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采用递归法计算了镁合金电子结构.研究发现Mg的态密度在晶内与表面接近,当表面有氧或氢氧时态密度形状改变很大,因此Mg在晶内、表面性质是接近的,但当合金表面渗透氧或氢时,合金性质有明显变化.Al,Y,La三种元素在晶体表面的掺杂原子镶嵌能均低于各自在晶内的掺杂原子镶嵌能,Al,Y,La从晶内向晶体表面扩散、并在合金表面偏聚.Al-O,Y-O,La-O,Mg-O及Mg-O-H间的亲和能均为负数,这些原子间存在亲和力,可以在合金中相互作用形成化合物.由于Mg-O-H间的亲和能远低于Mg-O的亲和能,因此Mg(OH)2比MgO更稳定.氧化初期氧与Mg,Al,Y,La等生成氧化物,当合金与腐蚀介质接触时,MgO与腐蚀介质中的水发生反应生成Mg(OH)2.Al2O3,(Y,La)2O3及Mg(OH)2能对合金起到保护作用,提高合金的耐腐蚀性能.
The electronic structure of magnesium alloy was calculated by recursion method. It was found that the density of state of Mg is close to the surface in the crystal. When the surface is oxygen or hydrogen, the shape of the density of state changes greatly. Therefore, However, when the alloy surface is infiltrated with oxygen or hydrogen, the properties of the alloy are obviously changed.The doping atoms of Al, Y and La on the crystal surface are lower than those of the doping atoms of Al, Y, Y , La diffuses from the inside of the crystal to the crystal surface and segregates on the surface of the alloy.The affinity between Al-O, YO, La-O, Mg-O and Mg-OH are all negative and the affinity between these atoms can be found in The interaction between Mg-OH and MgO is more stable than that of MgO because the affinity between Mg-OH is much lower than that of Mg-O. (MgO) and Mg (OH) 2 can react with water in the corrosive medium to form Mg (OH) 2. When the alloy is in contact with the corrosive medium, Improve the corrosion resistance of the alloy.