Galvanic Corrosion | Forms of Corrosion

Galvanic Corrosion is an accelerated form of corrosion that occurs when two dissimilar metals are in an electrical contact. The more noble metal drives the corrosion of the active metal and this can be a very fast process. For example if an aluminum frame is connected with steel bolts then aluminum rapidly corrodes and after a few months the whole construction may collapse. So how to prevent galvanic corrosion? First, one should connect only those materials that have a similar electrochemical activity. Second, dielectric corrosion resistant coatings should be applied on the metal parts so that the electrochemical processes cannot take place.
This free educational video about galvanic corrosion was done in collaboration with the Institute of Physics, University of Tartu.
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[@CaptainCorrosion]

You can now simulate galvanic corrosion with our new online tool: captaincorrosion.com/galvanic-corrosion-simulator/

[@SmartFill]

can any body help me i need a screw who didn't rust nor collect salt in water plus pass electricity which metal i use help me plz.. i use normal metal screws it rusted plus collect salts under water in few days they didn't abe to pass electricity due rust and white salt layer gether on it

[@katatonos]

Excellent explanation. Something that should be mentioned too, is how to eliminate galvanic corrosion, but also keep an electrical connection. You walked up to the door saying to use an insulator that eliminates the electrical connection. If you have two metals that are two metal groups apart from each other, you can use a third different metal that is in the middle metal group (i.e. aluminum frame and a stainless steel screw, you can use cadmium as a buffer metal). This keeps an electrical connection, but reduces the chance of galvanic corrosion. This is useful is you are using your chassis frame as a grounding path to earth ground.

[@JordanHole]

On my way ton exam, brilliant video to watch prior

[@CaptainCorrosion]

Thanks!

[@RedGloveFan]

Fantastic Video...I actually learned more about corrosion. Thank you!

[@CaptainCorrosion]

And thank you for watching!

[@SaurabhSinghbuta]

Thanks for explaining in this much simple way.

[@CaptainCorrosion]

Thanks a lot for watching!

[@KLink9292]

Thanks man. Exactly what I wanted to know. Great video

[@martingarcia-vc2ws]

Great video!

[@johnsampathkumar]

Thanks for explaining with examples

[@AmanAli-jo5zt]

Thnx sir u might be the best one who made the video on this in this platform

[@CaptainCorrosion]

Thanks!

[@raisharayhan1483]

done a great job. made it clear and easy to understand . thanks

[@CaptainCorrosion]

You are welcome!

[@mouradaissat1235]

Thanks Maido for your prompt reply.

[@nomipakistanli]

i like quick compact and to te point videosss.

[@hibasmadi2127]

thank you

[@robertheidersbach588]

Well done, great animations, great explanation. As author of Metallurgy and Corrosion Control in Oil and Gas Production, I give this video a thumbs up!

[@CaptainCorrosion]

Thank you! Our team is planning to make a video about corrosion of carbon steel in oil and gas industries as well at some point in the future.

[@moosaalmarzouq4994]

Thanks! this was useful.

[@EverydayWorkshop]

Great video, very informative. Thank you. 👍🙂

[@CaptainCorrosion]

Thanks for watching!

[@inspectioncorrosion]

Thanks for the sharing

[@xTheEAKx]

great video, thank you good luck on your exams people

[@sxndrxcore]

Super useful! Thank you very much

[@CaptainCorrosion]

And thank you for watching!

[@itsallaboutthecocktail]

Thank you

[@dig1035]

Thank you!

[@ThomasChaote]

thanks for this!

[@CaptainCorrosion]

And thank you for watching!

[@konde020202]

thanks captain

[@mba2ceo]

genius !!! Thank U

[@chrispcriddercridder6397]

thank you ... nice vid ..

[@eddybash1342]

4:40 Hi Captain Corrosion, The dielectric union is used between a hot water boiler made of Iron and a water pipe made of copper. I 'd like to know what you think about the ground connection (GND) between the water boiler and the pipes. The building code requires the ground connection of all water pipes made of metal. I think the electrons close the electrical circuit, so the corrosion is active. Many thanks Captain Corrosion !

[@CaptainCorrosion]

A crucial part of galvanic corrosion is also the electrical resistance between the connected parts. So if you have to ground all the metal components but still want to mitigate galvanic corrosion, then try to increase the electrical resistance between the two metal parts as much as possible. use a multimeter to play with the resistance.

