma nitriding improved the microhardness of the high velocity oxy-fuel sprayed Inconel 625 coating from 355 to 401 HV0.05. The high velocity oxy-fuel-sprayed Inconel 625 coating after pulsed plasma nitriding process showed excellent corrosion resistance as well as a reduction of both the friction coefficient and wear rate during the sliding phase in a 3.5 wt.% NaCl solution against sliding action of Al2O3 ball.

Fretting Fatigue Studies of Surface Modified Biomedical Titanium Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 681-686
Author(s):  
Aravind Vadiraj ◽  
M. Kamaraj
Keyword(s):  
Friction Coefficient ◽  
Titanium Alloys ◽  
Thermal Oxidation ◽  
Fatigue Damage ◽  
Plasma Nitriding ◽  
Normal Pressure ◽  
Fretting Fatigue ◽  
Laser Nitriding ◽  
Surface Modified

Fretting fatigue is a form of adhesive wear damage caused due to tangential micro motion of two contact bodies under normal pressure and cyclic load. Biomedical implants such as hip joints and bone plates undergo fretting fatigue damage leading to premature in-vivo failure and revision surgeries. Surface modification of implants delays the process of fretting and thereby improves the life of these medical devices. This work involves investigation of fretting fatigue damage of surface treated titanium alloys couple. The surface treatment involves PVD TiN coating, Plasma nitriding, Ion Implantation, Laser nitriding and thermal oxidation. Fretting of all surface treated alloys have shown both adhesive and abrasive mode of contact damage. Friction coefficient of all the surface treated pairs is less compared to uncoated alloys. Plasma nitrided pairs have shown the best performance in terms of fretting fatigue life and friction coefficient compared to all other coatings. Ion implanted pairs have shown little improvement in fretting fatigue lives due to shallow modified layer. PVD TiN coated pairs have irregular friction pattern due to abrasive particles at contact. Thermal oxidation and Laser nitriding have shown poor fretting fatigue performance due to high case thickness.

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.

scholarly journals HARDNESS OF NITRIDED LAYERS TREATED BY PLASMA NITRIDING

2020 ◽  
Vol 27 ◽  
pp. 53-56
Author(s):  
Zdeněk Joska ◽  
Zdeněk Pokorný ◽  
Jaromír Kadlec ◽  
Zbyněk Studený ◽  
Emil Svoboda
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Austenitic Stainless Steels ◽  
Aisi 316L ◽  
Aisi 304 ◽  
Measurement Surface

Stainless steels, particularly the austenitic stainless grades are widely used in many industries due to good corrosion resistance, but very poor mechanical properties as surface hardness and wear resistance limit its possible use. Plasma nitriding is one of the few ways to increase the surface hardness of these steels, even though this will affect its corrosion resistance. This paper focuses on the description of the mechanical properties of nitrided layers in the two most widespread austenitic stainless steels AISI 304 and AISI 316L. The microstructure and properties of nitrided layers were evaluated by metallography and microhardness measurement. Surface properties of nitrided steels were characterized by Martens hardness. The results show that plasma nitriding created very hard nitrided layers with thickness about 40 μm and microhardness about 1300 HV0.05. Surface hardness measurements have shown that the maximum values for both steels are about 8.5 GPa, but have different behaviour under higher loads, when the AISI 316L nitrided layer began to crack on the surface and sink.

The Characteristics of Surface Layers Produced on SKD 61 Steel by Plasma Radical Nitriding Compared with Conventional Plasma Ion Nitriding

2006 ◽  
Vol 118 ◽  
pp. 155-160
Author(s):  
Insup Lee ◽  
Yong Ho Park ◽  
Ik Min Park
Keyword(s):  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Compound Layer ◽  
Hardened Layer ◽  
Processing Parameters ◽  
Polished Surface ◽  
Nitrogen Diffusion ◽  
Ion Nitriding ◽  
Surface Layers

Plasma radical nitriding has been performed to harden the surface of SKD 61 steel for 1- 10 hours at temperature range of 450-550°C. A NH radical, which has played a key role to produce a nitrogen diffusion layer without the formation of the brittle compound layer, has been generated in a gas mixture of NH3 and H2 . One of the main advantages of the plasma radical nitriding is to improve the surface hardness by maintaining the roughness of the initial polished surface. The microstructures and material properties of the radical nitrided layer have been characterized in order to investigate the effects of various radical nitriding processing parameters. The hardness and surface roughness of the hardened layer were compared between two processes. In addition, PVD CrN coating has been deposited on both the radical nitrided substrates and conventional nitrided substrates by an arc ion plating (AIP) technique. The effect of two different of plasma nitriding treatments on the adhesive strength of the coating layer on the substrates was also investigated.

