Corrosion Inhibition of Cu- Fe Alloys in HCI Solutions by Amphoteric Surfactants

amphoteric surfactants were tested as corrosion inhibitors for the cu- fe alloy corrosion in 1m hci solutions. weight - loss, electrochemical polarization, impedance measurements and atomic absorption spectroscopy were the techniques used. the surfactants were alkyl-n- (amino ethylene) - β - aspartamates of molecular formula: h2 n- ( ch2)2 - hn- ch -cooh , ( r=c10 - c 14 ). ch2 conh-r these surfactants behave as mixed - type inhibitors, i.e. they affect both the cathodic and anodic reactions without changing their mechanisms. the inhibition action of these surfactants may take place through blocking and hydrophobic effects. the inhibition effect increases with the increase of the alkyl group (-r) length. these surfactants were adsorbed in the alloy surface according to the frumkin isotherm model. the presences of these surfactants in the aggressive media contribute to increases the values of the apparent activation energy. also, these surfactants refer the preferential dissolution of iron from the alloy.