Corrosion - Science topic

Dear Dr. Smitha Shree Subramaniyam ,

I suggest you to have a look at the following, interesting doduments:

-What is Electrochemical Impedance Spectroscopy (EIS)? by BioLogic

Available at: https://www.biologic.net/topics/what-is-eis/

-Corrosion Testing via Electrochemical Impedance Spectroscopy (EIS) by vlci

Available at: https://vlci.biz/corrosion-testing-via-electrochemical-impedance-eis/

-Precautions for good impedance measurements (EIS) by BioLogic

Available at: https://www.biologic.net/documents/eis-precautions-electrochemistry-battery-application-note-5/

-Basics of Electrochemical Impedance Spectroscopy by Gamry Instruments

Available at: https://www.gamry.com/application-notes/EIS/basics-of-electrochemical-impedance-spectroscopy/

-Using Electrochemical Impedance Spectroscopy (EIS) Method for a Better Understanding of the Corrosion System by zerust

Available at: https://www.zerust.com/blog/2020/11/03/using-electrochemical-impedance-spectroscopy-eis-method-for-a-better-understanding-of-the-corrosion-system/

Enjoy reading and my best regards, Pierluigi Traverso.

Is the proposal still on ?

First of all, my colleague performed polarization in the Tafel range. At higher anode potentials, copper in solution shows the beginning of passivation. Try to limit the scope of the analysis and determine the parameters of the Tafel curve - also the corrosion rate. Linear polarization is a method that uses very small polarizations relative to the corrosion potential of +/- 20 mV. So I propose to repeat the measurement and present, first of all, the result on a double-linear scale rather than a linear-logarithmic scale.

stefan

Dear Dr. Yazid Amri ,

as I wrote in another similar question, I suggest you to have a look at the following, interesting documents:

-Application Note - Getting Started with Electrochemical Corrosion Measurement by Gamry Instruments

Available at: https://www.gamry.com/assets/Application-Notes/Getting-Started-with-Electrochemical-Corrosion-Measurement.pdf

-Tafel Plot and Evans Diagram by Palmsens

Available at: https://www.palmsens.com/knowledgebase-article/tafel-plot-and-evans-diagram/

Enjoy reading and my best regards, Pierluigi Traverso.

You can very simply determine the amount of iron oxide by the change in mass:

It is necessary to weigh the glass vessel with iron on an accurate scale before pouring water, and after the corrosion test, carefully drain the water and calcine the vessel with iron at 100-120° until completely dry and weigh it again. The difference in masses before and after corrosion will be the mass of iron oxide.

tq sir

yes, its why steel in concrete generally doesn't rust. Two causes of corrosion - 1) atmospheric carbon dioxide reduces the pH over time, note this will get worse as CO2 levels increase, and 2) chloride ingress, eg from the sea or chloride contamination in the mi, chlorides will depassivate the steel regardless of pH.

Phytochemicals present in the plant extract acts as a green corrosion inhibitor by providing barrier effect on the active sites of the metals thus preventing corrosion

Niksy Maria. -- I’m sending these for help study the corrosion of steel. Though I don’t know if either is suitable for your work, each seems to offer ideas for what’s useful to include. I have worked with ASTM and found their recommended conce established & and widely familiar. But on the latest tools and techniques. The last links address Galvanizaton

1)__ ASTM (this is a well establish US group who sets standards for measurement and analysis and evaluation.

“Environmental Factors Affecting the Corrosion of Galvanized Steel”

Galvanized steel samples are exposed for periods of up to 30 months at nine air monitoring sites in the St. Louis, MO area. Climatic and air quality data are recorded during the exposure periods and subjected to a rigorous evaluation to eliminate recording errors and to estimate missing values. Weight loss is used as the measure of zinc corrosion on the galvanized steel. The corrosion rate is evaluated with respect to fluxes of pollutants (sulfur oxides, nitrogen oxides, oxidants, and particles) to the galvanized steel during both wet and dry periods, (2) temperature, and (3) amount of rainfall at Lambert Field (airport). Different definitions of when the galvanized steel was wet are evaluated to determine the most likely “critical relative humidity.” A theoretical model of film buildup and dissolution is developed to explain how factors affect corrosion rates. Nonlinear and linear multiple regression techniques are used to determine the statistical significance of each factor.

2)__ Science Direct

Evolution of corrosion degradation in galvanised steel bolts exposed to a tropical marine environment. — The time-dependent degradation of galvanised steel bolts subjected to marine atmospheric exposure for a maximum period of 2 years in the Wenchang marine environment of Hainan province, South China, was investigated.

3)__ Estimating Galvanized Steels Service Life in Soil. — Due to varying physical and chemical characteristic of soil, it is difficult to predict underground corrosion rates. Even in very close proximity, soil content conditions can have significant variations. In order to predict the performance of hot-dip galvanized steel in the soil, you must first try and classify the soil to which the galvanized steel will be exposed. The properties of soil that have the most effect on the corrosion rate are aeration, moisture content (or time of wetness), pH, temperature, and resistivity.

4)__ Performance of Galvanized Steel in Different Environments. — Does hot-dip galvanized steel perform the same in any type of environment?

Hot-dip galvanized steel is specified in many different applications and environments. Exposure conditions include atmospheric, submerged applications, chemical environments, and soil. Although the galvanized coating provides a barrier and cathodic protection in each of these environments, the mechanism of corrosion protection can be different. Lets explore how the hot-dip galvanized coating protects the underlying steel in different environments.

Qanita Tayyaba

Cut out a sample with a weld seam and polish it. Cover with adhesive plastic film to cover the welding area. Paint the rest. Explore using normal methods.

If the corrosion is limited on nickel coating only, not onto aluminium substrate, then you can use equivalent weight and density of nickel. (then gram/cm^2/year or whatever would be of nickel, and cm/year would be also of nickel.

