How does Pitting corrosion occur? /Localised corrosion: Electrochemical corrosion

[@sajidhasa5209]

may be you should join VIT mam.-VIT STUDENT.

[@RevathiPurushothaman]

Thanks for your suggestion.

[@suryaanshjaiswal50]

yessss

[@konstantinshalnov6288]

Best explanation of corrosion on KZbin!

[@RevathiPurushothaman]

Thank you so much.

[@johnberger4948]

This was a great teaching!! This is helpful for my level 2 inspector exam

[@RevathiPurushothaman]

Thank you. It's my pleasure.

[@chemengineer2006]

you are doing a very good job , my respect

[@RevathiPurushothaman]

Thank you very much.

[@chemengineer2006]

I am Corrosion Engineer and plan to listen to your videos , you present corrosion science in a simple way

[@RevathiPurushothaman]

There are nearly ten videos on corrosion and its control. You can watch if it is relevant to you.

[@suthanprasad]

Nice presentation mam easy to understand ur explanations

[@RevathiPurushothaman]

Glad to hear that. Thank you.

[@jayeshahirrao3868]

Wow superb 😍 it just cleared all me doubts ❤️

[@RevathiPurushothaman]

Thanks for your compliments.

[@Indiansports421]

Can u telle how to make cold phosphate chemical for grey colour coating?

[@andippankavitha2509]

Excellent presentation

[@RevathiPurushothaman]

Thank you very much.

[@kedardhane.1163]

Very clear explained, more that book.

[@RevathiPurushothaman]

Thank you. Glad that you liked it.

[@chandramoulijeyaram8524]

Mam, if I give earthing of battery on cast iron and if there is a rubbing happening on one particular point on it will become similar case as you said large cathode and small anodic area??

[@RevathiPurushothaman]

Not just by rubbing, because a single metal is present here and it cannot remove any coating. But if something which is rubbing is a small area and constantly in contact with the metal, then the metal underneath that small contact area will act as anode and undergoes differential aeration corrosion and also pitting corrosion.

[@viveksurendran9505]

Thank you for this video.

[@RevathiPurushothaman]

You are most welcome.

[@suhailfsheikh7596]

So of it is completely immersed , what type of corrosion will take place? Pitting or galvanic?????

[@RevathiPurushothaman]

If both the metals in contact with each other and are in presence of a corrosive medium, then galvanic corrosion occurs.

[@svanitha3272]

Nice explanation

[@RevathiPurushothaman]

Thank you very much.

[@MuhammadUsman-pq8iz]

Mam you're doing a wonderful job please upload more videos like these and I've one question which protection is the most economical among them and why?? Please reply mam

[@RevathiPurushothaman]

Thank you. This cannot be answered in one sentence. We need to choose the method based on the situation and condition. Each method has its own pros and cons.

[@MuhammadUsman-pq8iz]

Okay Thank you so much mam for the quick reply ☺️

[@RevathiPurushothaman]

Most welcome.

[@ramakrishnan6913]

You said pitting corrosion can be prevented if the anodic area is larger compared to cathodic area . How this can be possible in case of differential aerated corrosion . Please give an example

[@RevathiPurushothaman]

In this example, prevent dust accumulation. Good maintenance can prevent.

[@Placement360India]

What is the driving force behind the conversion of Fe to Fe 2+....

[@RevathiPurushothaman]

Generally most of the metals are unstable, except some noble metals. All metals tend to go the combined state rather than being in its metal state. In both the cases, when iron acts as the anode, it undergoes oxidation i.e. Fe to Fe2+. The driving force for corrosion depends on the electrode potential of the overall reaction.

[@Placement360India]

@@RevathiPurushothaman can I not say that the atmospheric O2 being an oxidizing agent wants electrons whenever he finds a region which is rich in electrons( in this case Fe metal) and so Fe becomes converted into Fe2+ ?

[@RevathiPurushothaman]

Your argument may hold good for dry corrosion, where the oxygen present in the atmosphere oxidises the metal. But in this case it is wet corrosion (electrochemical corrosion), where the corrosive medium plays a major role to drive the corrosion.

