doraamy Posted February 13, 2010 Share Posted February 13, 2010 I'm now doing a science project about rust converting. I use tannic acid and phosphoric acid to react with rust to form a complex, which in turn protects the iron. when i did the exp, a blue-black coating was formed, which should be the iron-tannate complex, but the coating was somehow detached no matter how long i react the acids with rust. What can I do to improve the process? Link to comment Share on other sites More sharing options...
escfmcmt Posted February 21, 2010 Share Posted February 21, 2010 Frankly speaking I’m not quite familiar with rust converting. But I think the reason of this failure is that the acids can’t penetrate very well. Maybe you can add some organic solvent to bring the acids into the rust… Keep going! Link to comment Share on other sites More sharing options...
Externet Posted February 21, 2010 Share Posted February 21, 2010 Immersing a rusty iron piece in baking soda solution and applying 12 volts electrolytically removes the iron oxide. Many years ago, an expert told me that immersing a rusty piece in caustic soda, would prevent from rusting ever again Link to comment Share on other sites More sharing options...
Mr Skeptic Posted February 27, 2010 Share Posted February 27, 2010 I've heard that too... not sure on the details. Link to comment Share on other sites More sharing options...
Newbies_Kid Posted February 27, 2010 Share Posted February 27, 2010 Maybe you should know what the blue-black coating is before making any conclusion.. You can try using the XRD to analyze the composition. Maybe the composition of the coating is somehow still active or chemically unstable before forming a protective passive layer. My english is sadly poor but I'm proud to be Malaysian :') Link to comment Share on other sites More sharing options...
insane_alien Posted February 27, 2010 Share Posted February 27, 2010 Immersing a rusty iron piece in baking soda solution and applying 12 volts electrolytically removes the iron oxide. Many years ago, an expert told me that immersing a rusty piece in caustic soda, would prevent from rusting ever again http://en.wikipedia.org/wiki/Passivation what happens is that you form a thin layer(pretty much just a few molecules deep) on the surface of the metal that prevents oxygen getting to the metal and corroding it. Link to comment Share on other sites More sharing options...
Newbies_Kid Posted February 28, 2010 Share Posted February 28, 2010 (edited) Immersing a rusty iron piece in baking soda solution and applying 12 volts electrolytically removes the iron oxide. Many years ago, an expert told me that immersing a rusty piece in caustic soda, would prevent from rusting ever again I don't really sure but i would say that the primary corrosion product of iron is Iron hydrous oxide (Fe(OH)3) not iron oxide. Iron oxide is more tend to form iron hydroxide (red-brown rust) when exposed to humidity. the expert may be right.. but rusting will only stop as long as the piece is immersed in the solution http://en.wikipedia.org/wiki/Standard_electrode_potential Edited February 28, 2010 by Newbies_Kid Consecutive posts merged. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now