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Abstract

Purpose

Aims to investigate the effect of chlorine on corrosion behaviours of stainless steels.

Design/methodology/approach

Very complicated thermodynamic calculations are needed to establish the E‐pH diagrams of commercial alloys, because they comprise of many elements. To avoid these complex calculations and facilitate corrosion prevention of AISI 316L stainless steel, the potentiodynamic method was used to construct the E‐pH diagram. The polarization curves were carefully experimented at the scan rate of 0.1 mV/s. The experimental conditions were aqueous solutions saturated with air (oxygen concentration 7.8‐8.5 ppm) containing chloride 0, 50, 500 and 5,000 ppm, pH 2, 4, 6, 8, 10 and 12, and at 25°C. The transpassive or pitting potential, the protection potential, the primary passive potential and the corrosion potential were determined from the polarization curves and plotted with respect to the pH of the solution. The ions in solution were investigated by qualitative chemical analysis and stated in the E‐pH diagrams.

Findings

The constructed E‐pH diagrams showed clearly the effect of chloride concentration in the tested conditions on the transpassive or pitting potential, the protection potential of AISI 316L stainless steels. The ion states after pitting corrosion were different at low and high pH. This may be useful information for further investigation of pitting corrosion mechanisms.

Research limitations/implications

The E‐pH diagram was originally based on thermodynamic equilibrium. The potentiodynamic method was kinetically controlled and not in equilibrium. However, the experiments were kept at near stationary state as much as possible. The investigated E‐pH diagrams were limited for the solutions saturated with air containing chloride 0, 50, 500 and 5,000 ppm and at 25°C. The effects of temperature and other ions such as Fe3+, Mg2+, Ca2+, etc. on the transpassive or pitting potential, the protection potential, the primary passive potential and the corrosion potential should be further investigated, because natural water may contain those ions and is at high temperatures which could affect on the corrosion of AISI 316L stainless steels.

Practical implications

The investigated E‐pH diagrams may be applicable to avoid corrosion of AISI 316L stainless steels in similar conditions. The useful application may be for fields where natural water is not able to be treated, as is carried out in industry.

Originality/value

There have been several investigations on the effect of chloride on the corrosion behaviours of AISI 316L stainless steels. However, those investigations were carried out in different conditions. Very few experimental E‐pH diagrams of AISI 304L have been found, but not for AISI 316L stainless steels. The investigated diagrams showed also the ion states in pitting corrosion region which were influenced by pH. This may indicate the different pitting corrosion mechanism at different pH.

Details

Anti-Corrosion Methods and Materials, vol. 53 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 22 March 2013

V. Muthukumaran, M. Senthil kumar and V. Selladurai

The purpose of the paper is to study effect of the implantation of oxygen and helium ions on the corrosion performance of the AISI3l6L stainless steel. It presents useful…

Abstract

Purpose

The purpose of the paper is to study effect of the implantation of oxygen and helium ions on the corrosion performance of the AISI3l6L stainless steel. It presents useful new results which allows one to draw conclusions as to the suitability of the helium and oxygen ion implanted AISI 316L stainless steel for biomedical use in the body.

Design/methodology/approach

The implantation of oxygen and helium ions was done on AISI 316L SS at an energy level of 100 keV at a dose of 1×1017 ions/cm2, at room temperature. In order to simulate the natural tissue environment, an electrochemical test using cyclic polarization was done in a 0.9 percent sodium chloride solution at a pH value of 6.3 at 37°C. This was carried out on both the virgin and implanted AISI 316L stainless steel for the purpose of comparing performance. In addition to this, the hardness of the virgin and implanted samples was also studied using Vickers microhardness tester with varying loads. Besides, the surface morphologies of the implanted samples and the corroded samples were studied with XRD and SEM.

Findings

From the study the following findings are made. First, the XRD and SEM results were found to be in accordance with the corrosion test results. Second, the general corrosion behavior showed a significant improvement in the case of both helium implanted (icorr=0.0689 mA/cm2) and oxygen implanted (icorr=1.104 mA/cm2), when compared to the virgin AISI 316L SS (icorr=1.2187 mA/cm2). The pitting corrosion showed a significant improvement for helium implanted (Epit=230 mV) when compared to virgin material (Epit=92 mV). The oxygen implanted has not shown any improvement (Epit=92 mV). The surface hardness is found to be 1202 HV for helium implanted and 1020 HV for oxygen implanted, while it is found to be 195 HV for the virgin material. The hardness of the helium and oxygen implanted samples is found to be increased by about 600 percent and 500 percent, respectively, when compared to the virgin samples. Helium implanted samples show better performance in terms of corrosion resistance and hardness when compared to those of the oxygen implanted samples.

