Some furfural hydrazone compounds as corrosion inhibitors for iron in nitric acid

The corrosion behaviour of iron in M HNO3 containing furfural hydrazone derivatives was studied by electro‐chemical, polarographic and scanning electron microscopy measurements. Polarization data indicates that all inhibitors tested were of a mixed type, affecting both the cathodic and anodic processes. The inhibition efficiency of the additives increases in the order I<II<III<IV<V. It was found that the compounds under consideration are adsorbed on the iron surface. The degree of surface coverage is influenced by the presence of functional groups and interaction between adsorbed molecules. Within the given homologous series the contribution of the functional group to adsorption increases with the length of the chain.