[@MacMetal215]

Hello! Great video! I am a fabricator and have been experimenting with aluminum electrochemistry to rapidly produce an astheticly organic looking surface on huge sheets aprox. 3ft by 10ft by 3/4" thick. I have been making samples on 5"x10"x1/4" 6061AL so far my consistant technique has produced the desired texture but it involves much attention and agitation to the solution and surfaces. I have simply applied sodium chloride on the negatively charged aluminum plate and rested the positively charged plate directly on top, both submerged in tap water. I run aprox. 17amps for 20min, then remove and agitate the surface on both +/- plates. I add a little more sodium chloride to the (-) charged suface and rest the opposite plate back on it for another 20min. I then remove the (+) plate and scrub with a wire brush to clean all the biproduct off which I assume to be sodium hydroxide?? not sure since the metal it forms on is aluminum. I am looking to get an extremely aged surface. I can send photos and videos to show you my technique. this is a huge project for work and would mean a great deal to aquire any information from you to help me simplify my technique. not sure if I'm doing anything wrong.

[@MacMetal215]

+Maido Merisalu thank you for the quick reply! Definitely a lot of useful informatoin for future projects! I would like to send you a few photos of my results. Really would like to hear your thoughts after seeing my samples as well.

[@fewcommentsonnews.4842]

THANK YOU FOR _ His aid in order to allow me understand better these harsh questions about corrosions, Which are setting in Steel pipes or other worthy maquinaries. Certainlly, It has brought up for unsperiencied professional uncontable damages along. In conclusion , It Could be avoiding due to this New expertise acquirred since of now for ever for us from you ( Thank you ).

[@bhekakunene2231]

Thank you Man

[@CaptainCorrosion]

And thank you for watching!

[@bankholiday9222]

Tq sir helped me a lot❤️❤️❤️

[@dcsschoolworkashermichael4318]

hi Maido! In impressed current protection of steel is the cathodic reaction similar? Because the steel is already reduced then the extra electrons reduce oxygen? Please help!

[@fatimamohammed3418]

Thanks

[@CarlosGarcia-zy6yg]

Excellent material. Very well and easily explained. Congratulations. Could you prepare some equivalent material with other type of corrosion such as Pitting Corrosion, Crevice Corrosion, etc.?.

[@CaptainCorrosion]

Heya! These topics are already in our to-do list but we'd also like to update the galvanic corrosion video as there are some aspects we missed and/or could explain better.

[@IM024]

nice video :) thank you for the insight i needed ^^

[@IM024]

thumbs up !!! ^^

[@CaptainCorrosion]

And thank you for watching! We will be making more corrosion related videos in the future as well.

[@IM024]

ok i will subscribe then so i can follow the procedure .. i like informative video`s ^^

[@robertstancer4469]

A view from the UK and a retired electrical engineer and fully understand the principle of electro-plating. Could you be the person that finally explains to me why it is called a sacrificial "Anode" and not a cathode as the reason it gets "eaten" is because it is being stripped of electrons. If it's being stripped of its electrons then surely it is a cathode? Conventional current flow is from positive - anode to cathode - negative. This is a "customer" explanation of an electrical circuit. But we engineers know that it is electron flow from cathode to anode that is the basis of a current flow and that is negatively charged electrons from the cathode are being attracted to the anode which is electron deficient and wants to stabilise. As you also know when charging a battery we, in effect, reverse the polarities and send the electrons back to the cathode and make the battery unstable again - or what the customer calls "charged". For those that don't know, a flat battery is when the anode and cathode have their own required number of electrons for their atoms. What am i missing please?

[@judolife6722]

I wish my teacher explain me the you do,thank you ,I got it now

[@ramzinasereddin8840]

Helpful👍

[@user-fu9bk3po4s]

I like the introduction background music. It was used in a game called R.U.S.E.

[@CaptainCorrosion]

It is possible because we use stock music and sound effects in our videos.

[@ammaralmihyawi3538]

The KZbin channel DIY Perks made an interesting Video about a playstation 5 slim but someone mentioned galvanic corrosion. Can you elaborate on that?

[@santoshkumardas2002]

nice chapter..... tq sir ...

[@CaptainCorrosion]

Thanks for watching!

[@juancarloscespedes9351]

thank you :D good video :D

[@CaptainCorrosion]

Thanks!

[@robbytandiono3376]

i have tagged two picture of used zinc anode on your facebook...thanks

[@GatorGillLLCSteveandTresaShort]

A lot of boat owners are doing their own boat hull maintenance and cleaning. We at Gator Gill help provide safe and cost effective ways to help boat owners stay under water and complete their tasks. Knowing wither to use a zinc or magnesium based anode is also key too a properly maintained vessel. Your video is very informative thank you

[@duydangdroid]

very good

[@CaptainCorrosion]

Thanks!

[@podtraining741]

HI Great presentation. one of the best I have seen. Would you mind if I used this in a training course presentations about steel towers thanks in anticipation gareth

[@CaptainCorrosion]

You are only allowed to link to the original video. We hold the copyright for the video and keep it available only on the KZbin platform on our official channel.

[@shreyasubale3400]

Please add subtitles as the voice is not clear. ! I had to rewind it many times ! Please do the following

[@ericohman]

When you say active, do you mean high electronegativity value? If I combine stainless steel bolts and Zinc, I believe stainless steel have higher electronegativity, which of the two metals would corrode and get damaged?