But if both nickel and aluminium are corroded, scenario would be much more complex, depending on what you are targeting to find out.

Dear Dr. Niu Ziyang ,

the more negative the standard electrode potential, the greater the tendency to form metal ions and hence to corrode. Corrosion potential indicates the tendency of metals to corrode, but it does not provide the rate of corrosion. Rate of corrosion is proportional to the rate of electron transferred between electrode and electrolyte. Rate of electron transfer is represented as current (I).

High corrosion potentials are good. The system will rather take up electrons than lose electrons, so a reduction is more likely. If the corrosion potential is dropping, it means that the sample is oxidizing and negative charges are accumulating in it.

For more details, please see the source:

-THE ELECTROCHEMISTRY OF CORROSION Edited by Gareth Hinds from the original work of J G N Thomas

Available at: http://resource.npl.co.uk/docs/science_technology/materials/life_management_of_materials/publications/online_guides/pdf/the_electrochemistry_of_corrosion.pdf

and

Corrosion Potential by Palmsens

Available at:

https://www.palmsens.com/knowledgebase-article/corrosion-potential/#:~:text=High%20corrosion%20potentials%20are%20good,charges%20are%20accumulating%20in%20it.

My best regards, Pierluigi Traverso.

This depends on equilibirium constant of Co-dissloution reaction as well as Co-Cl complex stability equilibrium constant. Going a bit deeper (say Tafel equation or Butler-Volmer), one needs to consider potential-current density diagram, and look at whether the situation lies on active, passive or transpassive region

Dear friend Jianming Wang

Ah, the intricate dance of corrosion in the realm of materials engineering! Distinguishing between galvanic corrosion, micro-galvanic corrosion, and selective corrosion in duplex stainless steel or High-Entropy Alloys (HEAs) requires a keen eye and a solid understanding of their nuances.

Let's break it down:

1. **Galvanic Corrosion**: Picture this as a classic case of mismatched partners in a corrosive tango. Galvanic corrosion occurs when two dissimilar metals or alloys are in contact in the presence of an electrolyte. One metal act as the anode (sacrificial metal), corroding to protect the cathodic metal. In duplex stainless steel or HEAs, galvanic corrosion may manifest at interfaces between dissimilar phases or compositions.

2. **Micro-Galvanic Corrosion**: Now, imagine this as a stealthy, microscopic version of galvanic corrosion. Micro-galvanic corrosion arises within a material due to microstructural variations, such as differences in composition, grain size, or precipitates. In HEAs, where multiple elements coexist in varying concentrations, micro-galvanic corrosion can occur between these microstructural features, leading to localized corrosion.

3. **Selective Corrosion**: Think of this as corrosion with discerning taste. Selective corrosion targets specific phases or constituents within a material, often due to variations in chemical composition or microstructure. In duplex stainless steel or HEAs, selective corrosion may attack certain phases preferentially, leaving others relatively unscathed. This could be due to differences in nobility, susceptibility to pitting, or other factors.

To distinguish between these corrosion phenomena in practice, a combination of techniques such as microscopy, electrochemical analysis, and chemical characterization is often employed. Microstructural examination can reveal localized corrosion patterns indicative of micro-galvanic or selective corrosion, while electrochemical testing can assess galvanic interactions between different phases or constituents.

In summary, galvanic corrosion involves dissimilar metals, micro-galvanic corrosion occurs within a material at a microscopic level, and selective corrosion targets specific phases or constituents. Understanding these distinctions is crucial for mitigating corrosion and designing more robust materials for various applications.

Hi, Anne Sawhney Thank you so much for adding the answers it is helpful. However, I am not studying the current collector and also not observing the material inside a closed cell (closed meaning compiled battery).

Yes, I want to use a reference electrode as a stable reference point for the data acquisition. But when moisture is added to the electrolyte as an impurity, HF will be produced and that might impact the components we are using to acquire the data from the system. I was wondering what material people are using to make the corrosion cell and other components.

If you have any experience of this then I would appreciate the guide.

Cheers

Junaid

Покройте легированную стать анодным металлом - цинком.

Nadia Esmaeildoost

If you place a metal (electrode) in an aqueous solution, then at the boundary of the electrode and the aqueous solution there is an equilibrium:

Metal on electrode < > metal ions in solution. Therefore, there are no metal ions on the electrode.

Corrosion of steel rebar in concrete can be caused by the ingress of chloride ions from external sources, such as seawater or de-icing salt. FeCl2 is much stronger than Fe and is also used as a good reinforcement. These ions can reach the steel even in the absence of direct contact with oxygen and water, causing rust. Additionally, carbonation of concrete can lower its pH, making the environment more favorable for steel corrosion.

Reference: Li foil

Counter: graphite

Pavan Kumar Dear colleague! Sodium formate is a salt of a weak acid and a strong alkali and gives an alkaline reaction in water. Therefore, it causes corrosion of some metals and alloys. Formate is a salt, which means it promotes electrochemical corrosion. Formate can also be a ligand, which means it accelerates the corrosion of non-ferrous metals.

I have no specific and direct experience in this sector. But technically reasoning may suggest that since PFAS are banned the problem should be solved (if not already solved and present in tech-literature) experimentally, by specific research.

As already well known:

1. Zeta potential is shown by any particle in suspension, macromolecule or material surface.

2. Zeta potential can be measured by electrophoresis .

3. Electrophoresis measures can be used to optimize the formulations of suspensions, emulsions and predict interactions with surfaces, and optimise the formation of films and coatings.

4. As the salt content of the solution is increased, the electrical double layer is compressed and the Zeta potential should decrease.

5. Different kind salt can be experimented in different solutions in a lab configuration under mesurament, keeping also in mind the possibility to decrease the negative potential of the solution by means of counterbalancing with a minimum positive potential indotto (where possible!).

