بررسي تاثير ناخالصي هاي اكسيدي بر خواص الكتروشيميايي آندهاي فداشونده آلومينيمي

The Effect of Oxide Impurities on the leetrochemical Properties of Aluminum Sacrificial Anodes

The presence of anode impurities in varied forms in the final product of aluminum alloys castings affects their physical, chemical and mechanical properties. The electrochemical properties of sacrificial anodes produced through casting are also affected by these impurities. To investigate the effect of these oxide impurities on Al-Zn-In electrochemical properties, three methods of increasing the height of pouring, increasing retrogression, and stirring the melt were employed to determine and specify the amount of reduction in electrochemical properties (capacity current, potential and efficiency) by entering oxide impurities into the melt. The presence of oxide crusts resulting from the melt turbulence during pouring can encourage nucleation of blowholes by providing a non-wetted surface and have an extra effect on the capacity current. The presence of floating oxides in the melt imprisoned in the piece after solidification is another factor in the reduction of the capacity current. To investigate the effect of pouring height on the functioning of anode, a melt with a temperature of 750°C was poured into the mold from the heights of 30, 60, 120, 240, 360, and, 480 millimeters and after each stage a sample was taken for subsequent tests. The effect of retrogression was studied by employing the amounts of 15, 30, 45, and 60 percent by weight from the alloy fillings .The stirring of the melt within 3, 2,3, 4, and 5 minutes while entering surface oxides into the melt was effective in the reduction of the electrochemical properties. Hie results showed that the three mentioned factors had negative effects on the electrochemical features of the anodes..