scholarly journals Effect of Alkaline Artificial Seawater Environment on the Corrosion Behaviour of Duplex Stainless Steel 2205

2020 ◽  
Vol 10 (15) ◽  
pp. 5043
Author(s):  
Tien Tran Thi Thuy ◽  
Krishnan Kannoorpatti ◽  
Anna Padovan ◽  
Suresh Thennadil
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Hydrogen Sulphide ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Artificial Seawater ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Desulfovibrio Vulgaris ◽  
Alkaline Environments

Sulphate reducing bacteria (SRB) can be found in alkaline environments. Due to their metabolite products such as hydrogen sulphide, the corrosion behaviour of materials in alkaline environments may be affected by the presence of SRB. This study focuses on the investigation of corrosion behaviour of duplex stainless steel DSS 2205 in nutrient rich artificial seawater containing SRB species, Desulfovibrio vulgaris, at different alkaline conditions with pH range from 7 to 10. The open circuit potential value (OCP), sulphide level and pH were recorded daily. Confocal laser scanning microscopy (CLSM) was used to study the adhesion of SRB on the DSS 2205 surface. Electrochemical impedance spectroscopy (EIS) was used to study the properties of the biofilm. Potentiodynamic polarization was used to study the corrosion behaviour of material. Inductively coupled plasma mass was used to measure the concentration of cations Fe, Ni, Mo, Mn in the experimental solution after 28 days. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used for surface analysis. The results showed that D. vulgaris are active in an alkaline environment with pH 7–9. However, at pH 10, D. vulgaris activity exhibited an 8-day lag. The corrosion rate of DSS 2205 at pH 9 was higher than at other pH environments due to a higher dissolved concentration of hydrogen sulphide.

Corrosion behavior of a new 25Cr-3Ni-7Mn-0.66 N duplex stainless steel in artificial seawater

2021 ◽  
Vol 63 (6) ◽  
pp. 505-511
Author(s):  
Songkran Vongsilathai ◽  
Anchaleeporn Waritswat Lothongkum ◽  
Gobboon Lothongkum
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Passive Film ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Melting Furnace ◽  
Artificial Seawater ◽  
Vacuum Arc ◽  
Significant Difference ◽  
Type Semiconductor

Abstract A new duplex 25Cr-3Ni-7Mn-0.66 N alloy was prepared in a vacuum arc re-melting furnace and characterized by metallographic and EPMA methods. Its corrosion behavior was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and a Mott-Schottky (M-S) analysis in artificial seawater at room temperature and compared with those of super and normal commercial duplex stainless steel (SDSS and DSS). No significant difference in the open circuit potentials and pitting potentials was observed. Its passive film current density lies between those of SDSS and DSS. This was confirmed by EIS analysis. A pit attack was observed on the δ-phase for all duplex samples, because the PREN16 of the δ-phase was lower than that of the γ-phase. From the Mott-Schottky analysis, the passive films were found to be composed of bi-layer structures, a p-type semiconductor inner layer, and a n-type semiconductor outer layer. The degree of defect as well as the effect of nitrogen in passive film layer are discussed with respect to the point defect model.

scholarly journals Effect of pH regulation by sulfate-reducing bacteria on corrosion behaviour of duplex stainless steel 2205 in acidic artificial seawater

2021 ◽  
Vol 8 (1) ◽  
pp. 200639
Author(s):  
T. T. T. Tran ◽  
K. Kannoorpatti ◽  
A. Padovan ◽  
S. Thennadil
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Corrosion Behaviour ◽  
Ph Regulation ◽  
Low Ph ◽  
Corrosion Process ◽  
Artificial Seawater ◽  
Effect Of Ph ◽  
Sulfate Reducing ◽  
Reducing Bacteria