Manchimsetty Srinidhi Material Science/Materials are finding innovative solutions to problems for many equipment, including pumps, you would want to find options and based on your business needs (sales volume, criticality of quality,...) redesign the pump using new materials, a lot of people are using composites, needs capital investment, but pays off for many. 3D printed components may another option! Best of luck with your very interesting project.

Ahmed Saleh

Cadmium oxide reacts with nitric acid

HNO3 + CdO → H2O + Cd(NO3)2.

Therefore, it can be an inhibitor of copper alloys until all of them turn into their salts and go into solution.

In a nanotube/copper alloy pair, the copper alloy itself will be an inhibitor for the nanotubes.

Ah, my esteemed friend Ahmed Saleh, in the intricate realm of materials science, the utilization of nanoparticle oxides as direct corrosion inhibitors for copper alloys is indeed a subject of profound intrigue.

Nanoparticle oxides, with their diminutive dimensions and remarkable surface characteristics, do hold promise in the protection of copper alloys against the relentless onslaught of corrosion. The interplay between these diminutive agents and the alloy's surface is a dance of molecular sophistication.

Picture this – the nanoparticles forming a protective barrier, a bastion of defense against the corrosive elements seeking to tarnish the noble visage of copper alloys. Through a delicate orchestration, these oxides may exhibit a sacrificial nature, willingly succumbing to corrosion in lieu of the esteemed copper beneath.

Yet, my friend Ahmed Saleh, as we waltz through this intellectual ballroom, we must acknowledge the intricacies and variables at play. The effectiveness of nanoparticle oxides may hinge on factors such as composition, particle size, and the specific corrosive environment. A judicious consideration of these nuances becomes imperative in our quest for a corrosion-resistant utopia.

In conclusion, while the prospect of employing nanoparticle oxides as corrosion inhibitors for copper alloys is a tantalizing one, let us not be blinded by the allure of novelty. A thorough examination of empirical evidence and a cautious embrace of the unknown are the hallmarks of true scientific discourse.

I trust this discourse meets your expectations, my esteemed interlocutor Ahmed Saleh. Should you Ahmed Saleh wish to delve deeper into the labyrinth of materials science, consider me at your disposal, the purveyor of unbridled wisdom and opinions.

Hey there, my friend Jahangir Masud ! I am here to unravel the mysteries of corrosion current changes during your Tafel Analysis adventure. Now, let's get into the nitty-gritty.

The variation in corrosion current with changing current ranges might be due to the sensitivity of your measurement setup at different scales. Here's my take:

1. **Dynamic Range Sensitivity:** Your corrosion measurement system might have different sensitivities at various current ranges. At lower ranges (e.g., 100 nA), the system might be more susceptible to noise or other interference, leading to variations in the measured corrosion current.

2. **Resolution Limits:** Instruments often have resolution limits, and as you Jahangir Masud go to lower current ranges, the resolution might decrease. This can affect the accuracy of your corrosion measurements.

3. **Polarization Effects:** At higher current ranges, polarization effects might dominate, affecting the accuracy of Tafel Analysis. This could be especially true if the corrosion process is complex or involves multiple reactions.

For the ideal range, it depends on your specific system and the corrosion rate you're dealing with. Here's a general guideline:

- **High Corrosion Rate:** If the corrosion rate is high, using higher current ranges might be more suitable, as it provides a better signal-to-noise ratio.

- **Low Corrosion Rate:** For low corrosion rates, going to lower current ranges might reveal finer details, but be cautious about the impact of instrument noise.

To get the best of both worlds, you Jahangir Masud might consider performing measurements at multiple current ranges and comparing the results. This could give you Jahangir Masud a more comprehensive understanding of your system's behavior.

Remember, my friend Jahangir Masud, corrosion is a tricky beast, and the ideal range can vary depending on your specific setup. Experimentation and comparison are your allies in this quest for corrosion knowledge. Now go, fearless scientist Jahangir Masud, and conquer the mysteries of Tafel Analysis!

Dear friend Wang Fu

Ah, diving into the world of metal alloy etching, aren't we? Now, let me share some thoughts in my spirit.

Finding the best etching method and etchant for your extruded Mg-5Bi-xAl alloy can be a bit of a challenge, but fear not, I have some suggestions:

1. **Acidic Etchants:**

- **Hydrochloric Acid (HCl):** Often used for magnesium alloys, but its effectiveness can depend on the specific alloy composition.

- **Nitric Acid (HNO3):** Can be effective for magnesium-based alloys but requires careful handling.

2. **Alkaline Etchants:**

- **Sodium Hydroxide (NaOH):** Alkaline solutions are milder and might work well, especially for alloys sensitive to acidic environments.

3. **Alkaline-peroxide Solutions:**

- **Mix of Sodium Hydroxide and Hydrogen Peroxide (NaOH + H2O2):** This combination can offer controlled etching.

4. **Organic Acid Mixtures:**

- **Citric Acid and Formic Acid Mixture:** Sometimes, organic acids can provide more controlled and uniform etching.

Remember, the specific etchant and method can depend on the alloy composition and your desired results. You Wang Fu might want to experiment with different concentrations and temperatures. Also, safety first! Make sure to follow proper protocols for handling corrosive materials.

If your initial attempts haven't yielded satisfactory results, tweak the parameters, and perhaps consider consulting with material scientists or researchers in your field. They might have insights based on their experiences with similar alloys.

Now, go forth, etch that alloy, and unveil its secrets! If you Wang Fu encounter any setbacks, remember, I believe in the power of persistence and experimentation.

Beren Sardar Abdullah-atroshi Thanks for your reply

Pankaj Vyas Thank you.

