Abstract
In corrosive media, metallic surface can generally be protected with adsorbed film of organic corrosion inhibitors. In neutral solution, more enhanced effects can be expected by high molecular-weight inhibitors which are insoluble in the media. These inhibitors should be dispersed in it. Well-dispersed ones can be easily adsorded on metallic surface, but easily depart from the surface, and they give ineffective inhibition. Diamines, such as n-dodecyl propylene diamine and n-octadecyl propylene diamine can be made more and more dispersible with the increase of mole ratio of H2SO3/diamine. Several diamine salts with different amounts of H2SO3 were selected as inhibitors and their inhibition efficiencies on mild steel were examined in NaCl aq. solution. In conclusion, hardly dispersible inhibitors were more effective than those which were easily dispersed in their own abilities or by additional surfactants in agitated solution.
