Multi-method approach to assess the corrosion behavior of a coated WE43 Mg alloy

CORROSION ◽  
10.5006/3629 ◽  
2020 ◽  
Author(s):  
Michael Höhlinger ◽  
Mark Bruns ◽  
Lukas Dahlem ◽  
Sannakaisa Virtanen
Keyword(s):  
Mass Loss ◽  
Corrosion Behavior ◽  
Open Circuit ◽  
Dissolution Behavior ◽  
Functional Coatings ◽  
Ion Release ◽  
Critical Issues ◽  
Immersion Testing ◽  
Multi Method Approach ◽  
Release Data

Developing appropriate and functional coatings for Mg-alloys, such as WE43, in view of controlling the degradation rate in biodegradable applications, requires a realistic understanding of the corrosion processes. While conventional methods such as electrochemical measurements can already give a good estimation about the protectiveness of coatings, immersion tests are also required to simulate a more realistic corrosion scenario (i.e., open-circuit dissolution as a function of time). Mass-loss experiments are a well-established method to determine the total corrosion rates at the end of such tests. However, these tests provide a very static result and may be difficult to interpret depending on the dissolution behavior of the coatings. Therefore, we present an analysis of an experimental approach to compare electrochemical data with immersion testing, in which mass loss, hydrogen evolution and ion release data were collected for each sample. Corrosion behavior was studied for bare WE43 alloy as well as for samples with different types of surface pre-treatments and coatings. Critical issues in the different experimental approaches are discussed.

scholarly journals Bioactive Plasma Coatings on Orthodontic Brackets: In Vitro Metal Ion Release and Cytotoxicity

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 857
Author(s):  
Lasni Samalka Kumarasinghe ◽  
Neethu Ninan ◽  
Panthihage Ruvini Lakshika Dabare ◽  
Alex Cavallaro ◽  
Esma J. Doğramacı ◽  
...  
Keyword(s):  
Metal Ion ◽  
Prolonged Exposure ◽  
Orthodontic Brackets ◽  
Plasma Polymer ◽  
Functional Coatings ◽  
Key Factors ◽  
Ion Release ◽  
Metal Ion Release ◽  
Surface Functionalisation

The metal ion release characteristics and biocompatibility of meta-based materials are key factors that influence their use in orthodontics. Although stainless steel-based alloys have gained much interest and use due to their mechanical properties and cost, they are prone to localised attack after prolonged exposure to the hostile oral environment. Metal ions may induce cellular toxicity at high dosages. To circumvent these issues, orthodontic brackets were coated with a functional nano-thin layer of plasma polymer and further immobilised with enantiomers of tryptophan. Analysis of the physicochemical properties confirmed the presence of functional coatings on the surface of the brackets. The quantification of metal ion release using mass spectrometry proved that plasma functionalisation could minimise metal ion release from orthodontic brackets. Furthermore, the biocompatibility of the brackets has been improved after functionalisation. These findings demonstrate that plasma polymer facilitated surface functionalisation of orthodontic brackets is a promising approach to reducing metal toxicity without impacting their bulk properties.

Effect of Interface States on the Open-Circuit Volatage in a-Si:H/c-Si Heterojunction Solar Cells

2012 ◽  
Vol 485 ◽  
pp. 454-456
Author(s):  
Lan E Luo ◽  
Chun Liang Zhong
Keyword(s):  
Open Circuit Voltage ◽  
Minority Carrier ◽  
Interface States ◽  
Open Circuit ◽  
Band Offset ◽  
Heterojunction Solar Cells ◽  
Conduction Band Offset ◽  
Photovoltaic Application ◽  
Critical Issues ◽  
Recombination Centers

The properties of the a-Si:H/c-Si interface are one of the critical issues for the photovoltaic application. The effects of the interface states on the open-circuit voltage VOC were performed by a set of simulations. VOC decreases with Dit increasing, especially at high values of Dit, since the interface states act as recombination centers to decrease the excess minority carrier density in c-Si. Since the conduction band offset ∆EC can saturate part of interface states, VOC increasing with ∆EC increasing.