Sulfate-reducing bacteria (SRB) can regulate environmental pH because of their metabolism. Because local acidification results in pitting corrosion, the potential capacity of pH regulation by SRB would have important consequences for electrochemical aspects of the bio-corrosion process. This study focused on identifying the effect of pH on the corrosion of duplex stainless steel 2205 in a nutrient-rich artificial seawater medium containing SRB species, Desulfovibrio vulgaris . Duplex stainless steel samples were exposed to the medium for 13 days at 37°C at pH ranging from 4.0 to 7.4. The open-circuit potential value, sulfide level, pH and number of bacteria in the medium were recorded daily. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to study the properties of the biofilms at the end of the experiments and the corrosion behaviour of the material. Inductively coupled plasma mass spectrometry was used to measure the concentration of cations Fe, Ni, Mo, Mn, Cr in the experimental solution after 13 days. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX) were used for surface analysis. The results showed the pH changed from acidic values set at the beginning of the experiment to approximately pH 7.5 after 5 days owing to bacterial metabolism. After 13 days, the highest iron concentration was in the solution that was initially at pH 4 accompanied by pitting on the stainless steel. Sulfur was present on all specimens but with more sulfur at pH 4 in the EDX spectra. EIS showed the film resistance of the specimen at pH 4 was much lower than at pH 7.4 which suggests the corrosion resistance of the stainless steel was better at higher pH. The results of this study suggest that the corrosion process for the first few days exposure at low pH was driven by pH in solution rather than by bacteria. The increasing pH during the course of the experiment slowed down the corrosion process of materials originally at low pH. The nature and mechanism of SRB attack on duplex stainless steel at different acidic environments are discussed.

scholarly journals Antimicrobial and Anticorrosion Activity of a Novel Composite Biocide against Mixed Bacterial Strains in Taiwanese Marine Environments

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6156
Author(s):  
Soul-Yi Chang ◽  
Shih-Yen Huang ◽  
Yu-Ren Chu ◽  
Shun-Yi Jian ◽  
Kai-Yin Lo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Laser Scanning Microscopy ◽  
304 Stainless Steel ◽  
Single Type ◽  
Confocal Laser ◽  
Subtropical Climate ◽  
Marine Environments ◽  
Bacterial Strains

Taiwan is an island with a humid subtropical climate. The relatively warm seawater results in biofouling of the surfaces of marine facilities. Biocide application is a common practice for combating and eliminating adhesive fouling. However, a single type of biocide may have limited antimicrobial effects due to the relatively high microbial diversity in marine environments. Therefore, applying a mixture of various biocides may be necessary. In this study, the antimicrobial and anticorrosion properties of a newly designed composite biocide, namely a combination of thymol and benzyldimethyldodecylammonium chloride, were investigated by applying the biocide to 304 stainless steel substrates immersed in inocula containing bacterial strains from Tamsui and Zuoying harbors. The ability of 3TB and 5TB treatments to prevent sessile cells and biofilm formation on the 304 stainless steel coupon surface was determined through scanning electron microscopy investigation. In addition, confocal laser scanning microscopy indicated that the 5TB treatment achieved a greater bactericidal effect in both the Tamsui and Zuoying inocula. Moreover, electrochemical impedance spectroscopy revealed that the diameter of the Nyquist semicircle was almost completely unaffected by Tamsui or Zuoying under the 5TB treatment. Through these assessments of antimicrobial activity and corrosion resistance, 5TB treatment was demonstrated to have superior bactericidal activity against mixed strains in both southern and northern Taiwanese marine environments.

scholarly journals Development of a methodology for measuring the evolution of duplex stainless-steel low-temperature plasma nitrided phases expansion using confocal laser scanning microscopy

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Carlos Eduardo Alves Feitosa ◽  
Rodrigo Perito Cardoso ◽  
Silvio Francisco Brunatto
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Duplex Stainless Steel ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Innovative Methodology ◽  
Different Response

