A CRITICAL REVIEW OF CORROSION INHIBITION BY PHOSPHONIC ACIDS

摘要: Phosphonic acids are effective chelating agents.  They bind tightly to metal ions.  have been widely used as corrosion inhibitors along with various ions such Zn 2+ .  The of metals mild steel, copper, and aluminium prevented by phosphonic acids.  exhibit good inhibition efficiency in acid medium, alkaline neutral medium.  can be other calcium gluconate, sodium molybdate, trisodium citrate.  show synergistic effects these inhibitors.  Various surface analysis techniques FTIR spectra, SEM, AFM, EDAX analyze the nature protective film formed on surface.  Usually, consists Fe -phosphonic complex Zn(OH) 2 if is used.  When prevent iron, adsorption process obeys Langmuir isotherm.