[@CaptainCorrosion]

Hello and thank you for the question. If you want to know if the two materials should be combined together then you should look at the galvanic series in sea water, not the electronegativity value. Passive metals such as Gold and Platinum do have higher electronegativity value than active metals such as Zinc and Aluminium but a closer comparison between the table of electronegativity values and galvanic series reveals significant differences. If you connect steel with Zinc then Zinc will be damaged (galvanically corroded) and steel close to Zinc remains unharmed. Thats why Zinc plates is used for the galvanic protection of ship parts that are made of steel.

[@MrSteves25]

Can galvanised pipe be used with high pressure steam at 160deg C

[@pellyrat1]

thanks

[@CaptainCorrosion]

and thank You for watching =)

[@roomeolove3838]

Thank you very much for this vedio, and ihave quastion: I JOINTED a carbone steel pipe (ASTM A106) with (brass/bronze ) valves by threaded joint, does that made a galvanic corrosion when thy are jointed in air without any liquid? THANKS AGAIN

[@CaptainCorrosion]

In that case it would depend on the average moisture level in air. Try to combine carbon steel and brass in the galvanic corrosion simulation tool and play with the levels of humidity as well as temperature.

[@Jamiera475]

Can galavanic corrosion occur between two noble metals? And if so, how severe would it be?

[@shinystar1928]

Thaanx alooot

[@CaptainCorrosion]

you are welcome!

[@lighthouse6120]

Thank you for this education. I would like to know more about the consequences of bonding copper directly to steel in concrete. (For the construction of concrete swimming pools) . When bonding in concrete, should a (brass/bronze) bonding clamp that isolates the copper from the steel be used ? In order to prevent the concrete from spalling later ? (Also called spaulding). Does this reaction cause outward expansion of the steel cage inside the concrete. Does this cause spalding of the concrete ? Thank you

[@CaptainCorrosion]

That's a tough one. You see, corrosion of metal structures in concrete takes place sooner or later if corrosive species such as water, oxygen and chloride can reach the metal through pores and cracks. So it all comes down to the quality of concrete and external factors. As for combining metals inside, I'd say you could see galvanic corrosion (as well as uniform corrosion) either way, which starts degrading the concrete even further. That's because the brass/bronze clamp is still a good electrical conductor, which allows the galvanic corrosion to take place. Perhaps applying a spray paint on the copper-steel connections could help but then again concrete has to be alkaline to slow down corrosion and this may have a negative effect on the paint.

[@woodatwork6927]

Great Video. In it you said that if an aluminum frame gets bolted together with steel bolts, it will cause corrosion and come apart. Would the same happen if you used stainless steel bolts?

[@CaptainCorrosion]

Probably, check the simulator or galvanic series to be sure. Of course there are ways to counter galvanic corrosion even if you use stainless steel bolts to connect aluminium parts :)

[@antonis2814]

I have a galvanized boat trailer.I have put on it 3 sticks of magnesium stick which are in contact with the treiler.Do you think they can work as anodium,to protect my galvanize treiler?thank you for your time.

[@CaptainCorrosion]

Thank you for the question. Galvanized steel already has a zinc (or similar) coating, which acts as a protective coating and also as an anode in the case of defects in the coating. So I don't see much point in using additional cathodic protection in the form of your Mg rods. However, if the zinc coating is worn off in some parts, then these parts would require additional protection and immediate attention. So in these parts you could use additional cathodic protection with your rods.

[@garyd.alzagajr.4157]

In electrical construction when a building is built typically it must have a concert encased electrode. Typically this is done using a piece of bare copper wire place in the footing of the building. Their is quite a potential for contact between the copper and steel rebar in the footing. If a piece of copper is in contact with steel and they are incased together in moist concrete how intense will the galvanic corrosion be. What is likely to happen at the junction? Thanks.

[@CaptainCorrosion]

Hello, it really depends on the type of steel. Some steels have a similar activity as copper and there you wouldnt see conventional galvanic corrosion. However, a potential difference can also be created when the same material (or electrically connected metals) are exposed to different environments that have different concentration of oxygen, chloride and released metal ions - this would create a galvanic couple. Not sure how severe it is but when selecting the steel alloy for the application, be sure to check galvanic series in sea water (from internet) and make sure the steel has a similar electrochemical activity as copper or as close as possible.