Originality/value

Although a number of authors have conducted many research on AISI 316L stainless steel, this work has original experimental results in terms of the oxygen and helium ion implantation parameters used and the specific tests: microhardness, electrochemical corrosion test, SEM and XRD that were used. It thus presents useful new results which allows one to draw conclusions as to the suitability of the Helium and Oxygen ion implanted AISI 316L stainless steel for biomedical use.

Details

Journal of Engineering, Design and Technology, vol. 11 no. 1
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 12 November 2018

Wen-Hsien Kao and Yean-Liang Su

This paper aims to investigate the effects of plasma nitriding and Ti-C:H coating deposition on AISI 316L and to find the best tribological performance of various specimens.

Abstract

Purpose

This paper aims to investigate the effects of plasma nitriding and Ti-C:H coating deposition on AISI 316L and to find the best tribological performance of various specimens.

Design/methodology/approach

An experimental investigation is performed into the effects of plasma nitriding and Ti-C:H sputtering on the tribological properties of AISI 316L biomedical stainless steel. Five samples are prepared, namely, original AISI 316L stainless steel (code: 316L), nitrided 316L (code: N316), 316L and N316 sputtered with Ti-C:H (codes: D316 and DN316, respectively) and polished N316 sputtered with Ti-C:H (DN316s). The microstructure, mechanical properties and coating adhesion strength of the various samples are investigated and compared. The tribological properties of the samples are then evaluated by means of reciprocating wear tests performed in 8.9 Wt.% NaCl solution against three different counterbodies, namely, a 316L ball, Ti6Al4V ball and Si3N4 ball.

Findings

It is shown that plasma nitriding followed by Ti-C:H deposition (DN316s) improves the tribological properties of AISI 316L; the sample provides the best tribological performance of the various specimens and has a wear rate approximately 156 times lower than that of the original 316L substrate.

Originality/value

The results suggest that nitriding followed by polishing and Ti-C:H sputtering provides an effective means of improving the service life of AISI 316L biomedical implants.

Details

Industrial Lubrication and Tribology, vol. 70 no. 8
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 December 2004

Halit Dogan, Fehim Findik and Ahmet Oztarhan

The tribological properties such as surface hardness, friction and wear have been studied for AISI 316L stainless steel substrates which were co‐ion implanted with…

Abstract

The tribological properties such as surface hardness, friction and wear have been studied for AISI 316L stainless steel substrates which were co‐ion implanted with zirconium and oxygen ions. It is found that the wear resistance for AISI 316L stainless steel substrates implanted with zirconium and oxygen ions increased quite a lot. It is concluded that the increase in surface microhardness and the decrease in friction coefficient of AISI 316L stainless steel substrates play an important role in improving the wear resistance, and the relationship between relative wear volume and microhardness is correlated for zirconium and oxygen co‐ion implantation.

Details

Industrial Lubrication and Tribology, vol. 56 no. 6
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 June 1997

Inder Singh, A.K. Bhattamishra and D.K. Basu

Stainless steels are very unique in that they offer a wide range and combination of resistance to corrosion, resistance to oxidation at high temperature and good…

Abstract

Stainless steels are very unique in that they offer a wide range and combination of resistance to corrosion, resistance to oxidation at high temperature and good mechanical properties at room temperature. With rapid industrialization all over the world, these very properties have led to extensive use of stainless steels in different industries. Austenitic stainless steels containing molybdenum exhibit corrosion resistance in both sulphuric acid and nitric acid. Stainless steel undergoes severe attack in sulphuric acid having concentrations in the range of 20‐85 per cent, whereas they are immune to nitric acid in any concentration. However, sensitized stainless steels are prone to intergranular attack in acids, even in nitric acid. Further, the attack is aggravated in the presence of aggressive ions. Study of the behaviour of stainless steels in a mixture of acids (nitric and sulphuric acid) is lacking in the literature. This paper, therefore, discusses the performance of AISI‐316 and 316‐L in sulphuric acid and nitric acid and a mixture thereof at room temperature. It is observed that the steels are quite resistant to sulphuric acid and nitric acid, but in the acid mixture they are not so resistant, especially in AISI‐316 SS in respect of corrosion resistance, even in acid mixture containing C1 and Cu++ ions.

