%0 Journal Article
%T Schiff Bases of Triethylenetetramine as Corrosion Inhibitors of Zinc in Hydrochloric Acid
%A Shah
%A M.D.
%A Patel
%A A.S.
%A Mudaliar
%A G.V.
%A Shah
%A N.K.
%J Portugaliae Electrochimica Acta
%D 2011
%I Sociedade Portuguesa de Electroqu¨ªmica
%X the performance of triethylenetetramine-tribenzylidene (tttb) and triethylenetetramine-trisalicylidene (ttts) as corrosion inhibitors for zinc in hydrochloric acid is investigated. at lower concentrations, both inhibitors accelerate the attack but inhibit corrosion at higher concentrations, e.g., 96-100% with 1.0% concentration in 0.5 m and 1.0 m hcl. the efficiency of tttb decreases while that of ttts remains almost constant (¡Ý 99.7%) up to 120 minutes and in the temperature range 35 - 65 oc. the activation energies are higher in inhibited than in plain acid with both inhibitors. the free energy of adsorption (¦Ägads) and heat of adsorption (qads) are negative, which suggests that there is spontaneous adsorption on metal surface, and from the values of (¦Ägads) and (qads), the values of entropy of adsorption (¦Äsads) were calculated. galvanostatic polarization shows that corrosion is under mixed control with predominance of the cathodic part. in uninhibited 1.0 m hcl, complete cathodic protection is achieved at a current density of 4.2224 adm-2, but in presence of these inhibitors, much lower current densities are required. plot of log (¦È/1-¦È) versus log cinh gives a straight line, suggesting that inhibitors cover both the anodic and cathodic regions through general adsorption following langmuir isotherm. the mechanism of inhibition has been proposed.
%K corrosion
%K zinc
%K hydrochloric acid
%K inhibitor.
%U http://www.scielo.gpeari.mctes.pt/scielo.php?script=sci_abstract&pid=S0872-19042011000200004&lng=en&nrm=iso&tlng=en