[@vwb11356]

Maido, Thanks for the information. Your video was informative and at a level a novice could understand. I have a question about corrosion on my cell phone charging port. It would not power up one morning. It was very hot on the battery and unresponsive. I took it to my local Sprint store where the technician told me there was corrosion caused by water being on the port. They said it was water damage and it should be under a insurance claim. The phone was never wet and I take reasonable care of it. With that being said is it possible for the corrosion to occur without ever actually being exposed to water and would it have to get wet over and over again for the corrosion to occur. If there was a small amount of water it wouldn't it cause a small amount of corrosion and then dry up. The corrosion can not feed off its self and grow, correct. Could this have been caused by (1. a bad electrical connection) or (2. if any of the terminals had a coating of copper and it was worn down to a metal other than copper? ) After asking the technician to explain to me how corrosion works and he couldn't I have been researching and find it very interesting. I am Electrical Controls Engineer, but this is a bit out of my area. I would appreciate any help. Thank You

[@CaptainCorrosion]

+vwb11356 I left a more thorough answer on the mail but for those who are also interested in the issue - the corrosion of cell phone (and other small electric devices) is often galvanic by nature and the factors that contribute most are: moisture (water, sweat, moist air, condensation), bad design that leads to galvanic coupling, metal parts (e.g. circuits ) being exposed to air and not being coated with an insulating water proof coating, charging port not being sealed with the plastic piece and of course mechanical wear that removes the protective rust layer and re-exposes the fresh metal.

[@anonimanonimowy903]

Dobre Pomaranczowe

[@beuyoga9052]

Dear Captain, why do we use sacrified anode Aluminum in the subsea pipeline and the underground (soil) we use the Zinc sacrified anode ? As I know Zinc is more active than Aluminum ?

[@CaptainCorrosion]

I suspect its related to the difficulties of replacing the sacrificial anode and slower rate of corrosion. So for the subsea pipelines you might want to use aluminum (a lot of it) to provide long term protection, as it simply lasts longer (although it may provide less protection than zinc). Its also colder under the sea (less than 5 C) so the speed of corrosion is about 2-4 times lower than on top layers. The chemical environment is surely different there as well, so it may also play a significant role (e.g. less oxygen) in the type of corrosion. The change of pH in deeper layers also affects corrosion but it seems the pH itself depends more on the sea than the depth. If I´m wrong or missed something then be sure to correct me! Its an interesting topic.

[@user-bk3gj1he3o]

Content is great, but sometimes voice is low compared to background sound.

[@caterinas8090]

Thank you for the video and the simulator. I have a question. I'm screwing a ZincNickel coated Steel male pipe fitting into an Aluminum cast alloy. I didn't find the first material in your simulator or any coated steel. Do you think it's going to be ok? If corrosion could happen it can be only from moisture from outside. The fluid inside the circuit is ATF oil. Thanks a lot in advance!

[@CaptainCorrosion]

Look, you have lots of materials there and this turns it into a complex system. In such cases usually you can do corrosion tests to predict the corrosion behavior in the application environment.

[@caterinas8090]

I wish I worked in a company where important things as materials compatibility are considered in feasibility phase and not then have the project palmed off to me after the sale is made and SOP is near... I'm trying to make a corrosion test happen but many dark forces in the company are impeding it... If I could perform a test easily I wouldn't be here at 2am.. Thanks anyway for the swift reply . Companies (and the world!) need more people like you!

[@CaptainCorrosion]

@@caterinas8090 I'd prepare mockups that mimic the real thing and do tests with these. If external moisture is most likely source of corrosion, then I'd consider long term immersion tests, short term chemical tests and a salt spray test. Maybe also an electrochemical test, depending on the budget.

[@CaptainCorrosion]

@@caterinas8090 If you still need and it fits in your budget, then we can do some of the corrosion tests at our R&D centre. For that you'd need to contact us through our website for a quotation. If we don't have too many projects at the same time, then you can expect the tests to be done quite fast.

[@TheMatrixgod]

can you explain,i have a aluminum boom on my boat that sits on a metal piece and as the years go by its getting corroded the aluminum where it sits on the metal and its scaring me,can i put say a anode zinc on the boom so that the corrosion stops,or like painting where they both meet,please help me here,thanks

[@CaptainCorrosion]

Heya! I think our team has dealt with similar issues in the past - feel free to contact us through the consultation page so our team can provide you with the most cost-efficient solution; captaincorrosion.com/consultation/

[@0715444067]

I have Cast iron Flanged valve. I want to continue with SS pipe. So if I use SS flange to connect with Cast iron flange is there any serious galvanic corrosion in future?

[@CaptainCorrosion]

Hello and thank you for the question! We have cast iron and a number of stainless steel alloys in our galvanic corrosion simulator so you can play with the choices and see what works best for you. But in short, it is likely that you will experience galvanic corrosion if you combine cast iron with some SS alloys - the question is rather how severe it will be.

[@uvarajm86]

Hi maido.. Video was really informative and useful.. I have one question. If the two metals are separated by insulation and if I connect one wire to both the material in presence of insulation, Will the galvanic corrosion take place???