Details

Anti-Corrosion Methods and Materials, vol. 44 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 7 November 2016

Somrerk Chandra-ambhorn, Wisarut Wachirasiri and Gobboon Lothongkum

This paper aims to construct the E-pH diagrams for AISI 316L stainless steel in chloride solutions containing SO42− ions and therefore investigate the role of SO42− ions…

Abstract

Purpose

This paper aims to construct the E-pH diagrams for AISI 316L stainless steel in chloride solutions containing SO42− ions and therefore investigate the role of SO42− ions on pitting corrosion of stainless steel.

Design/methodology/approach

A cyclic potentiodynamic polarisation method was performed to obtain polarisation curves at different pH. From these curves, corrosion, primary passivation, pitting and repassivation potentials were determined and plotted as a function of pH giving the E-pH diagram.

Findings

The addition of SO42− ions to 10,650 ppm NaCl solution up to 3,000 ppm widened the passivation regime of the E-pH diagram mainly by shifting the pitting corrosion potential to the noble direction. This indicated the inhibiting role of SO42− on the nucleation of new pits in the transpassive region. It also stabilised the pitting corrosion potential at the pH ranging from 5 to 11. However, at pH 7, it caused the pit area to increase, implying the catalytic role of SO42− on the pit growth. Finally, it did not change the types of ions dissolved in solutions after pitting.

Practical implications

The diagrams can be used as a guideline in industries to determine the passivation regime of the AISI 316L stainless steel in chloride- and sulphate-containing solutions.

Originality/value

This paper reported the E-pH diagrams for the AISI 316L stainless steel in chloride solutions containing SO42− ions. The roles of pH and SO42− ions on pitting corrosion were innovatively discussed using a point defect model.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 1 April 2003

Halit Dogan, Fehim Findik and Ahmet Oztarhan

Coating is a technique employed for the surface of materials to have thermal insulation, hot corrosion and oxidation resistance. Ion implantation forms modifications in…

Abstract

Coating is a technique employed for the surface of materials to have thermal insulation, hot corrosion and oxidation resistance. Ion implantation forms modifications in surface composition or morphology of solids which yield to a change of physical and especially mechanical properties such as hardness and modulus of elasticity. The objective of this investigation is to concentrate on the friction and wear behaviour of TiN, N2 and Zr implanted and TiN and Tinalox PVD coated 316L stainless steel and compare with a substrate. Mainly stainless steels were of attraction, because they frequently demonstrate a poor tribological behaviour, which can be enhanced when they are hardened by incorporating N2, TiN Tinalox and Zr and forming a hardened surface zone.

Details

Industrial Lubrication and Tribology, vol. 55 no. 2
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 25 February 2014

Tadeusz Hryniewicz and Krzysztof Rokosz

Corrosion resistance measurements were performed on AISI 316L stainless steel biomaterial samples after three types of treatments: abrasive finishing (MP), standard…

Abstract

Purpose

Corrosion resistance measurements were performed on AISI 316L stainless steel biomaterial samples after three types of treatments: abrasive finishing (MP), standard electropolishing (EP), and magnetoelectropolishing (MEP). The corrosion studies were carried out in Ringer's solution at a room temperature. Potentiodynamic plots obtained were the basis for the analysis of measurement accuracy and uncertainty with the statistical tests results done in Statistica 64/10 software. The results of corrosion studies indicate a significant difference in the breaking potential (Epit) values, dependent on surface treatment. The highest mean values have been obtained on samples after MEP (Epit=961 mV), much lower – after a standard electropolishing EP (Epit=525 mV), and the lowest – after the abrasive treatment MP (Epit=222 mV), all of them measured against a saturated calomel electrode SCE potential. The corrosion results obtained are well correlated with the nanoindentation measurement results (Young's modulus and nanohardness). The paper aims to discuss these issues.