Effects of hydroxyapatite content on mechanical properties and in-vitro corrosion behavior of ZK60/HA composites

2020 ◽  
Vol 111 (8) ◽  
pp. 621-631
Author(s):  
Jie Teng ◽  
Zili Xu ◽  
Jinlong Su ◽  
Yuan Li
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Measurement ◽  
X Ray Diffraction ◽  
Corrosion Morphology ◽  
Hardness Tests ◽  
Zk60 Alloy ◽  
Immersion Testing

Abstract In this study, hydroxyapatite-reinforced ZK60 Mg alloybased composites were fabricated via a powder metallurgy route. The mechanical properties of these composites were studied by compressive tests and hardness tests. The in-vitro corrosion behavior was also investigated using immersion testing and electrochemical measurement. The influence of hydroxyapatite content on the mechanical properties and invitro corrosion behavior was evaluated. The microstructure and corrosion morphology were characterized by means of X-ray diffraction, optical and scanning electron microscopy. The results showed that the composite materials with 10 wt.% hydroxyapatite exhibited a better combination of mechanical strength and corrosion resistance. Compared with ZK60 alloy, the addition of 10 wt.% hydroxyapatite resulted in an increase in corrosion resistance by 38.6%.

scholarly journals The Corrosion Behavior of Sputter-Deposited Nanocrystalline W-Cr Alloys in Nacl and NaohaSolutions

1970 ◽  
Vol 25 ◽  
pp. 53-61
Author(s):  
Minu Basnet ◽  
Jagadeesh Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Chromium Content ◽  
Open Circuit ◽  
Nacl Solution ◽  
Corrosion Rates ◽  
Naoh Solution ◽  
Order Of Magnitude ◽  
Sputter Deposited

The corrosion behavior of the sputter-deposited nanocrystalline W-Cr alloys wasstudied in 0.5 M NaCl and alkaline 1 M NaOH solutions at 25°C, open to air usingimmersion tests and electrochemical measurements. Chromium metal acts synergisticallywith tungsten in enhancing the corrosion resistance of the sputter-deposited W-Cr alloys soas to show higher corrosion resistance than those of alloy-constituting elements in both 0.5M NaCl and 1 M NaOH solutions. In particular, the nanocrystalline W-Cr alloys containing25-91 at% chromium showed about one order of magnitude lower corrosion rates (that is,about 1-2 × 10-3 mm.y-1) than those of tungsten and chromium metals even for prolongedimmersion in 0.5 M NaCl solution at 25°C. On the other hand, the corrosion rate of thesputter-deposited W-Cr alloys containing 25-75 at % chromium was decreased significantlywith increasing chromium content and showed lowest corrosion rates (that is, 1.5-2.0 × 10-3 mm.y-1) after immersed for prolonged immersion in 1 M NaOH solution. The corrosion ratesof these nanocrystalline W-(25-75)Cr alloys are nearly two orders of magnitude lower thanthat of tungsten and more than one order of magnitude lower corrosion rate than that ofsputter-deposited chromium metal in 1 M NaOH solution. The corrosion-resistant of all theexamined sputter-deposited W-Cr alloys in 0.5 M NaCl solution is higher than in alkaline 1M NaOH solution at 25°C. Open circuit potentials of all the examined W-Cr alloys areshifted to more noble direction with increasing the chromium content in the alloys afterimmersion for 72 h in both 0.5 M NaCl and 1 M NaOH solutions at 25°C, open to air.Keywords: Sputter deposition, nanocrystalline W-Cr alloys, corrosion test, electrochemicalmeasurement, NaCl and NaOH solutions.DOI:  10.3126/jncs.v25i0.3300Journal of Nepal Chemical Society Volume 25, 2010 pp 53-61

Prediction and Measurement of Corrosion Rates of Stainless Steel in Concentrated Sulfuric Acid

