| At present, the sacrificial anode materials used for the protection of iron and steel, which are based of aluminum, zinc and magnesium alloy. The performance of sacrificial anode is determined by it's chemical constitution and structure. The Al -based anode with low density, high current efficiency, much power generated, moderate potential applied to iron and steel, is a rapidly developed new sacrificial anode material. Zn-based anode with high density, less power generated, low potential, applied to iron and steel, ease to polarize at high temperature, is usually used in the environment of low electrical resistance. Mg-based anode with low current efficiency, high potential applied to iron and steel (ease to over-protect), is only used in soil environment of high electrical resistance.In this experimental according to data from salt water test of normal temperature and results of performance test, through comprehensive analysis, the premium content range of alloy of the sacrificial materials is determined. The electrochemical performance of sacrificial anode material is tested and the function of element in the alloy is analyzed. In Al alloy, the cadmium added can improve the uniform distribution of Zn, decrease segregation of Zn, between the corrosion condition of anode, but if the content of Cd is high, It will segregate new phase, produce the effect of" over-activation ", increase self-corrosion, usually the content of Cd is 0.01 percent. Mg(0.5~0.4 percent) can notably increase it's current efficiency, especially there is little Sn, the influence is more obvious, because Sn and Mg have good matching function. The content of Sn is usually 0.01-0.1 percent. The most important effect of Si is to better the cast performance of Al alloy, but have detrimental effect on the performance of anti-corrosion and weld of the alloy.By orthogonal testing method, the premium element content of Al-Zn-In-Cd is determined. The results of test are as follows, when the content of Al-3.5Zn-0.02In-0.01Cd, the every index of electrochemical performance of the sacrificial anode material can reach or overpass national standard. The product of corrosion is easy to remove, the surface dissolve uniformly, and the potential is much more negative and stable, and current density at the range of 0~20mA. There is passivity. The anode is kept in active condition, the distribution of structure is uniform, due to the good matching of Zn and Cd, the surface dissolve uniformly, the produce of corrosion is easy to remove, so it is the most ideal constitution of sacrificial material.By experimenting, the Al-Zn-In-Sn-Re and Al-Zn-In-Mg-Re sacrificial anode material having high current efficiency, good uniformity of distribution of metallurgical phase and the more much content of Re, the higher start potential and current efficiency, and the more uniform of surface dissolve. So, they are ideal sacrificial anode material.In the following anode material Al-4Zn-0.03In-0.03Ti-lMg, Al-7Zn-0.1Sn-0.03Ti-lMg, Al-3Zn-0.03In-0.015Cd-l.25Mn, and Al-7Zn-0.1Sn-0.015Cd, the most important function of Ti is to make the structure of solid solution refine. Al forms TiAh with added Ti, which have high meting point and fine crystalline, can act as crystalline core to refine. The structure of Al alloy, and make the resolve of anode uniform.In addition, the small amount Ti added, can prevent the heat check during casting, decrease the corrosion between crystalline in the anode. Sn melts in the Al to form solid solution, with the degree of solvent at about 0.03 percent, and enters the surface oxide film of Al in the form of SnO, and destroys it's passivity, decrease the potential of Al.Two kinds of anode material, Zn-Al-Cd and Zn-Al-Mn, are explored in the experiment. The content of Al is not suited too high, only so, Al and Cd is matching infection well. Al and Cd in the alloy make the crystalline of Zn alloy fine, inhibit the influence of impurity, and accordingly improve the performance of Zn anode. Mn active metal, increases current efficiency. This kind o...
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