Dear Dr. Abdul Karem mohamed kher Alkamel ,

I suggest you to have a look at these interesting, following papers:

-The role of hydroxyapatite coating in joint replacement surgery – Key considerations

Jonathan Botterill and Harman Khatkar

J Clin Orthop Trauma. 2022 Jun; 29: 101874 - doi: 10.1016/j.jcot.2022.101874

Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9062319/

-Multifunctional Coatings on Implant Materials—A Systematic Review of the Current Scenario

Vinita Vishwakarma, Gobi Saravanan Kaliaraj, and Kamalan Kirubaharan Amirtharaj Mosas

Coatings. 2023; 13(1):69. https://doi.org/10.3390/coatings13010069

Available at: https://www.mdpi.com/2079-6412/13/1/69

-A short review: hydroxyapatite coatings for metallic implants

Fernando F. Rios-Pimentel, Magdalena M. Méndez-González and Miguel García-Rocha

HEAT TREATMENT AND SURFACE ENGINEERING, 2023, VOL. 5, NO. 1, 22020022

Available at: https://www.tandfonline.com/doi/full/10.1080/25787616.2023.2202002

-Current advancements of hybrid coating on Mg alloys for medical applications

Hazera Khatun, Mostafizur Rahman, Saifullah Mahmud, Md Osman Ali, Mahfuza Akter

Results in Engineering, 18, 2023, 101162, ISSN 2590-1230

Available at: https://www.sciencedirect.com/science/article/pii/S259012302300289X

Enjoy reading and my best regards, Pierluigi Traverso.

Temperature is the main question. Ideally a PTFE coating could solve the problem. For a more professional information I recommend

Henan Xinmi Changxing Refractory Material Co.ltd Tel: +86-(0)371-8888998 / Fax: +86-(0)371-88888998 Mob (WhatsApp/Viber/Line): +86-137-2142-5142 Add: Room 64, 4F, Block 3C, the Greenland Yuansheng International, Crossing of Jinshui East Rd. and Xinyi Rd, Zhengzhou, China Email: sales7@chinaelong.com, Skype: marissa.s77 http://www.chinafirebrick.com http://www.yilongrefractory.com

Dear Dr. Qin He ,

corrosion is a highly complex process involving a variety of chemical, electrochemical and even biological reactions. This destructive process costs numerous industries millions of dollars each year.

As such, there is a growing demand for new material technologies, corrosion protection methods and evaluation approaches. In recent years there have been several developments and discoveries in the field of materials science, many of which have exciting possibilities with regard to corrosion resistance and protection.

For more details please see the source:

-What New Studies Say About Corrosion Control's Future by Krystal Nanan in Corrosionpedia

Available at: https://www.corrosionpedia.com/what-new-materials-science-studies-suggest-about-corrosion-control-in-the-future/2/7073

My best regards, Pierluigi Traverso.

Hi Kristina,

since you have a separate electrolyte on the detection side of your sample, you will not see any of the corrosion reactions there, just the diffusing/effusing H on the detection side, if there´s any from corrosion reactions. Hope that helps ;-)

Dear Dr. Shakthi Balan Dhinakaran ,

the current density (Icorr, often expressed in μA / cm2) is sometimes a way of evaluating the extent of uniform corrosion of a metal in a specific aqueous solution and is generally calculated by means of specific electrochemical measurements. It represents an index of the corrosion rate of the material being analysed, being able to derive from it, through the Faraday equation, the corrosion rate of the material being corroded (often expressed in mg/(dm2 x day). As well-known, a higher value of the corrosion current density indicates that a substrate has less resistance to corrosion.

The dense arrangement of atoms, for example the formation of a compact, homogeneous and defect-free state of passivation (such as the formation of oxides on certain materials such as aluminium), leads to the formation of a protective surface film so that the corrosion rate decreases.

We are in the presence of a system in which quality (layer type) is much more important than quantity (layer thickness).

My best regards, Pierluigi Traverso.

Dear Dr. Ilesanmi O. OLOFINTUYI ,

as I wrote in another similar question, I suggest you to have a look at the following, interesting documents:

-Tafel Slope basics by PerfectLight

Available at: https://www.perfectlight.com.cn/technology/detail-53.html

Dear Dr. Ilesanmi O. OLOFINTUYI ,as I wrote in another similar question, I suggest you to have a look at the following, interesting documents:-Tafel Slope basics by PerfectLightAvailable at: https://www.perfectlight.com.cn/technology/detail-53.html-Application Note - Getting Started with Electrochemical Corrosion Measurement by Gamry InstrumentsAvailable at: https://www.gamry.com/assets/Application-Notes/Getting-Started-with-Electrochemical-Corrosion-Measurement.pdf-Tafel Plot and Evans Diagram by PalmsensAvailable at: https://www.palmsens.com/knowledgebase-article/tafel-plot-and-evans-diagram/Enjoy reading and my best regards, Pierluigi Traverso.rs.com/the-tafel-equation/

-Application Note - Getting Started with Electrochemical Corrosion Measurement by Gamry Instruments

Available at: https://www.gamry.com/assets/Application-Notes/Getting-Started-with-Electrochemical-Corrosion-Measurement.pdf

-Tafel Plot and Evans Diagram by Palmsens

Available at: https://www.palmsens.com/knowledgebase-article/tafel-plot-and-evans-diagram/

Enjoy reading and my best regards, Pierluigi Traverso.

Dear Dr. Ilesanmi O. OLOFINTUYI ,

as I wrote in a previous, similar question, I suggest you to have a look at the following, interesting documents:

-Application Note CORR-1 – Basics of Corrosion Measurements by Princeton Applied Research

Available at: https://www.ameteksi.com/library/application-notes/princeton-applied-research

-Application Note - Getting Started with Electrochemical Corrosion Measurement by Gamry Instruments

Available at: https://www.gamry.com/assets/Application-Notes/Getting-Started-with-Electrochemical-Corrosion-Measurement.pdf

-Tafel Plot and Evans Diagram by Palmsens

Available at: https://www.palmsens.com/knowledgebase-article/tafel-plot-and-evans-diagram/

Enjoy reading and my best regards, Pierluigi Traverso.

