镁合金电子结构与腐蚀特性研究  

Electronic structure and corrosion character of Mg alloys

作　　者：刘贵立[1] 

机构地区：[1]沈阳工业大学建筑工程学院,沈阳110023

出　　处：《物理学报》2010年第4期2708-2713,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50671069);辽宁省教育厅科学研究计划(批准号:2008511;20060807;2007T165);沈阳市科技计划基金(批准号:1072026100)资助的课题~~

摘　　要：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 Mg alloy was calculated with the recursion method.The result shows that the density of states of Mg in grain is similar to that on the surface of Mg alloy,but it is obviously different when O or O,H atoms exist on the surface of Mg alloys.This indicates Mg has similar properties whether in grain or on surface,but the properties of Mg change apparently after oxygen or hydrogen atom permeated in the surface layer of Mg alloy.Al,Y or La atom diffuses from grain to the surface and segregates there,because each the doped atom embedding energy of Al,Y or La atom on the surface is lower than that in grain.The affinity energy of Al-O,Y-O,La-O,Mg-O,Mg-O-H is negative,so they can form compound.Because the affinity energy of Mg-O-H is lower than that of Mg-O,Mg（OH）2 is more stable than MgO.In the early stage of oxidation,oxygen combined with Mg,Al,Y or La forming oxide.When Mg alloy is in corrosive medium,MgO reacts with H2O forming Mg（OH）2.Al2O3,（Y,La）2O3 and Mg（OH）2 can protect Mg alloys from corrosion and improve corrosion resistance.

关 键 词：电子结构 MG合金 腐蚀特性 

分 类 号：TG111.1[金属学及工艺—物理冶金] TG146.22[金属学及工艺—金属学]