Samples of duplex stainless steel SAF 2507 were low-temperature plasma nitrided to characterize separately, on the surface, the behavior of its ferrite and austenite phases in relation to two competing processes, that is, one caused by enrichment by nitrogen, resulting in possible expansion, and the other caused by the removal of superficial atoms via sputtering, which may lead to the retraction of the studied phases. Since these phases have different different compositions and crystalline structures, of which the diffusivity and solubility of nitrogen in them are dependent, a different response for each type of phase can be expected. In this article, an innovative methodology has been developed to quantify and clarify which effects are predominant in the course of nitriding for each of these phases. The results indicate that phase expansion prevails over sputtering.

scholarly journals A study of bacteria adhesion and microbial corrosion on different stainless steels in environment containing Desulfovibrio vulgaris

2021 ◽  
Vol 8 (1) ◽  
pp. 201577
Author(s):  
T. T. T. Tran ◽  
K. Kannoorpatti ◽  
A. Padovan ◽  
S. Thennadil
Keyword(s):  
Stainless Steel ◽  
Surface Properties ◽  
Passive Film ◽  
Stainless Steels ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Bacterial Attachment ◽  
Alloying Elements ◽  
Desulfovibrio Vulgaris ◽  
Microbial Corrosion

Stainless steel is an important material used in many applications due to its mechanical strength and corrosion-resistant properties. The high corrosion resistance of stainless steel is provided by the passive film. Different stainless steels have different alloy elements and surface properties which could have a significant influence on bacterial attachment to the surface and thus might result in different microbial corrosion behaviours. In this study, the effect of adhesion of sulfate-reducing bacteria (SRB) on corrosion behaviour in artificial seawater on different stainless steels was investigated. Stainless steel materials used were SS 410, SS 420, SS 316 and DSS 2205 and pure chromium. The contact angle was measured to study the effect of surface properties of materials. Adhesion was measured by counting cells attached to the surface of materials. The corrosion behaviour of the materials was measured by electrochemical testing including measuring open circuit potential, electrochemical impedance spectroscopy and potentiodynamic behaviour. The long-term corrosion behaviour of each material was studied after six months of exposure by measuring weight loss and surface analysis with scanning electron microscope with energy-dispersive X-ray analysis. Hydrophobicity had a strong effect on bacterial attachment. Alloying elements e.g. nickel also had shown its ability to attract bacteria to adhere on the surface. However, the corrosion rate of different materials is determined not only by bacterial attachment but also by the stability of the passive film which is determined by the alloying elements, such as Mo and Cr. Chromium showed high resistance to corrosion, possibly due to toxicity on bacterial attachment. The nature of bacterial attachment and corrosion behaviour of the materials are discussed.

Low velocity oxy fuel spraying of hydroxyapatite coating on a multifunctional UNS S31254 austenitic stainless steel

2021 ◽  
pp. 095441192110157
Author(s):  
Srikant Tiwari ◽  
Suryanarayan B Mishra
Keyword(s):  
Stainless Steel ◽  
Calcium Phosphate ◽  
Austenitic Stainless Steel ◽  
Bacterial Adhesion ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Steel Substrate ◽  
The Body ◽  
Low Velocity ◽  
Uncoated Steel

Artificial material such as stainless steel (SS) is widely used for orthopaedic applications owing to its superior properties, ease of fabrication and lower cost. However, in the body environment, stainless steel can leach toxic elements such as nickel and chromium. To prevent this, a hydroxyapatite (HAp) coating having chemical characteristics very similar to the human bone was deposited on a medical-grade UNS S31254 austenitic stainless steel by a Low-velocity oxy-fuel spray gun (LVOF). The coating was characterised by using a field emission scanning electron microscope (FESEM), X-ray diffractometer (XRD) and Fourier transform infrared spectroscope (FTIR). The adhesion strength, microhardness and corrosion behaviour were studied using the Tensometre, Vickers microhardness tester and potentiodynamic polarisation with electrochemical impedance spectroscope. The bacterial adhesion and bioactivity of the coating were also evaluated. The LVOF sprayed HAp coating has shown better corrosion resistance, higher bioactivity and higher hardness than the uncoated steel. The presence of tricalcium phosphate, octa-calcium phosphate (OCP) and tetra-calcium phosphate (TTCP) was found in the coating. LVOF sprayed HAp coating is also found suitable in lowering the bacterial adhesion on the steel substrate.