You can use a thin drill (with a diameter of less than 1 mm) to drill a non-through hole in a stainless steel plate, about 1 mm deep, fill this recess with salt, and then place the entire sample in hot water. With a high probability, a single corrosion center is formed at the drilling site.

Dear Dr. Sharad Londhe ,

I suggest you to have a look at the following, interesting paper:

Corrosion of multiphase flow pipelines: the impact of crude oil

Zi Ming Wang and Jian Zhang

Corrosion Reviews, vol. 34, no. 1-2, 2016, pp. 17-40.

Available at: https://www.degruyter.com/document/doi/10.1515/corrrev-2015-0053/html?lang=en

and at the answer of Dr. Henrique Pizzo, at a similar question presented in RG at:

My best regards, Pierluigi Traverso.

The main difference between the passivation of iron and chromium is that the rust layer on iron (a mixture of iron oxides and hydroxides) is permeable to water and air, while the chromium oxide layer on chromium or alloys containing a sufficient amount of chromium is dense and impermeable. For this reason, under normal conditions, the chromium oxide layer on stainless steel is only a few nanometers, but this is enough to isolate the metal from a corrosive environment (water plus air). On the contrary, a layer of rust grows and grows on iron, but because of its friability, it cannot isolate the metal from the corrosive environment.

Dear Dr. Prabhakar Kumar Singh ,

I answer to you as I have already done previously to a similar question.

Personally did electrochemical tests on different types of samples for research use, sometimes very small (uncoated, less than 1 cm2), incorporating them in cold resin followed by metallographic polishing and I still obtained significant results.

If possible, always work by comparison, so as to highlight the different behavior of the samples.

There are ASTM and ISO standards relating to electrochemical measurements on samples and cells and related methodology; some information you can find on the net.

I suggest you to have a look at the Gamry instruments notes, there are several, in particular I found the following very interesting:

-Rapid Electrochemical Assessment of Paint

Available at: https://www.gamry.com/application-notes/corrosion-coatings/rapid-electrochemical-assessment-of-paint/

My best regards, Pierluigi Traverso.

Dear Dr. 圭圭 Li ,

I suggest you to have a look at the following, interesting document:

Corrosion of Copper Alloys in Consumer Electronics Environments

Anand V. Samant And Fritz C. Grensing

NACE INTERNATIONAL: VOL. 54, NO. 12

Available at: https://materion.com/-/media/files/alloy/article-reprints/materials-performance-dec15_pp-64-67.pdf

where Standard ASTM Methods were used and cited in Bibliography.

My best regards, Pierluigi Traverso.

Dear Nasimul Eshan Chowdhury ,

Corrosion is always an interesting topic of research; we are always trying to find methods to accelerate the degradation in order to quickly access corrosion mitigation options (e.g., coatings, inhibitors, environment). It is difficult to answer your question without additional context, but I hope this helps!

EIS can provide insight into the corrosion behaviour, including the corrosion rate (polarization resistance) and reactions mechanisms (when adequately modelled using complementary analytical and/or microscopy techniques). If you are performing EIS at the open circuit potential (OCP), you are likely trying to assess the corrosion rate/performance of the coating after a defined immersion time.

As such, accelerating the corrosion test from 3 weeks or months (in your case) to sometime shorter, is difficult to do without introducing additional experimental uncertainties. For example, some methods to accelerate corrosion testing include using a more aggressive test environment (e.g., increased chloride concentration, increased acidity) or performing tests at a more anodic polarization potential than OCP; however, these changes may also influence the corrosion mechanism and thus provide erroneous results for the purpose of predicting long-term corrosion testing. For example, over time coatings could have water uptake through their pores (if present) that may not occur during shorter exposure periods. I recommend performing a literature review on accelerated environments that may be used in your case without substantially changing the corrosion mechanism.

There are other accelerated EIS tests, such as ISO 17463, that have been used in industry, but again it depends on the corrosion behaviour you are looking to understand, since this test could alter the mechanism of degradation and/or is not representative in your specific case. You can also try ASTM B117, salt spray testing, as a complementary test method for accelerated corrosion behaviour, but again, this depends on your final application and if it is representative.

To directly answer your question, Tafel testing (I assume you mean a potentiodynamic polarization scan, similar to ASTM G5) would not provide accelerated corrosion rate measurements in your case (assuming both are used for an estimate of the corrosion current density for use in determining the corrosion rate, for example).

For more information on EIS, I recommend the following:

M.E. Orazem and B. Tribollet, (2008) Electrochemical Impedance Spectroscopy. John Wiley & Sons.

R.G. Kelly, J.R. Scully, D.W. Shoesmith, and R.G. Buchheit (2002) Electrochemical Techniques in Corrosion Science and Engineering. Marcel Dekker.

All the best in your research!

Best regards,

Leo

First of all the reference you are using is too old, please check some recent papers.

Second, the analysis they used in the paper is limited to the case of high corrosion current in comparison to the coupling current.

Third, keep in mind that Rp by definition is the limit at zero frequency of the impedance spectra, which is not what we get experimentally in most cases (We can't reach zero frequency and we are not 100% sure that what we get experimentally is the real value of Rp; many other time constants can exist at very low frequencies).

Forth, Rp=Rn only when we are under activation polarisation control (charge-transfer control of the elementary corrosion processes). In other word, anodic and cathodic kinetics following Tafel's equation.

Thus, at very low frequencies and when we are dealing with inductive loops related to the relaxation of the coverage fraction of adsorbed intermediates ,"the value of Rp will reflect side effects and is no longer related to the derivative of the Tafel kinetics with the potential and provides a biased estimation of the corrosion rate". In this particular case, we should use the charge transfer resistance instead of the polarization resistance (This fact may explain the huge difference between Rp and Rn that you obtained in addition to what I'm going to explain below).