[@Placement360India]

@@RevathiPurushothaman yes ....now I'm satisfied....thank you♥️

[@RevathiPurushothaman]

You are welcome.

[@suhailfsheikh7596]

Ma'am if a small steel pipe is placed in a large copper tank, Steel- Anode(small) Copper- cathode(large) So will the corrosion be pitting corrosion?? Or will it be differential metal corrosion??

[@RevathiPurushothaman]

It depends on how it is placed. If it is immersed completely, corrosion will take place evenly on all sides of the mild steel pipe. Only if a small portion is exposed like a scratch in a coating, pitting corrosion will occur.

[@iamsosweetgahayah2977]

Wow superb explanation mam

[@RevathiPurushothaman]

Thank you.

[@teamtamilans6955]

Nice I like ur explanation tomorrow semester exam I am presenting ur vedio in answer paper

[@RevathiPurushothaman]

Thank you.

[@AbhishekDixit-y5x]

mam please make a video on intergranular corrosion

[@RevathiPurushothaman]

Sure

[@janand78]

Thank you for your efforts Can able to get contact I need for Class NACE Senior corrosion technologies course

[@RevathiPurushothaman]

Thanks a lot.

[@786karthik]

Fantastic

[@RevathiPurushothaman]

Thank you.

[@shahnawazsamejo3847]

If anode area larger than other type corrosion will not accur?

[@RevathiPurushothaman]

It can lead to galvanic corrosion or differential aeration corrosion etc, but it will to drastic corrosion, which will be in the form of pit. Hence pitting corrosion also.

[@afsharhamed718]

Awesome video, I have few questions in regards to galvanic corrosion, would it be possible to contact you directly? its in regards to a product i have developed and unfortunately during the spray salt test 200 hr, it was a non compliance, if you could assist me that would be highly appreciate

[@RevathiPurushothaman]

Thank you. Describe the problem. We will see what could be done.

[@mithuandoviailovemymothers6716]

Thankyou mam

[@RevathiPurushothaman]

Most welcome.

[@amolmali1308]

Excellent madam

[@RevathiPurushothaman]

Thank you very much.

[@divyadurga358]

Very nice explanation madam,thank you so much mam😊

[@RevathiPurushothaman]

Glad that you liked it.

[@sruthipanuganti627]

Good explanation and thank you

[@RevathiPurushothaman]

Thanks

[@rchopra386]

I am highly impressed and feel respect for u. I am in a d&a company and have got some technical doubt? It will be very helpful if u could give ur mail.

[@RevathiPurushothaman]

Thanks for your compliments and support.

[@rchopra386]

@@RevathiPurushothaman Mam we are struggling a lot due to pitting issue in. Al- AA2014. Can u suggest some preventive measures. As of now we apply SAE 30 oil .

[@rchopra386]

Mam i m waiting for ur reply.

[@gkpatilpatil6588]

Good morning

[@RevathiPurushothaman]

Good afternoon sir. Thanks for your participation.

[@ramakrishnan6913]

If the oxide layer breaks up , this oxide layer forms immediately, say S.S, Copper,Al,Ag mtrls.etc. In that cases corrosion should not occur.

[@RevathiPurushothaman]

Oxide layer will form immediately only in case of passive metals such as Al, Tii etc.

[@R_o-c_k_s_t_a_r]

Thanks

[@RevathiPurushothaman]

Most welcome.

[@kasipavankalyan9109]

the best

[@RevathiPurushothaman]

Thanks

[@rahulrgd4128]

May be translates in Tamil But think pls Oru meanings pls Explaintion must in Tamil

[@RevathiPurushothaman]

Only limited number of audience can be benefitted, if explained in the vernacular language. You can watch any no. of times to understand.

[@awakenhindu2513]

Best

[@RevathiPurushothaman]

Thank you.

[@gurunathshinde4552]

Nice Information... Madam can I get ur email id as I have some doubt in my work about Corrosion