[@CaptainCorrosion]

+Uvaraj M Hello! As long as the electron can move from the active metal to passive metal in the presence of corrosive medium, galvanic corrosion will occur. If you do the wire thingy, then two things need to be taken into consideration though; 1. How does the wire material stand in the galvanic series? If the connections of the wire are also exposed to the electrolyte then it would play a role. 2. The length and resistance of the wire matters! If the wire is too long or has higher resistance then electrons will have a hard time getting from one metal to the other and thus galvanic corrosion will be much slower in comparison with a case where you have a shorter wire.

[@uvarajm86]

Hi captain corrosion! Thanks for the reply. Let us consider two pipes with different materials (Carbon steel and stainless steel) carrying sea water and is connected through bolts with insulation material inbetween, and if i connect 14 gauge wire (Low resistance) of 50 cm length on the external surface of pipe, will the galvanic corrosion takes place?? Here the wire is not in contact with electrolyte but it is capable of transferring electrons..

[@CaptainCorrosion]

+Uvaraj M Galvanic corrosion of carbon steel pipe should take place in this case but it will be limited by the resistance of the wire. The corrosion takes most likely place on the inner side of the pipe as close to the wire connection outside as possible (perhaps in a 1 meter radius or less). Also the outer part may be vulnerable to galvanic corrosion if they are not coated properly and are in a moist environment or if water condensates on the cold surface of the pipe close to the connecting wire. Thats all in the case that the bolts and pipers are properly insulated from each other =)

[@uvarajm86]

In my case, if the wires are not connected to the pipes, the static current will accumulate at the end of connection (where the insulation material is placed), which will result in the damage of pipe. So the pipes should have seperate wires grounded, which will help to dissipate the electrons accumulated at the pipes. Thank you so much for your valuable reply Captain corrosion...!!!!!!

[@CaptainCorrosion]

+Uvaraj M That would rather sound that electrons are leaking through your insulation from one pipe to another. During the connection of pipes the insulation may have been damaged (can happen very easily) and lead to an electrical connection. When you use the wire to connect the pipes then you simply delocalize the corrosion over a broader area so its still there but perhaps doesnt cause local damage as fast. About static electricity im not sure - if electrons should accumulate in a pipe then the pipe would repel chloride ions and not corrode at all =) Although I cant see any charging happening there as any accumulated negative or positive charge would be carried away very fast due to interactions with the environment. So the only way for a metal to corrode fast in a corrosive medium is to take away electrons (galvanic couple or x-ray radiation), heat it up to higher temperatures or prevent the formation of a stable protective oxide layer (acidic environments, mechanical wear by flowing stuff or other interactions, nature of metal). In chromium containing steels a protective chromium oxide layer can form while in carbon steels the oxide is rather fluffy and that provides only limited protection (unless it is worn away by flowing substances).

[@martingarcia-vc2ws]

Graphite mixed with epoxy as adhesive between aluminium? could works?

[@CaptainCorrosion]

Hello and thank you for the question! And a difficult question that is. Normally I would avoid putting graphite and aluminium together as this would lead to the accelerated corrosion of aluminium component. However, an epoxy mixed with graphite may and may not be acting like graphite - it depends on the graphite concentration I suppose but also on the application (humidity and chlorine in air). You see, if the graphite particles are connected with each other, then they provide a path for electrons and if there are enough graphite particles exposed on the surface and reacting with water and O2, then you have met all the criteria for galvanic corrosion, and its speed will depend on the surface area of exposed graphite and the conductivity of the graphite/epoxy adhesive. So there is a good chance it might work but also a big risk and you wont know until its too late. In my opinion, I would try to find an adhesive without graphite if its a critical application but as a materials scientist, I would also carry out a corrosion test with two aluminium components bound by this graphite/epoxy and learn about its corrosion performance. In this corrosion test you might want to test different adhesives and compere them with each other and select the best one for your application.

[@cesarescobar9679]

Thank you for this informative video. Do you have ideas or suggestions on how to evaluate possible galvanic corrosion during an in-situ inspection (Not destructive inspection)? Thank you in advance

[@CaptainCorrosion]

Sometimes you can tell with naked eye that someone has messed up big time during construction but in other cases the corrosion consultant may need portable instruments worth about 50k EUR to perform analysis on site, which include materials characterization and structural analysis of relevant components.

[@cesarescobar9679]

@@CaptainCorrosion Thank you for the answer. In this case, employing portable instruments what kind of tests would be performed?

[@CaptainCorrosion]

@@cesarescobar9679 Possibly systems to study the composition of materials (e.g. handheld xrf or libs) and then something to see if there are internal cavities. The latter would be tricky if a decent ultrasonic system isnt enough.

[@cesarescobar9679]

@@CaptainCorrosiongreat, all these ideas are interesting. Additional to these analysis do you know if it is possible to perform an electrochemical test to identify the corrosion rate or activity?

[@CaptainCorrosion]

@@cesarescobar9679 Possibly there are some kits for that but I'm not familiar with those. I'd use a multimeter though to check if and where electrical contact is present between materials that can form a galvanic couple.

