Pourbaix Diagram and Corrosion Engineer 1

[SZignus]

Hi all,

I am new here and also new for working in this field. I have a common question for you guys about Pourbaix diagram.

1.) From my understanding, the beneficial of this diagram is for corrosion of Fe exposured to water ( H2O Stability is in the red line ).
It shows us which kind of corrosion (general/localize) will be found in each pH. Is that all I could earn from Pourbaix diagram ?
(Potential cant be defined because it comes from many sources such as Flow rate, Flow velocity etc.)


2.) Have you ever used this diagram for the real work ? Please give me an example.

Thanks for your sharing and your dedication.

 

[SZignus]

https://www.google.co.th/search?q=p...3avwnHD2pym6M%3A;mgzMnIfFjfFdpM;http%3A%2F%2F

http://www.corrosionclinic.com%2Fco...rosion_online_lectures%2FME303L07.HTM;679;561

The "Dash line" not the "Red line" sorry

 

[CoryPad]

The Wikipedia article on Pourbaix diagrams gives a good overview.

The diagram does not provide information about types of corrosion, it provides information about the thermodynamically favorable species.

A general use is to find pH conditions where the metal is passive, e.g. alkaline conditions for iron and acidic conditions for aluminium.

Another usage is to give a general guide of how much potential is needed for a cathodic protection system.

The next step is to take the potential information from the Pourbaix diagram and obtain Tafel plots which then can be used to estimate current density which is similar to corrosion rate.

 

[EdStainless]

You can also look at diagrams for other species that are in you system and see what they are likely to breakdown into. this is the most common reason that I look at them.
Someone tells me what chemicals go into the system, but I want to know what the active species really are.

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P.E. Metallurgy, Plymouth Tube