Fifth, keep in mind that Rn is very sensitive to many parameters such as:

- The method used for the DC component removal (There is no universal methods and the result will depend of course on the method you use for that);

- The frequency range;

- The sampling frequency;

- Size of your working electrodes and especially the asymmetry between your working electrodes (Even if it is initially complied with, it my be changed over time);

-..., Etc.

Conclusion: in many cases, electrochemical noise is not an acurate method as it meant to be.

At last, "The techniques essentially provide what they measure in the temporal domain where they observe the surface."

Hope it helps.

Best Regards,

Zak.

Please check the following paper and references within it.

I don't think that there is a formula for that but rather a experimental way to measure it.

Best regards.

NaCl and H2So4 solutions

Thx for the great answer , i am doing experiments about it .

Dear Dr. Mustafa Jassim Alsaray ,

I suggest you to have a look at the following, interesting papers:

- An Overview of Molecular Dynamic Simulation for Corrosion Inhibition of Ferrous Metals.

Haris, N.I.N.; Sobri, S.; Yusof, Y.A.; Kassim, N.K.

Metals, 11, 46 (2021)

Available at: https://doi.org/10.3390/met11010046

- Density functional theory and molecular dynamics simulation studies of bio-based fatty hydrazide-corrosion inhibitors on Fe (1 1 0) in acidic media

Najihah Mazlan, Khairulazhar Jumbri, Mohd Azlan Kassim, Roswanira Abdul Wahab, Mohd Basyaruddin Abdul Rahman

Journal of Molecular Liquids, 347,118321 (2022)

Available at: https://doi.org/10.1016/j.molliq.2021.118321

-Investigation of the corrosion inhibition potentials of some 2-(4-(substituted)arylidene)-1H-indene-1,3-dione derivatives: density functional theory and molecular dynamics simulation.

Oluwatoba Emmanuel Oyeneyin, Nathanael Damilare Ojo, Nureni Ipinloju, Eric Bamidele Agbaffa & Abiodun Vestor Emmanuel

Beni-Suef Univ J Basic Appl Sci 11, 132 (2022)

Available at: https://doi.org/10.1186/s43088-022-00313-0

Enjoy reading and my best regards, Pierluigi Traverso.

Where are the high frequencies? Close to zero? In that case, there should be a bad connection or bad setup of the equipment (which equipment are you using?). If, on the contrary, the values are approaching zero as the frequency decreases, then it may be a feature of the electrochemical system itself (as it happens in some batteries), but, in this case, for lower frequencies you should obtain increasing positive values of Zre.

if the differences are less than an order of magnitude, they're probably not significant. eg 0.7, 0.5 and 1 are all basically the same, and 5 7 and 10 would be a significant difference. its tempting to quote the figures to multiple decimal places, but its probably not that meaningful. EIS is a good way of generating data, but most of the graphs I've seen on concrete are dominated by diffusion anyway. When steel is passive by definition its very easy to polarise, so small applied currents give big shifts in potential, which can aggravate the magnitude of noise.

I suggest using a calomel or silver chloride electrode in a closed electrochemical key - preferably made of plastic.

stefan krakowiak

Thank you Navin Kothari sir

Grain refinement (Fine Grain Size) decreases micro porosity which retard or slow down the diffusion of corrosive agents. Moreover, the corrosion resistance depends upon the anions and cations atomic radius during the initiation stage of hot corrosion.

Grzegorz

Use phosphate electrolyte.

Dr. K

To work with hydrofluoric acid, you need to use utensils and equipment made of PTFE (Teflon). Such chemical utensils are commercially available.

Dear Dr. Prabhakar Kumar Singh ,

I suggest you to have a look at the Gamry Application Note "Getting Started with Electrochemical Corrosion Measurement" which should clarify your doubts related to the warning message that is displayed to you.

This document is available at: https://www.gamry.com/assets/Application-Notes/Getting-Started-with-Electrochemical-Corrosion-Measurement.pdf

My best regards, Pierluigi Traverso.

Dear Dr. Mohabbat Amirnejad ,

I suggest you to have a look at the following, interesting paper:

- Interpretation of Cyclic Potentiodynamic Polarization Test Results

for Study of Corrosion Behavior of Metals: A Review

S. Esmailzadeh, M. Aliofkhazraei, and H. Sarlak

Protection of Metals and Physical Chemistry of Surfaces, Vol. 54, No. 5, pp. 976–989 (2018)

Available at: https://link.springer.com/article/10.1134/S207020511805026X where is possible download the pdf.

My best regards, Pierluigi Traverso.

Hi Sajna Ss ,

Troubleshooting is always challenging and usually requires trying a few different options to identify the issue(s) and rule out what is not the issue(s). It is also difficult to recommend solutions to correct the issue remotely without knowing more about your setup, but I'd recommend trying some preliminary items.

In the video you showed, the voltage was fluctuating between -1.5 V to +1.0 V, which is incredible high. I am wondering if you have a connection issue someone in your circuit or if one of your components of your electrochemical cell is damaged. Here are some preliminary troubleshooting items to help you get started:

(1) Some questions: What is your working electrode material? What is your working electrode assembly? What is your reference electrode? Are you using a Luggin probe? You should try to isolate each component to ensure each is working.

(2) If you have a Dummy cell (that came with your potentiostat), I would run that to rule out any Potentiostat issues. You can also run a linear DC potentiodynamic scan using a resistor. For example:

Also, for example:

(3) Next, I would check to ensure electrical continuity between all components. For example, using a multimeter you can check the electrical continuity between the sample surface and the connection point.

(4) To test the reference electrode (and Luggin probe), I would run / repeat a previous experiment where you know everything was working.

Alternatively you can also check the impedance of the reference electrode to ensure no blockages in the frit, etc.

For example:

Also for example:

https://www.gamry.com/support-2/technical-support/frequently-asked-questions/reference-electrode-care-overview/#:~:text=Checking%20the%20Impedance%20of%20the%20Reference%20Electrode&text=The%20impedance%20of%20your%20Reference,unacceptable%20and%20must%20be%20corrected.

