| In all structural metal and alloy material, the density of the magnesium is the lowest. Compared with other metal structural materials, the intensity and rigidity of magnesium and alloy are higher, it is strong to reduce and shake damping , electromagnetic shielding and ability to resist radiation, cut and process of good performancly, easy to retrieve the advantage of utilizing etc. a series of more , have extremely important using value and wide application prospect in the automobile, electron , electric apparatus, traffic, spaceflight, aviation, and military industrial field of national defence, it is the third kind of metal structural material developed following steel and aluminium alloy, praised as the green project material in the 21st century. One that is with a lot of metal mineral resources is exhausted day by day, the magnesium but paid attention to day by day with its abundant advantage of resource, especially the light quantization technology of the structure and demand of the issue on environmental protection, have promoted the fast development of magnesium alloy industry greatly.However, the electric potential of the electrode is the lowest in the metal material that the magnesium and alloy use actually at present, so anti-corrosion performance is very bad, will corrode quickly even if preserve in the atmospheric environment, so it is necessary to carry on the inoculation to it. It is the surface treatment is best at present, such as chemistry converting coating such methods as the membrane , anodization, a little arc oxidizing , electroplating , chemistry plating or hot spraying of positive pole ,etc. Among them, the result of use of transforming the membrane of the chromate is best, but the environmental pollution is the most serious, have already completely forbidden using in such developed countries of the industrial technology as the United States and Japan ,etc. at present; Other methods have not made a breakthrough yet.
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