[@sheikhsarfaraz8150]

on which bases we will select the insulating material?

[@CaptainCorrosion]

Hello and thank you for the question. Most importantly it has to be resistant to water / moisture and be able to provide a proper seal if used to connect pipes for instance.

[@daravannmel4125]

Thank you for nice explanation. However, I have some question. In the substation,there is electron emission and current flow through electrical equipment. I connected copper wire to steel structure (galvanized steel) by using galvanize fasteners. After 1 to 2 years, my galvanized fasteners face corrosion. How to prevent this?

[@CaptainCorrosion]

Sounds like the zinc layer on galvanized parts has been depleted and that's where your protection against corrosion ends. If you don't want to change the parts, then you might consider some corrosion resistant spray paint if it can be used in your application. However, it will likely be a temporary solution.

[@daravannmel4125]

@@CaptainCorrosion how about permanent?

[@CaptainCorrosion]

@@daravannmel4125 Make things out of platinum! With corrosion, especially galvanic corrosion, there is no permanent solution. Unless of course you use materials that have exceptional corrosion resistance like platinum. With cheap materials companies usually do R&D projects with us and find the best cost efficient solution but that requires systematic studies and will pay off only if applied on mass produced parts.

[@daravannmel4125]

@@CaptainCorrosion Well noted with thank you!

[@uhjk91]

A steel pinch bolt has seized in an aluminium suspension arm, due to galvanic corrosion. What's the best way to get the bolt out? Is there a chemical I can use to break down the bond between the steel bolt and the aluminium arm?

[@CaptainCorrosion]

I think the chemicals are quite dangerous and mechanical approach is more appropriate. But if it is stuck due to galvanic corrosion, then you are dealing with aluminium corrosion products, which is a mixture of aluminium oxide and aluminium hydroxide. This stuff is normally removed in a surface cleaning process by utilizing warm alkaline (e.g. NaOH) and concentrated HNO3. So my first idea would be to try some of the alkaline pipe cleaning solutions available at the store if mechanical approach fails. Afterwards you'll need to rinse it with a lot of water to get rid of the alkaline for safety. The alkaline may also damage the surrounding aluminium though. With these chemicals you'll definitely need eye protection and latex gloves as a minimum and make sure you do not breathe in the fumes - do it in open air.

[@Ekleipsis3.0]

Hello, does anyone know which software is used in the simulations? It looks like solidworks

[@CaptainCorrosion]

I know! We actually used 3Ds Max back then to make these animations but it had a relatively high annual fee. If you are looking into cheaper alternatives, then you might want to check out blender.

[@kirubakaranmani4651]

If 2 different metals having 5 to 10mm distance is it possible for galvanic corrosion?

[@CaptainCorrosion]

No, unless you provide an electrical connection between these two materials.

[@parsleylion6313]

I understand that on old cars a plastic insulator was inserted between panels to stop G C. I was told that where the metal is folded, the material structure is different and therefore instigates an electrochemical process resulting in the corrosion. Is this true? if so how does the bending of steel change the local properties? How is the problem rectified these days?

[@CaptainCorrosion]

I'm not familiar with these structures and cant provide you with a satisfactory answer. From the description it seems though that there can be different forms of corrosion at play that may also have an electrochemical aspect to promote the progression of corrosion. With folded metals you may see crevice corrosion for instance, where differences of concentrations inside and outside of the crevice cause a potential difference and that promotes corrosion inside the crevice. Cold working may also cause microscopic cracks that may start act as anodic sites, where corrosion takes place at a greater rate.

[@CaptainCorrosion]

@@parsleylion6313 Please contact us through our official website captaincorrosion.com and use the contact form if you are looking for in depth consultation.

[@verlorenModus]

at home example: take one new american penny (the ones with the shield on the back) nick the copper plating to expose the zinc. it will take a few months, but that penny will crumble.

[@tonys9391]

What about sacrificial anodes? Do they work?

[@CaptainCorrosion]

In the case of sacrificial Zn anodes, the anode is the anodic part in most cases and at the same time the corrosion of the other metal is protected as long as the processes on the anode still take place.

[@spago555]

Thanks for the great video. QUESTION: I have a water-cooled engine with an iron block and aluminium head and I use a copper radiator for cooling it. Would the copper radiator cause galvanic corrosion even though it is not directly in contact with the Iron/Aluminium engine? Should I switch to an Aluminium radiator? Thanks again.

[@CaptainCorrosion]

Maybe its not too bad if the components are not electrically in contact with each other. Also, if you use demineralized water for cooling, you can significantly slow down galvanic corrosion. In any case, having similar components in a system should decrease the risk of galvanic corrosion (unless the medium itself is bad for aluminium or if steel causes aluminium to corrode rapidly).

