The authoritative public forum
  for Metal Finishing since 1989
  

  -----

How wet corrosion works

2007

Hi there. I'm a high school student in garde 11 and I am doing an assignment on corrosion and finding it extremely difficult to understand and explain how wet corrosion works. I was wondering if oxidation actually involves the metal dissolving, as some information I have found has mentioned that it does so that the dissolved particles then react with the oxygen? I was also wondering why exactly steel rusts faster than pure iron does. and lastly why exactly does salt increase the rate of corrosion?
any help would be greatly appreciated.
thanks

Ashlie S.
student - Brisbane, Queensland, Australia

---

2007

Hi Ashlie,

Corrosion NEEDS humidity, it NEEDS moisture ...t'other wise if it's dry, you shouldn't get any corrosion, eh?

Why does, you ask, iron corrode more quickly than steel ?

Surely that depends upon the 'ingredients', ie. the alloys in it .... ordinary iron has quite a higher Carbon content than steel and can possess some sulfur and phosphorus ... after all, steel is MADE from iron by a refining process (open hearth or electrical furnaces) to knock out the S and P and reduce the carbon content

Salt is an alkaline ... eg. seawater ... and that can eat up/reduce both steel and iron.

I hope that that helps.

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).