تاثير جوانه زا AL-TI-B و كادميم بر رفتار الكتروشيميايي آند فداشونده آلومينيومي

Aluminum sacrificial anode is an important anode which is used vastly by industries. Due to its availability and also its high driving potential , is used for cathodic protection of structures in sea water. Pure aluminum is not used because of forming a passive layer on its surface and causing reduction in anode efficiency Therefore some elements such as , indium , mercury , tin , galium are added to anode to perevent passivation. Also other elements such as manganes , magnesium , titanium , cadmium and bismut are added to anodes for the improvement of its electrochemical properties. The aim of this research was to determine the effect of titanium and cadmium added together and also individually. Tests were carried out to determine anode efficiency, polarization behaviour, open and closed circuit potential, corrosion rate. Metallographic analysis, EDAX, SEM and XRD were carried out on samples with different concentrations of titanium and cadmium. The results show that titanium causes homogeneous microstructure and increases the anode efficiency and shifts the potential to more negative values. It was revealed that cadmium reduces adhesion of corrosion products and causes the elimination of passive region in polarization curve and shifts the potential to more negative values. Addition of 0.02% cadmium and 0.02% titanium (optimum position) to aluminum anode results in increasing anode efficiency from 84% to 94% and reducing the corrosion rate from 113 mpy to 45 mpy and shifting the potential from -1084 mV to -1283 mV (SCE).