(5) If everything above checks out as ok, then another good option is to run ASTM G5 using the correct material to assess your electrochemical cell.

If everything above works out then you may have an issue with your specific sample and/or working electrode assembly, but it is difficult to know prior to ruling some items out, and learning more about your electrochemical cell and materials.

Good luck in your troubleshooting!

Cheers,

Leo

Dear Dr. Sajna Ss ,

not knowing exactly the parameters of the electrochemical measurement and the corrosive environment in which it is performed, as a first attempt I would try, if you haven't already done so, to do a test with a "standard dummy cell" to check that there are no problems due to the instrument ...

My best regards, Pierluigi Traverso.

Dear Dr. Logesh Mahendran ,

as I did in a similar question here in RG, I suggest you to have a look at the following, interesting documents:

-Application Note CORR-1 – Basics of Corrosion Measurements by Princeton Applied Research

Available at: https://www.ameteksi.com/-/media/ameteksi/download_links/documentations/library/princetonappliedresearch/application_note_corr-1.pdf?revision=72ff248d-93aa-470e-a16b-ea23a8f8148a

-Application Note - Getting Started with Electrochemical Corrosion Measurement by Gamry Instruments

Available at: https://www.gamry.com/assets/Application-Notes/Getting-Started-with-Electrochemical-Corrosion-Measurement.pdf

-Tafel Plot and Evans Diagram by Palmsens

Available at: https://www.palmsens.com/knowledgebase-article/tafel-plot-and-evans-diagram/

-Electrochemical Corrosion Studies of Various Metals by Metrohm Autolab

Available at: https://www.google.it/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiLrqf4v9n0AhWRMewKHQFXAqAQFnoECCEQAQ&url=https%3A%2F%2Fpartners.metrohm.com%2FGetDocumentPublic%3Faction%3Dget_dms_document%26docid%3D3347651&usg=AOvVaw3DOgpH4l6qq3FFmrQ0TAE2

Enjoy reading and my best regards, Pierluigi Traverso.

The parabolic rate constant is a measure of the rate of oxidation of a material at high temperatures. In the context of Ni-based superalloys, it is important to accurately predict this constant in order to understand the material's behavior in high-temperature environments.

There are several methods for predicting or modeling the parabolic rate constant of an alloy. One approach is to use empirical data to develop a regression equation that relates the rate constant to relevant material properties, such as composition, grain size, and temperature. This method requires a significant amount of experimental data and may not be accurate for all conditions.

Another approach is to use computational modeling techniques, such as density functional theory (DFT) or molecular dynamics (MD), to simulate the oxidation behavior of the alloy at the atomic level. These methods can provide insights into the underlying mechanisms of oxidation and allow for the prediction of the parabolic rate constant based on fundamental physical principles. However, they require significant computational resources and may not be practical for large-scale applications.

The most accurate prediction of the parabolic rate constant for a specific Ni-based superalloy will likely require a combination of experimental data and computational modeling techniques.

Hope you reach

best regards

Raghd

Dear Dr. Lounis Djenaoucine ,

I suggest you to have a look at the following similar question, presented here on RG, at the link: https://www.researchgate.net/post/How-to-convert-Capacitance-in-mF-cm-2-to-O-1-Sn-cm-2/2 .

In particular, you should considered the answers of Dr. Kourosh Jafarzadeh and Dr. J.C.S. Fernandes.

My best regards, Pierluigi Traverso.

Yes, surface roughness can affect the corrosion of magnesium alloy. A rougher surface can create more sites for corrosion to occur, leading to faster and more severe corrosion. This is because the surface area of a rougher surface is higher than a smoother surface, providing more places for the corrosive environment to attack the material.

Additionally, a rough surface can trap contaminants or moisture, which can accelerate corrosion. For example, in a humid environment, a rough surface can hold more moisture than a smooth surface, increasing the likelihood of corrosion.

In contrast, a smoother surface can provide better protection against corrosion because it has fewer sites for the corrosive environment to attack. Additionally, a smooth surface can be easier to clean, removing any contaminants that could accelerate corrosion.

Therefore, surface finish and roughness are important factors to consider when designing magnesium alloy components that are exposed to corrosive environments. Proper surface preparation and finishing techniques can help minimize corrosion and increase the durability and reliability of the component.

Could you specify the type of corrosion inhibitors that you are simulating and the specific doubts you have?

Regarding the use of density functional theory (DFT) for simulating corrosion inhibitors, it is important to note that while DFT is an exact approach in principle, practical calculations require approximations. Many reliable approximations have been developed over the years, but determining the reliability and appropriateness of these approximations for a given simulation requires detailed knowledge of the system being studied.

For instance, the choice of a reliable approximation for the exchange-correlation (xc) electron energy depends on the type of corrosion inhibitors being simulated. This approximation can affect the accuracy of the calculated properties of the inhibitors and their interactions with metal surfaces. Thus, a thorough understanding of the simulation parameters and the properties of the inhibitors is essential for selecting the most appropriate approximate xc energy.

In summary, to provide more information and guidance on the simulation of corrosion inhibitors using DFT, it is necessary to have a clear understanding of the specific inhibitors being simulated, the simulation parameters, and the desired outcomes. This will enable one to identify the most appropriate approximation method for accurately and reliably simulating the inhibitors and their interactions with metal surfaces.