CORROSION ◽  
10.5006/0709 ◽  
2013 ◽  
Vol 69 (6) ◽  
pp. 543-550 ◽  
Author(s):  
S. Jones ◽  
K. Coley ◽  
J. Kish
Keyword(s):  
Stainless Steel ◽  
Sulfuric Acid ◽  
Corrosion Behavior ◽  
Electrochemical Behavior ◽  
Open Circuit Potential ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Corrosion Rates ◽  
Transient Nature ◽  
Concentrated Sulfuric Acid

When exposed to concentrated sulfuric acid, stainless steel exhibits unique electrochemical behavior. This behavior can be observed as an oscillation in open-circuit potential between the active and passive states. The transient nature of the corrosion behavior under these conditions results in a distinct challenge for measuring and predicting corrosion rates. Using a series of commercial alloys with various nickel contents, this paper outlines the utilization of electrochemical experimentation to refine the prediction of corrosion rates. The paper also discusses some of the difficulties associated with many traditional electrochemical techniques such as potentiodynamic scans when used for characterizing systems that undergo oscillations in open-circuit potential.

Effect of Deformation on the Corrosion Behavior of Chromium Bronze

2013 ◽  
Vol 303-306 ◽  
pp. 2465-2468
Author(s):  
Ya Ni Zhang ◽  
Dang Hui Wang ◽  
Tian Han Xu
Keyword(s):  
Corrosion Resistance ◽  
Mass Loss ◽  
Corrosion Behavior ◽  
Initial Stage ◽  
Corrosion Scales ◽  
Rolled Specimen ◽  
Cold Rolled ◽  
Chromium Bronze ◽  
Cold Worked ◽  
Cold Rolled Specimen

The service life of material is much related with its corrosion resistance. Thus, the investigation on corrosion behavior is important for the better use of material. In this paper, the corrosion behavior of deformed chromium bronze experienced different processing was investigated in NaCl environment using electrochemical measurements and mass-loss tests. It has showed that the potentiodynamic polarization curves of cold rolled specimen coincide with that of cold worked specimen in two concentration of NaCl solution. The last cold working has little effect on the electrochemical behavior of cold rolled chromium bronze.The NaCl fog experiment showed that the corrosion resistance of cold rolled specimen is slightly better than that of cold worked specimen, and the mass-loss for two kinds of specimen are similar in the initial stage but the gap is increasing with corrosion time. The corrosion scales on the surface of specimen, accumulated in the form of island produced in the NaCl fog experiment , has little hindered effect on corrosion behavior.

Polymeric nanoparticles-based multi-functional coatings on NiTi alloy with nickel ion release control, cytocompatibility, and antibacterial performance

2019 ◽  
Vol 43 (3) ◽  
pp. 1551-1561 ◽  
Author(s):  
Long Meng ◽  
Yunan Wu ◽  
Kai Pan ◽  
Ye Zhu ◽  
Xiaojie Li ◽  
...  
Keyword(s):  
Polymeric Nanoparticles ◽  
Niti Alloy ◽  
Antibacterial Properties ◽  
Functional Coatings ◽  
Ion Release ◽  
Nickel Ion ◽  
Antibacterial Performance ◽  
Release Control

Photo-cross-linked quaternized copolymer coatings on NiTi alloy show prominent inhibition of nickel ion release and antibacterial properties.

Electrochemical Behavior of Fe-Cr-Mo-C-B Amorphous Alloy Coating in HCl Solution

2011 ◽  
Vol 291-294 ◽  
pp. 18-23
Author(s):  
Qing Jun Chen ◽  
Lin Li Hu ◽  
Xian Liang Zhou ◽  
Xiao Zhen Hua
Keyword(s):  
Amorphous Alloy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Low Frequency ◽  
Alloy Coating ◽  
Open Circuit ◽  
Polarization Curves ◽  
Hcl Concentration ◽  
Hcl Solution

The corrosion behavior of Fe44Cr16Mo16C18B6amorphous alloy coating was studied by electrochemical polarization curves and electrochemical impedance spectroscopy (EIS) in different HCl concentration solution at room temperature. Experimental results show that the polarization curves of the coating present a wide passivation range under open circuit potential and icorrincrease from 1.049×10-5A/cm2to 1.487×10-5A/cm2with HCl solution from 0.5M to 2.0M. The EIS of coating are composed of high-frequency inductive loop and low-frequency capacitance arc, which is different from the EIS of other amorphous alloys, the Rt is up to 5789Ω·cm2in 2M HCl solution. The especial equivalent circuit model R(RL)(Q(R(QRW))) can better interpret the corrosion behavior of the amorphous alloy coating.