Surface Modification of SS2205 Duplex Stainless Steel by Plasma Nitriding at Anodic Potential

2014 ◽  
Vol 881-883 ◽  
pp. 1263-1267 ◽  
Author(s):  
Shuo Zhao ◽  
Liang Wang ◽  
Jiu Jun Xu ◽  
Y. Shan
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Surface Hardness ◽  
Anodic Potential ◽  
Wear And Corrosion

The duplex stainless steel has better pitting corrosion resistance but lacks of hardness and wear resistance. Therefore, the low temperature nitriding treatment can be used to increase its hardness and wear resistance or to gain more perfect corrosion resistance. The plasma nitriding of SS2205 stainless steel was carried out at temperatures from 693k to 753k for 4 hours at anodic potential. The nitrided samples were analyzed by optical microscopy, X-ray diffraction, SEM-EDX analysis, microhardness testing, wear and corrosion evaluation. The XRD analysis of all treated samples showed that the nitrogen-expanded austenite phase was formed. Both α and γ phase of the substrate were transformed into γNduring plasma nitriding. Observing the nitrided layers formed on α and γ phase, the ones situated in the austenite were thinner than the ones in the ferrite. This phenomenon was more evident at low temperature, which confirmed that the nitrogen has a higher diffusion rate in the ferrite during plasma nitriding treatment. The surface hardness of nitrided layer was increased with the nitriding temperature. The highest hardness value obtained in this experiment was about 1300 HV0.05which was 4 times as the original sample (380 HV0.05). Furthermore, through the wear and corrosion property tests, it was shown that anodic plasma nitriding improved the wear resistance and corrosion resistance of the duplex stainless steel.

scholarly journals INFLUENCE OF SURFACE PRE-HEATING ON THE NITRIDING DEPTH OF STEEL 25CrMoVA USED COMPLEX ION-PLASMA TREATMENT

2021 ◽  
pp. 115-121
Author(s):  
V.A. Belous ◽  
Yu.A. Zadneprovskiy ◽  
I.S. Domnich
Keyword(s):  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Heated Surface ◽  
Spectral Energy ◽  
Thermal Heating ◽  
Additional Increase ◽  
Preliminary Heating ◽  
Ion Plasma ◽  
Energy Dispersive Microanalysis ◽  
Complex Ion

In the method of nitriding elements, various methods of their thermal heating are used. The simplest heating method in ion-plasma nitriding is heating by bombarding the surface first with low-energy gas ions and then with metal ions with energies up to several kiloelectronvolt. Elements exposed to ion bombardment have a welldeveloped surface that is free from contaminants and facilitates the diffusion of nitrogen into the depth of the metal during nitriding. The paper studies the effect of various preliminary heating methods on the nitriding depth in the complex ion-plasma hardening technology of 25CrMoVA steel. A JSM 7000-1F scanning electron microscope equipped with an X-ray spectral energy dispersive microanalysis attachment was used to diagnose changes occurring on the surface of the samples and at depth; the hardness was measured using a Nanoindentor G200 device. The preliminary heating of the samples was carried out both with the use of bombardment with Ti or Mo ions, and without its direct effect on the heated surface. In the experiment, differences in the depth of hardening of the nitrided layer of steel are observed when it is heated in different ways. When bombarded with Mo ions, the greatest depths of hardening were obtained in comparison with other preliminary heating conditions. It is shown that these differences are associated with the features of the morphology of the steel surface formed as a result of sputtering processes. The formation of nitride compounds in its surface layer can serve as a barrier that slows down the penetration of nitrogen into the metal. It is shown that with complex treatment in the process of deposition of a nitride coating on the surface of nitrided steel, an additional increase in the depth of hardening of the nitrided layer occurs.

scholarly journals Possibilities of Additive Technologies for the Manufacturing of Tooling from Corrosion-Resistant Steels in Order to Protect Parts Surfaces from Thermochemical Treatment

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1551
Author(s):  
Alexander Metel ◽  
Tatiana Tarasova ◽  
Evgenii Gutsaliuk ◽  
Roman Khmyrov ◽  
Sergei Egorov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Linear Thermal Expansion ◽  
Thermochemical Treatment ◽  
Spheroidal Graphite ◽  
Corrosion Resistant ◽  
Ion Plasma ◽  
Composition And Structure ◽  
Stage 1

The structure and physical–mechanical properties of products made from powders of corrosion-resistant steel 12X18H10T by the laser-beam powder bed fusion (LB-PBF) and subsequent ion-plasma nitriding in the work were investigated. Comparative studies of the physical mechanical properties of specimens made by the LB-PBF and conventional method from steel of the same grade were carried out. The density of the specimens and the coefficient of linear thermal expansion (CLTE) after the LB-PBF are almost the same as those of the conventionally manufactured specimens. Our analysis of the obtained dilatograms in the temperature range from 20 to 600 °C showed that the CLTE of steel after the LB-PBF is within acceptable limits (18.6 × 10−6 1/°C). Their hardness, tensile strength, yield strength and elongation are higher than those of a conventionally manufactured specimen. The phase composition and structure of specimens of steel 12X18H10T made by the LB-PBF after the process of ion-plasma nitriding were investigated. The obtained results show that the mode of ion-plasma nitriding used in this case (stage 1—570 °C for 36 h; stage 2—540 °C for 12 h) does not lead to deterioration of the characteristics of the selected steel. A technological process for the manufacture of modified tooling from 12X18H10T steel by the LB-PBF was developed. It protects the surfaces that are not subject to nitriding and makes it possible to obtain a uniform high-quality nitrided layer on the working surface of the part made from spheroidal graphite iron.

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.

Use of Plasma Nitriding to Improve the Wear and Corrosion Resistance of 18Ni-300 Maraging Steel Manufactured by Selective Laser Melting

2020 ◽  
Author(s):  
Matjaž Godec ◽  
Bojan Podgornik ◽  
Aleksandra Kocijan ◽  
Črtomir Donik ◽  
Danijela 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

Abstract 18Ni-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 hours) 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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