1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Ferric oxide : protective or not?

  1. Apr 30, 2015 #1
    1. The problem statement, all variables and given/known data
    There are two lines in my textbook :
    " Iron is passivated by strong oxidising agents like conc.##HNO_3,K_2Cr_2O_7## due to the formation of a protective coat of ##Fe_2O_3##."
    And the other line says:
    "Rusting occurs in the presence of ##O_2,H_2O## and ##H^+## resulting in the formation of ##Fe_2O_3## which is not protective and the corrosion continues"
    Whats this? One line says that ##Fe_2O_3## is protective and other says it is not !

    2. Relevant equations


    3. The attempt at a solution
    Can it be the reason that protective property of ##Fe_2O_3## is different for different conditions?
     
  2. jcsd
  3. Apr 30, 2015 #2

    Borek

    User Avatar

    Staff: Mentor

    Apparently. Concentrated nitric acid is safely transported in steel tanks, as the iron from these tanks gets passivated and doesn't dissolve in the acid. Same steel will rust if put in sea water.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Ferric oxide : protective or not?
  1. Cathodic protection (Replies: 4)

Loading...