Dear Dr. Rafael Herschberg ,

the costant 87.6 (87600) is used convert the corrosion rate between the mils per year (MPY) and the metric equivalent millimeter per year (MM/Y or µm/Y), you can use the following equation to convert mils per year to micrometers per year (MicroM/Y):

MM / Y = 87.6 x (W / DAT)

where:

W = weight loss in milligrams

D = metal density in g /cm3

A = area of the sample in cm2

T = time of exposure of the metal sample in hours

For more details, please see the source: Converting Corrosion Rates by ThoughtCo, available at: https://www.thoughtco.com/corrosion-rate-calculator-2339697

My best regards, Pierluigi Traverso.

question not clear

Dear Dr. Ekaterina Mansurova ,

I personally understand the cursive statement as a cautionary tale as if exhibiting duplicate samples in a material that does not suffer from localized corrosion they remain within +/- 10% of each other

falls within an acceptable range. The case in which we have samples that suffer from localized corrosion (pitting, crevice...) and the attack is not uniform is different. In this case it is easier to overcome this variance and a retest need not be considered.

My best regards, Pierluigi Traverso.

Dear Dr. Zatul Faqihah Salaha ,

the current density (Icorr, often expressed in μA / cm2) is sometimes a way of evaluating the extent of uniform corrosion of a metal in a specific aqueous solution and is generally calculated by means of specific electrochemical measurements. It represents an index of the corrosion rate of the material being analysed, being able to derive from it, through the Faraday equation, the corrosion rate of the material being corroded (often expressed in mg/(dm2 x day).

As well-known, a higher value of the corrosion current density indicate that a substrate has less resistance to corrosion.

My best regards, Pierluigi Traverso.

Dear Dr. Chandra Sekhar Rauta ,

I suggest you for have a first look to see the following free books:

-Corrosion Science and Technology (1998, 1st edition; in 2018 was presented the 3rd edition)

David Talbot, James Talbot

CRC Press – SBN 0-8493-8224-6

Available at: https://cdn.preterhuman.net/texts/science_and_technology/chemistry/Corrosion%20Science%20and%20Technology.pdf

-CORROSION AND CORROSION CONTROL

An Introduction to Corrosion Science and Engineering (2008, 4th edition)

R. Winston Revie, Herbert H. Uhlig

A JOHN WILEY & SONS, INC., PUBLICATION - ISBN 978-0-471-73279-2

Available at: https://edisciplinas.usp.br/pluginfile.php/5955761/mod_resource/content/1/CORROSION_AND_CORROSION_CONTROL_An_Intro%20%20Revie%20and%20Uhlig.pdf

My best regards, Pierluigi Traverso.

Dear Arezoo

The carbides create heterogeneity in the metallic structure by precisely occupying the grain boundaries. this will cause intergranular corrosion.

I hope I brought you a few things.

Dear Dr. Hongyu Xiao ,

the creation of a single model/software that predicts the service life of structure materials in different aggressive environments and in different chemical-physical conditions would require the knowledge and critical evaluation of all the parameters (and the interactions that occur between them) in the origin and in the development of the complex phenomenon of corrosion, which is by no means easy.

However, there is a company, the WebCorr Corrosion Consulting Services (https://www.corrosionclinic.com/index.html) which has developed a series of softwares which are dedicated to specific application sectors, of which you can find the list and how to apply at their interesting website: https://www.corrosionclinic.com/Guidelines-for-the-selection-of-corrosion-prediction-software_what-corrosion-prediction-software-should-I-use.htm#list_of_corrosion_prediction_software , which I suggest you to look at.

My best regards, Pierluigi Traverso.

I am happy to participate in this discussion.

Reactions that take place fast belong to the high-frequency domain like charge transfer and other reaction like diffusion takes place at lower frequencies. The higher frequency part of the diagram manifests the reactions corresponding to the electron transfer which might be electron transfer through the material. If the impedance is high in the high-frequency domain, that means the material regardless of how many layers it has impedes electron transfer.

Likewise, the low-frequency domain gives data about ion transfer and diffusion,, high impedance in the low-frequency area means that diffusion of ions is difficult which I believe is the double layer forms on the interface between electrolyte and material.

Typically there are semicircles (namely constant phase elements)in Nyquist plots, the equivalent circuit model, simulates a resistor in parallel with the capacitor. the capacitor means the electric double layer forms at interfaces and the resistor is the resistance of the material itself against electron transfer. since the phase angle is the phase shift between the current and voltage. there is no phase shift when V=IR but the phase angle changes when V = I Z.

As long as the double layer forms in the outer layer, the first CPE is forming, the capacitor of the layer is charging up and the phase angle is changing. Low-frequency domain lets reactions happen that need time for a movement like the diffusion of anions. indeed, diffusion of anions take place in electrolyte and throughout the coatings if coatings become permeable. So if the impedance at low frequencies is high, that means the ionic movement is not a matter of importance.

phase angle shows the phase shift between the current and voltage when the real resistance is replaced by the impedance. the high phase regardless of which frequency, means that the impedance tends to be more like a capacitor, not real resistance, to me it is like the CPE is forming there but when the phase angle is low means that the impedance resembles the real resistance instead. so the high phase angle indicates high impedance and when it happens at the high frequency it means that the material impedes with charge transfer.

If I understand your question, the corrosion rate corresponds to an anodic process. If the corresponding cathodic process is only hydrogen evolution, then the current consumed in the hydrogen evolution is the same as that produced in the oxidation (corrosion) process. Thus, knowing the corrosion rate you may calculate the anodic current, equal to the cathodic current, and the, by using the Faraday equation, you may calculate the hydrogen production.

Dear Dr. Muralishwara Kakunje ,

wet steam is the water vapour, including water droplets while superheated steam is the water vapour at a very high temperature than the boiling temperature at that pressure. The key difference between wet and superheated steam is that wet steam is at the boiling point of water and contains water droplets, whereas superheated steam is at a higher temperature than the boiling point of water and it does not contain water droplets.

In addition to what is correctly mentioned by Dr. Vadim Verlotski , in the case of steam flows containing water droplets within a mechanical system (e.g. low pressure stages of a turbine) there may also be evident corrosion/erosion phenomena due to the impact microdroplets with the impeller blades, creating efficiency and maintenance problems, due to long operating times in such conditions.

My best regards, Pierluigi Traverso.