Effect of N2+H2 gas mixtures in plasma nitriding on tribological properties of duplex surface treated steels

Taktak, Sukru; Güneş, İbrahim; Ulker, Sukru; Yalçin, Yılmaz

doi:10.1016/j.matchar.2008.04.010

Cited by 34 publications

(15 citation statements)

References 21 publications

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“…Among various surface modification techniques, thin, hard and wear-resistant metallic nitride coatings, such as TiN, TiCN, TiAlN, ZrN, CrN and Cr 2 N, fabricated by physical vapor deposition (PVD), are commonly used to improve the surface characteristics of steels in some tribological applications under extreme conditions [12][13][14][15]. Also, to enhance the load bearing capacity of the substrate, a diffusion-based surface treatment such as plasma nitriding process that can produce fairly thick surface layers with high load bearing ability is carried out prior to hard coating (duplex surface treatment) [15][16][17][18]. Hence, a smooth hardness transition, which provides better performance, could be obtained.…”

Section: Introductionmentioning

confidence: 99%

The effect of duplex surface treatment on erosion performance of QRO 90 Supreme steel

2019

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In this study, CrN and TiAlN thin films were deposited on plasma-nitrided QRO 90 Supreme hot work tool steel by physical vapor deposition process and analysed with regard to their erosion performance under hydro-abrasive erosion conditions. The as-received specimens were quenched to room temperature from 1050°C and tempered gradually at 605°C for 2 h and at 560°C for 4 h. These specimens were plasma-nitrided for 10 h at 500°C at a pressure of 250 Pa in a gas mixture of 80% N 2 ? 20% H 2 and then coated with TiAlN or CrN coatings by cathode arc evaporation. The specimens were characterized by metallographic techniques, SEM, EDS and micro-hardness test. Plasma nitriding and duplex surface treatments significantly increased the hardness of the specimens and thus significantly reduced the erosion of the specimens. The hardnesses on the surface of plasma-nitrided, CrN-deposited and TiAlN-deposited QRO 90 steels were 1092 HV 0.025 , 2436 HV 0.025 and 3578 HV 0.025 , respectively. TiAlN-coated specimens were about 17-fold harder than the as-received specimens and over 3-fold harder than the plasma-nitrided specimens. The erosion resistance of CrN-coated specimens was increased by a factor of 3.6 and 1.5 compared with that of the as-received and plasma-nitrided specimens, respectively. A brittle fracture phenomenon was observed on the eroded surface of the duplex-treated specimens while a ductile material removal was observed on the as-received and the tempered specimens. The plasma-nitrided specimens showed a mixed behaviour of ductility and brittleness. adhana(0123456789().,-volV)FT3 ](0123456789().,-volV)

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Section: Introductionmentioning

confidence: 99%

The effect of duplex surface treatment on erosion performance of QRO 90 Supreme steel

2019

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“…The nitriding is a surface treatment that can improve wear, corrosion resistance and mechanical behaviour of metallic materials [27][28][29][30][31][32]. In plasma environment, nitrogen is transferred to the metal, and then penetrates into the surface by diffusion which leads to the formation of a modified layer [33].…”

Section: Introduction mentioning

confidence: 99%

Electrochemical and Tribological Behaviour of Ti6Al4V Subjected to the Duplex SMAT/Plasma Nitriding

Jelliti¹,

Retraint²

2018

JPSA

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In this work, SMAT (surface mechanical attrition treatment) was performed on Ti6Al4V. Plasma nitriding of the SMATed samples was investigated in comparison with coarse-grained samples. The samples were characterized using optic microscope, SEM, TEM and Vickers microhardness tester. The results showed that a significantly thicker compound layer with higher hardness was obtained for the SMATed samples when compared with un-SMATed samples after nitriding. Corrosion resistance of Ti6Al4V in a Ringer's solution was studied by electrochemical techniques including open circuit potential measurement, potentiodynamic polarization and EIS (electrochemical impedance spectroscopy). Overall, our results identified the beneficial impacts of the duplex SMAT/nitriding treatment on corrosion behaviour of Ti6Al4V. Wear tests were also performed on a ball-on-disc tribometer where the treated samples were rubbed against a 6 mm diameter alumina ball under a normal load of 5 N using Ringer's solution as lubricant media. The friction coefficient of the SMATed and nitrided samples was reduced compared to the untreated samples. Wear rates demonstrated that SMAT combined with nitriding improved wear resistance of Ti6Al4V alloy.

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“…A typical nitriding process is a plasma‐based technique. Normally, a gas mixture is used for the discharge gas to control the thickness and stoichiometry of the nitrides in the plasma nitriding processes 1–4. Nitrogen radicals such as, excited nitrogen molecules (N 2 *) and nitrogen molecule ions (N 2 + ) can act as reactants in the plasma nitriding processes, and their population changes with the ambient gases in plasmas 5, 6.…”

Section: Introductionmentioning

confidence: 99%

Effect of excitation states of nitrogen on the surface nitridation of iron and steel in d.c. glow discharge plasma

Sato

Hirai

Araki

et al. 2011

Surface & Interface Analysis

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The plasma nitriding phenomena that occur on the surfaces of iron and steel were investigated. In particular, the correlation between the kinds of nitrogen radicals and the surface nitriding reaction was investigated using a glow-discharge apparatus. To control the excitation of nitrogen radicals, noble gas mixtures were used for the plasma gas. The highly populated metastables of noble gases selectively produce excited nitrogen molecules (N 2 * ) or nitrogen molecule ions (N 2 + ). The optical emission spectra suggested that the formation of N 2 * -rich or N 2 + -rich plasma was successfully controlled by introducing different kinds of noble gases. Auger electron spectroscopy and XPS were used to characterize the depth profile of the elements and chemical species on the nitrided surface. The nitride layer formed by a N 2 + -rich plasma had a much higher nitrogen concentration than that by a N 2 * -rich plasma, likely due to the larger chemical activity of the N 2 + species as well as the N 2 + sputtering bombardment to the cathode surface. The strong reactivity of the N 2 + species was also confirmed from the chemical shift of N 1s spectra for iron nitrides. An iron nitride formed by the N 2 + -rich plasma has higher stoichiometric quantity of nitrogen than that formed by the N 2 * -rich plasma. Besides the effect of nitrogen radicals on surface nitridation, the contribution of the chromium in steel to the nitriding reaction was also examined. This chromium can promote a nitriding reaction at the surface, which results in an increase in the nitrogen concentration and the formation of nitride with high nitrogen coordination.

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Effect of N2+H2 gas mixtures in plasma nitriding on tribological properties of duplex surface treated steels

Cited by 34 publications

References 21 publications

The effect of duplex surface treatment on erosion performance of QRO 90 Supreme steel

The effect of duplex surface treatment on erosion performance of QRO 90 Supreme steel

Electrochemical and Tribological Behaviour of Ti6Al4V Subjected to the Duplex SMAT/Plasma Nitriding

Effect of excitation states of nitrogen on the surface nitridation of iron and steel in d.c. glow discharge plasma

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