Manganese is easy to combine with harmful impurity elements, thus eliminating the effect of Fe on the corrosion resistance of the alloy, so that the corrosion rate is greatly reduced. Manganese and iron Mn - Fe compound formation, due to the effect of gravity compound precipitation in the bottom of the crucible, the rest is not form chemical compounds of Fe is surrounded by manganese, thereby greatly reducing the feeling now is its effect on the corrosion resistance of alloy, in the very is all don't know the increase current efficiency, to reduce Fe anode in the harm of Fe: The proportion of Mn should be less than 0.032.
Fe: The solubility of Fe in the anode is very small. During the crystallization process of the alloy liquid, Fe precipitates on the grain boundary to form a galvanic pair with magnesium. Due to the large potential difference between Fe and Mg, it is easy to generate current, which aggravates the anodic autolysis tendency, accelerates the corrosion rate of the alloy, and reduces the current efficiency of the anode.
Ni: It forms a compound Mg2Ni with magnesium, which is distributed on the grain boundary in the form of a network. The corrosion of magnesium anode will be aggravated and the current efficiency will be reduced.
Cu: Forms Mg2Cu, or MgCu2, with magnesium, and distributes at grain boundaries, which increases the self-corrosion of the magnesium anode together and reduces the current efficiency of the anode.
Si: The solubility in magnesium is very small, and in many cases, it is very green and magnesium form. Mg2Si is distributed in the grain boundary and inside the crystal. When it coexists with Fe, the autolysis tendency of magnesium alloy is increased, and the current efficiency of the anode is reduced.
Al: Aluminum in high potential is a harmful element, which can form cathode phase with magnesium and accelerate the corrosion rate. The presence of aluminum also reduces the solubility of manganese in magnesium.