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I'm very interested in measuring corrosion in metal alloys, particularly in salt solutions. I understand metals corrode over time, however, I was wondering if it's possible to electrochemically "speed up" or induce further corrosion in saline solutions? How would I go about this electrochemically? I've considered applying a specific current / potential and utilising it to induce oxidation, however, I have not found much in the way of literature actively seeking to induce / speed up corrosion, most are content to investigate over longer time periods.

Many thanks.

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Yes you can!

I would suggest one of two methods for you the Electrochemical one known as Electrolysis https://en.wikipedia.org/wiki/Electrolysis which is somewhat scalable to your need (Just make sure you don't fill your room with chlorine gas) or Galvanic Corrosion which is passive and safe but slower https://en.wikipedia.org/wiki/Galvanic_corrosion

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  • $\begingroup$ How would you go about inducing electrolysis with aluminium? Setting copper as the cathode, immersing the aluminium in salt water and then applying a potential? $\endgroup$ – Gareth Jan 15 at 11:56
  • $\begingroup$ Electrolysis of aluminum is usually called "Anodizing" and is done in sulfuric acid; there must be whole books on the subject. $\endgroup$ – blacksmith37 Feb 15 at 16:13
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Since I can't comment I'll add this new response:

  1. It needs to be DC
  2. Rust will fall of the negative electrode and form at the positive IIRC
  3. If the current is too high you'll form chlorine gas so you might want to use baking soda instead of salt. At the minimum do it outside.
  4. If you want Aluminum oxide then make sure you only immerse aluminium on that side
  5. Don't try to get Iron Oxide from stainless steel as that can create certain toxic heavy metals.

  1. Read more than what I say, it's been quite some time since I did this and some information might be incorrect.
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Corrosion is a more or less involuntary/undesired reaction. If you apply a current, the corrosion is defined by the current you apply, so you are controlling the system, not just observing it. In general, electrochemical forcing puts your system into a highly unnatural regime, but can certainly provide interesting information.

Corrosion can be affected (in ways that you can determine and document) by temperature, by contact with other metals, by the corrosivity of the solution (concentration and specific ions), and by inhibitors.

Some time ago, we were interested in stress-corrosion cracking (failure) of stainless steels. Hydrogen, (slowly generated in a natural environment) would embrittle the steel. By increasing the corrosivity of the solution (chlorides) and adding an activator (sulfides), we were able to speed up the hydrogen evolution/absorption so that steel specimens under tensile stress would fail within days or weeks, rather than months or years in nature. This enabled choosing alloy compositions that were most resistant to stress-corrosion cracking.

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  • $\begingroup$ Alloy composition has little to do with hydrogen stress cracking ; it depends on strength level and to some degree on stress and microstructure ( once hydrogen is in the matrix). Austenitic stainless ( non-magnetic ) , and ferritic stainless are more or less immune. Martensitic stainless is susceptible under the same conditions as carbon and low alloy steels. Sulfides cause H entry , not evolution, that is why the international standard ( MR 01-75) is based on the level of hydrogen sulfide. $\endgroup$ – blacksmith37 Jun 16 at 20:00

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