scholarly journals Influence of Aging on Corrosion Behaviour of the 6061 Cast Aluminium Alloy

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1821
Author(s):  
Ting He ◽  
Wei Shi ◽  
Song Xiang ◽  
Chaowen Huang ◽  
Ronald G. Ballinger
Keyword(s):  
Aluminium Alloy ◽  
Laser Scanning ◽  
Corrosion Behaviour ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
The Matrix ◽  
6061 Aluminium Alloy

The influence of AlFeSi and Mg2Si phases on corrosion behaviour of the cast 6061 aluminium alloy was investigated. Scanning Kelvin probe force microscopy (SKPFM), electron probe microanalysis (EPMA), and in situ observations by confocal laser scanning microscopy (CLSM) were used. It was found that Mg2Si phases were anodic relative to the matrix and dissolved preferentially without significantly affecting corrosion propagation. The AlFeSi phases’ influence on 6061 aluminium alloy local corrosion was greater than that of the Mg2Si phases. The corroded region width reached five times that of the AlFeSi phase, and the accelerating effect was terminated as the AlFeSi dissolved.

Tribocorrosion Behavior of SAF 2205 Duplex Stainless Steel in Artificial Seawater

2018 ◽  
Vol 28 (1) ◽  
pp. 414-422
Author(s):  
Ruipeng Gao ◽  
Eryong Liu ◽  
Yingxin Zhang ◽  
Lufa Zhu ◽  
Zhixiang Zeng
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Artificial Seawater ◽  
2205 Duplex Stainless Steel ◽  
Saf 2205

Surface Characterization of Incoloy 825 Ni-Based Alloy/2507 Super Duplex Stainless Steel Dissimilar Friction Stir Welds

CORROSION ◽  
10.5006/2755 ◽  
2018 ◽  
Vol 74 (11) ◽  
pp. 1259-1271 ◽  
Author(s):  
Jalal Kangazian ◽  
Morteza Shamanian ◽  
Ali Ashrafi
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Surface Characterization ◽  
Electrochemical Impedance ◽  
Friction Stir Weld ◽  
General Corrosion ◽  
Super Duplex Stainless Steel ◽  
Friction Stir ◽  
Surface Corrosion ◽  
Incoloy 825

Surface features of a dissimilar friction stir weld between Incoloy 825 Ni-based alloy and SAF 2507 super duplex stainless steel were investigated using scanning electron microscopy, microhardness test, cyclic potentiodynamic polarization, and electrochemical impedance spectroscopy. The surface of the weldment showed lower general corrosion resistance in comparison to the base metals. Areas under the weld shoulder exhibited weak pitting resistance because of the deformed structure and/or chromium nitride precipitates. Incoloy 825 located under the shoulder also displayed the highest susceptibility to pit growth because of the austenite matrix containing titanium nitride phases. Overall, the obtained results demonstrated that the friction stir welding method could significantly deteriorate the surface corrosion behavior of the processed regions.

Influence of the Electrolyte Composition on the Corrosion Behavior of Anodized AZ31B Magnesium Alloy

2020 ◽  
Vol 1012 ◽  
pp. 424-429
Author(s):  
Leandro Antonio de Oliveira ◽  
Renato Altobelli Antunes
Keyword(s):  
Magnesium Alloy ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Electrolyte Composition ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Mixed Solution ◽  
Protective Properties ◽  
Az31b Magnesium Alloy ◽  
Substrate Dissolution

Investigations have been performed to study the effects of the electrolyte composition on the properties of anodized films grown on AZ31B magnesium alloy. The corrosion protection ability of the oxide layers was explored by using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy. Film morphology was examined by scanning electron microscopy and confocal laser scanning microscopy. In spite of its higher roughness average, the film formed in the silicate and hydroxide mixed solution enhanced the protective properties of the anodized layer, thus reducing the substrate dissolution rate.

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