Design/methodology/approach

The AISI 316L austenitic stainless steel samples served for the study. There were 11 (MP) and 14 (EP) samples used for each of the treatment, and 31 samples used for magnetoelectropolishing MEP. All polarization measurements were made after one hour immersion in the Ringer's solution. Statistical tests were used to treat the results obtained.

Findings

After magnetoelectropolishing MEP130, the pitting corrosion resistance is much better than that after abrasive polishing MP and/or a standard electropolishing EP130. It was proved on a big statistical sample that the pitting corrosion potential Epit after MEP130 is over 1.8 times higher than that after EP130 and over 4.3 times higher than that after MP. The results obtained are in good agreement with the nanoindentation measurement results.

Originality/value

This is an original study of the corrosion resistance of AISI 316L SS in Ringer's solution. The breaking potential Eb obtained is comparable with that of NiTi alloys, not reported anywhere before. The results have been well confirmed statistically (on 31 samples after MEP).

Details

Anti-Corrosion Methods and Materials, vol. 61 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 7 January 2019

Mustafa Öcal and Recep Sadeler

The purpose of this study is to describe the environmentally assisted cracking (EAC) of AISI 316L stainless steel as bare and coated cases in several corrosion…

Abstract

Purpose

The purpose of this study is to describe the environmentally assisted cracking (EAC) of AISI 316L stainless steel as bare and coated cases in several corrosion environments. The main purpose of this study is to extend the lifespan of 316L material under corrosive fatigue in sodium chloride environments.

Design/methodology/approach

Fatigue tests carried out by using a Schenk type plane bending fatigue machine made by Tokyokoki Co. A scanning electron microscope (SEM) was used to observe the fracture surfaces and tested specimen surfaces. The micro-Vickers hardness of specimens was measured by using a PC-controlled Buehler–Omnimet tester.

Findings

Under reciprocating bending condition (R = −1) the behavior of 316L SS bare samples and 316L SS coated with Al-5%Mg samples were investigated comparatively at room temperature in ambient air and in several corrosion solutions. The results obtained from the data showed that Al-5Mg coating procedure significantly stabilized the 316L SS even in the most aggressive environment 5 per cent NaCl solution as compared with bare samples.

Originality/value

Al-5Mg coating showed a stable structure under the corrosion liquids used in the experiments. The coating material served as a stable barrier between the base material and the corrosion fluid, thus ensuring a tightness even in long-term tests below the endurance limit.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 18 April 2017

Marco Montani, Ali Gökhan Demir, Ehsan Mostaed, Maurizio Vedani and Barbara Previtali

This paper aims to investigate the processability by selective laser melting (SLM) of materials of potential interest for innovative biodegradable implants, pure Fe and…

Abstract

Purpose

This paper aims to investigate the processability by selective laser melting (SLM) of materials of potential interest for innovative biodegradable implants, pure Fe and pure Zn. The processability of these materials is evaluated with a more established counterpart in permanent implants, stainless steel. In particular, the processing conditions were studied to reduce porosity due to incomplete fusion of the powder.

Design/methodology/approach

In the first phase of the experiments, SLM of AISI 316L was studied through design of experiments method. The study was used to identify the significant parameters in the experimental range and estimate the fluence ranges for pure Fe and pure Zn using the lumped heat capacity model. In the second phase, SLM of pure Fe and pure Zn were studied using estimated fluence ranges. In the final phase, best conditions were characterized for mechanical properties.

Findings

The results showed that complete melting of AISI 316L and pure Fe could be readily achieved, whereas laser melting generated a foam-like porous structure in Zn samples. The mechanical properties of laser melt implant materials were compared to as-cast and rolled counterparts. Laser melted AISI 316L showed superior mechanical performance compared to as-cast and rolled material, whereas Fe showed mechanical performance similar to rolled mild steel. Despite 12 per cent apparent porosity, laser melted Zn exhibited superior mechanical properties compared to as-cast and wrought material because of reduced grain size.

Originality/value

The paper provides key processing knowledge on the SLM processability of new biodegradable metals, namely, pure Fe, which has been studied sparingly, and pure Zn, on which no previous work is available. The results prefigure the production of new biodegradable metallic implants with superior mechanical properties compared to their polymeric counterparts and with improved degradation rates compared to magnesium alloys, the reference material for biodegradable metals.

Details

Rapid Prototyping Journal, vol. 23 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

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