[@spago555]

@@CaptainCorrosion hmm yes the system uses antifreeze which isn't a good conductor so I am guess that slows down the corrosion. Question: Doesn't the oxidation layer on Aluminum prevent galvanic corrosion?

[@spago555]

@@CaptainCorrosion And thanks for the reply and sharing your knowledge 😊

[@CaptainCorrosion]

@@spago555 It depends on the antifreeze too. Some can inhibit the corrosion a great deal. We actually had an idea of developing a coolant liquid that also inhibits corrosion in complex systems, where galvanic corrosion could become an issue over time. Such coolant could be sold in a barrel to large industrial consumers at a reasonable cost.

[@spago555]

@@CaptainCorrosion Not a bad idea. I'm surprised as to how little information there is on the internet about this. Maybe this is a topic you can talk about on future video. One last question: How can I utilize a sacrificial anode in this situation? Can I simply just attach a piece of since to the inside of the radiator? Can the zinc be attached to the outside as well?

[@Jamiera475]

So if I had a piece of platinum and gold touching eachother, gold will start to corrode?

[@CaptainCorrosion]

Probably not in normal ambient conditions. In some harsh chemicals it may be possible though to see accelerated corrosion of gold in a gold-platinum coupling.

[@husaink]

What if there was no contact between the two metals? How come the steel get corroded if it was left at an open area area with humidity and water? What will be anode and cathode?

[@CaptainCorrosion]

If your steel is not in direct contact with other metals, then you are likely dealing with uniform corrosion (aka general corrosion), which depends on the environment as well as the material. Check out the theory on uniform corrosion and play with the simulation tool; captaincorrosion.com/general-corrosion/ captaincorrosion.com/uniform-corrosion-simulator/

[@husaink]

@@CaptainCorrosion thanks captain, in my case if you have a storage tank, how to identify anode and cathode? If there was no CP system installed.

[@CaptainCorrosion]

@@husaink If the whole storage tank is made out of same material, then you are probably dealing with uniform corrosion and the anodic and cathodic areas migrate around in a microscopic scale. However, the system may have components that are made out of a more noble alloy than others. Those parts would suffer no corrosion and be cathodic while a nearby component of a more active metal would become anodic and suffer more corrosion. In any case I'd recommend using some weather resistant paint to slow down the corrosion or consider galvanic protection (e.g. by using zinc anodes).

[@husaink]

@@CaptainCorrosion Thanks Captain, I really appreciate your response.

[@tytck70]

Hi, I watched n liked your video. Its easy to understand. I'm now working on a project that is to mount a stainless steel plate on the high tensile steel baseplate. I did a search for the galvanic chart, however, high tensile steel is not in the list for me to understand the potential difference between these two materials. So how can I find out? What would the potential difference? Which would corrode? Pls help. I thank u.

[@CaptainCorrosion]

I would plan a series of corrosion tests to see if there is any risk of galvanic corrosion or other forms of corrosion (e.g. crevice corrosion).

[@tytck70]

From the galvanic series chart, how do I determine the volt for stainless steel 316L (passive) for example? Looking at the band, I'm not sure how to. Kindly help. I thank u.

[@CaptainCorrosion]

@@tytck70 I'd advise you to use our galvanic corrosion simulation tool. If the tensile steel doesn't contain much nickel or chromium, then you can replace it with cast iron in the simulator. For the other metal you can select the SS316.

[@Robin0201]

Hello there Captain. In our water supplies we make sure the anode pipe has a bigger surface than the cathode to reduce corrosion. Also, if we have to fix a leak we put plastic pipe instead of copper between a galvanic pipe. In some systems both copper and galvanic pipes are still connected. Even if we put a plastic pipe between copper and the galvanic steel pipe, shouldnt the water act like a electrolyte and still make steel electrons move to copper? Alas, less due to plastic pipe in between but still some increased movement?

[@CaptainCorrosion]

I think your approach is reasonable and should work well. If you put plastic between copper and steel, then you no longer have a galvanic couple between the two parts if there is no other electrical contact between them. So you should expect more or less uniform corrosion (or pitting corrosion in some cases), which depends on the electrolyte, pH, content of chloride ions and temperature.

[@Robin0201]

@@CaptainCorrosion thank you, so for clarification we still get corrosion but much less, all depending on the water (the electrolyte?).

[@Robin0201]

@@CaptainCorrosion oh and 1 last question. Can iron particles (from a heater) that dissolved itself (oxidation) into the pressurized pipe system cause pitting in copper? In that case how? Thank you for your time

[@CaptainCorrosion]

@@Robin0201 Yeah, the properties of water will have a huge impact on the rate of corrosion.

