Research On Aluminum Alloy Sacrificial Anode And Its Chemical Conversion Treatment

At present, Aluminium、magnesium and zinc are commonly used as sacrificial anodematerials. Aluminum anode has bigger theoretical electric capacity than magnesium anodeand zinc base anode;and aluminum has moderate driver potential with the iron and steel. It isgood for Aluminum anode in seawater and the environment containing CL-. But the chemicalpropertie of pure aluminium is lively, so it is easy to form a dense oxidation film on thesurface, which makes its potential bigger, and limited its application in sacrificial anodeprotection. Currently, the methods of develop aluminum sacrificial anode materials areusually adding alloying elements in order to limit or prevent aluminum anode surface formingcontinuous compact oxide film, and reduce the potential, promote the anode normal solution.The disadvantage of this method is that making anode process is complicated, large energyconsumption. In fact, the anode still has many problems, such as potential shifts, currentefficiency is low, severely corrode, and dissolving unevenly with high temperature. So theelectrochemical performance of aluminum alloy anode has great potential to develop.In this paper, on the basis of the Al-Zn-In sacrificial anode, by optimizing the alloyelements whose type and content are different, and casting process, obtained the aluminumanode with high capacitance and high current efficiency. At the same time, researched thechemical process on the aluminum anode with the advandage of simple process, less energyconsumption, production fast.The main conclusion as the following:(1) Based on Al-Zn-In anodes, through optimizing the type of alloy elements, itsadjustment and the aluminum anode casting process, successfully developed the aluminumanode, whose actual electric capacity is2700a.h/kg and current efficiency is90.6%.（2）The anode has potential stabilized in normal temperature, and its open circuitvoltage is between1.115~1.105V range, its working voltage range is between1.100to1.090V; the indexes of its performance all can meet or exceed the rules of the GB4948-2002forAl-zinc-in sacrificial anode.(3) Through the single factor experiment and orthogonal experiment optimizing,thebest chemical conversion treatment process is:10g/LKMnO4、9g/L(NH4)6Mo7O24·4H2O、1g/LNaF、4.5g/LNaOH, transformation time is20min, The transformation temperature is 45°C.