Comparative Study of the Corrosion Behavior of Low-Nickel AISI 202 and Conventional AISI 304 Stainless Steels in Citric Acid Using Electrochemical Techniques

2016 ◽  
Vol 835 ◽  
pp. 131-135 ◽  
Author(s):  
Francis Mulimbayan ◽  
Manolo G. Mena
Keyword(s):  
Stainless Steel ◽  
Citric Acid ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Corrosion Current ◽  
Open Circuit ◽  
Corrosion Mechanism ◽  
Protective Film ◽  
Aisi 304

Stainless steel (SS) is one of the most commonly used metallic food contact materials. It may be classified based on its microstructure whether ferritic, austenitic, martensitic, duplex or precipitation hardened. Austenitic SS, among mentioned grades, has the largest contribution to market due to its numerous industrial and domestic applications. In this study, the corrosion behavior of AISI 202 SS – a cheaper grade of stainless steel, in three different solution temperatures of citric acid was investigated using different electrochemical techniques such as open-circuit potential (OCP) measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results were compared to that obtained from conventional AISI 304 SS. OCP, polarization and impedance measurements agreed that AISI 202 SS has comparable resistance to that of AISI 304 SS in citric acid at ambient temperature and at 50 °C. At 70 °C, results of OCP measurements suggest that AISI 304 SS exhibited greater performance as indicated by more positive OCP values in the designated solution. EIS results indicate that the two alloys have identical corrosion resistance even at 70 °C as indicated by their comparable polarization resistance (Rp). The corrosion mechanism in both alloys is charge-transfer controlled as indicated by depressed semi-circular appearance of the generated Nyquist plots. The values of corrosion current densities (icorr) extracted from polarization curves indicate that the initial corrosion rates were higher in AISI 304 than AISI 202 SS suggesting that formation of more protective film may have occurred on the former alloy.

Electrochemical Investigation of the Effects of Acid Concentration and Dissolved Oxygen on the Corrosion Behavior of Austenitic Low-Nickel Stainless Steels in Citric Acid

2016 ◽  
Vol 835 ◽  
pp. 115-120
Author(s):  
Francis Mulimbayan ◽  
Manolo G. Mena
Keyword(s):  
Corrosion Resistance ◽  
Citric Acid ◽  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Human Consumption ◽  
Face Centered Cubic

All materials which are intended to have in contact with food and other commodities produced or processed for human consumption are called food contact materials (FCM’s). Stainless steel (SS) – a widely known metallic FCM is used mainly in processing equipment, containers and household utensils. It is known for having numerous industrial and domestic applications worldwide due to its special characteristics of having notable corrosion resistance. However, this corrosion resistance is not all-encompassing since SS may still undergo degradation when subjected to a specific corrosion-inducing environment. SS may be classified according to its microstructure. If the atoms which make up the SS can be viewed as having a face-centered cubic structure, then the alloy is said to be austenitic. This SS grades include the conventional 300-series and the newly-developed 200-series. The former has superior corrosion resistance while the latter is far cheaper. In this study, the corrosion behavior of AISI 202 SS in two different levels of dissolved oxygen (O2) and three acid concentrations was investigated using electrochemical techniques, namely, open-circuit potential (OCP) measurements and electrochemical impedance spectroscopy (EIS). As the concentration of citric acid is increased, the measured OCP values of the alloy decreased and the polarization resistance (Rp) decreased, indicating decrease in alloy stability and decline in the corrosion resistance, respectively. With regards to effects of dissolved O2, results revealed that increasing the level of dissolved O2 has consequently increased the polarization resistance and shifted the OCP to more positive values. All the generated Nyquist plots exhibited a depressed capacitive loops indicating that corrosion in the designated solution occurred with charge transfer as the rate-determining step.

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