[@CaptainCorrosion]

@@Robin0201 Metallic iron is more active than copper, so even if it deposited on a copper surface, it shouldn't cause localized galvanic corrosion. The pitting corrosion of copper has something to do with its surface. For some reason a vast area becomes cathodic and a site anodic, where the pit starts to form. It can be an issue with the alloy (uneven composition or specific crystal structure). Maybe your system also causes the formation of passive layer on top of copper (maybe iron has a role in it) and since it has defects, the defects have exposed copper and may become anodic. This possibly is a more complex problem that can be studied in detail through literature and experiments with a sufficient budget =)

[@rajeshperumala2879]

Why the corrosion occurs only at anode

[@CaptainCorrosion]

As mentioned in the video, the corrosion needs two simultaneous electrochemical reactions to take place - one at the anode and one at the cathode. This happens if two metals with a different electrochemical activity are in an electrical contact in a corrosive environment - the greater the difference in activity, the more rapid corrosion of the anode component.

[@Moondisapear]

Hi doctor I am from Iraq I have questions why Why can't the aluminum tube be used with copper or copper ions and what is the corrosion by deposition

[@CaptainCorrosion]

Hi! If copper is in electrical contact with aluminium, then galvanic corrosion of aluminium would occur if the electrolyte is corrosive. Alternatively, corrosion can also occur if the two metals are not in contact. In that case copper may be transported with the electrolyte and redeposited on aluminium, where it will cause localized galvanic corrosion.

[@DheerajSingh-hc7wy]

I want to know about concentration corrosion

[@CaptainCorrosion]

I'm planning to make a video about that at some point. Concentration corrosion is also electrochemical by nature and takes place if a metal is in contact with different concentrations of the corrosive media. An example would be a steel rod in sea water reaching from the sea floor to the surface. The concentration difference of oxygen in the top layer of water from the bottom layer would result in a potential difference and cause corrosion in the anodic part.

[@kevinalexander4240]

localized corrosion

[@robbytandiono3376]

what i means i want to show u the picture of cooroded metals which is used zinc anode..would u mind if i sent it to you via mail?thanks for your assistances.

[@CaptainCorrosion]

+robby tandiono You can find the contact in the about section of this channel :) sure, send the pic!

[@SuperVendetta9]

Why does this sound like the Home Depot aka; *Hone* Depot (deeper)? Honestly, the pitch got deeper.

[@05boykeanandadwiapriyantot48]

how to make that kind of video ?? please

[@CaptainCorrosion]

Study a topic thoroughly, learn how to teach at a university, learn 3D modelling and animations, learn video scripting and editing, learn SEO, learn how to make a viable business and then you'll make videos just like this and after years of practice the quality only improves!

[@kingjeremysircornwell7847]

The universe is made of electrical corrosion :)

[@champcv1]

It's me Boselecta

[@robbytandiono3376]

To : captain corrosion, Good day there, i am robby, i would like to need your thoughts and advise to see my used zinc anode if this working in good condition or not.please advise your email adds if possible,i will sent the pict of zinc anode. Thank u

[@CaptainCorrosion]

+robby tandiono Hello! As long as you still have metallic zinc left that can be in an electrical connection with the protected (assuming steel?) substrate, protection should be applied. So be sure to refresh the surface of the anode and check the electrical connection with the other metal.

[@ThePipeiper]

So no one else sees the monkey, moth, fox, buff dude at 3:00 in the middle of the blue anode???

[@AA-uu9ik]

Not enough quality heads for all the bodies

[@Thingvallavatn]

We don't learn much from this video, because you don't explain what “active” metal is. It is essential to explain (briefly) what the electronegativity scale of metals is, so that everyone can understand the couples that must be avoided

[@riasrivastava5526]

Thanks a lot! Such a wonderful explanation! BTW, are you Japanese? Your accent sounds like that 😅

[@CaptainCorrosion]

Hi! Thanks for watching the video. Estonian language does indeed sound a bit like Japanese so perhaps that explains the accent ;)

[@badblood18]

came here after the titan disaster.

[@CaptainCorrosion]

If I remember correctly, then the Titan used a lot of carbon fiber material parts. Nowadays it is becoming more widely known that carbon fiber material can actually promote the galvanic corrosion of other metals that are connected to it. This is because oriented carbon materials, including the carbon fibers, are more cathodic than other metals. As a result, materials like aluminium alloys would be particularly endangered when combined with carbon fiber composites. In applications such as the Titan, which include total immersion into saltwater, thorough long-term corrosion tests should be done to asses the corrosion resistance of individual materials and when they are combined. In non-critical applications we normally go for at least 1000 hour long corrosion tests in synthetic seawater but in the case of a submarine I'd recommend 6 months just to be sure.

[@germanvaz7526]

sexy voice, damn

[@abhishekgogoi5046]

Stop with these background music s please :)

[@0715444067]

I have Cast iron Flanged valve. I want to continue with SS pipe. So if I use SS flange to connect with Cast iron flange is there any serious galvanic corrosion in future?

[@saleemsikander4226]

Use rubber or non metallic gasket also use insulation sleeve on bolts