corrosion of steel,fundamental academic and industrial problem, use of inhibitors, practical methods,materials , in acidic media,N-heterocyclic compounds most effective corrosion inhibitors, inhibition action,adsorption on the metal surface, blocking the active sites, molecules and forming compact barrier film, to decrease the corrosion rate, adsorption of N-heterocyclic inhibitor, nitrogen heteroatomu , with triple or conjugated double bonds,aromatic rings,inhibition efficiency, organic inhibitor,increase with the number of aromatic systems ,electronegative atoms in the molecule,