稀土Ce和Nd对AZ31镁合金耐蚀性能的影响  

Effects of Rare Earth Elements on the Corrosion Property of AZ31 Magnesium Alloy

作　　者：余琨[1] 黎文献[1] 王日初[1] 巢国辉[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《材料保护》2007年第11期6-9,共4页Materials Protection

摘　　要：采用盐雾腐蚀和动电位扫描研究了稀土元素Ce、Nd对AZ31镁合金耐腐蚀性能的影响。采用数码相机、金相显微镜和扫描电镜观察及定量金相分析系统测量分析了样品的腐蚀程度,并采用恒电位仪测量了动电位扫描极化曲线。结果表明,盐雾腐蚀试验中,合金试样腐蚀面积百分数随时间延长呈直线上升,添加稀土Ce和Nd后腐蚀速率降低50%以上。在电化学试验中,添加稀土后合金腐蚀电流密度降低了1/3～1/2。稀土可以起到提高α(Mg)固溶体耐蚀性能的作用,还可以形成含稀土的第二相并使AZ31合金中的β(Mg17Al12)相均匀分布,发挥其阻碍腐蚀的作用,从而最终提高AZ31镁合金的耐蚀性能。The rare earth cerium and neodymium were added in AZ31 magnesium alloy to improve its corrosion resistance. The corrosion behaviors of such alloy were measured through salt spray test and potentiodynamic polarization test. The surface of specimens was observed by using Nikon990 digital camera, Polyvar-MET optical microscope with VSM2000 quantitative analysis system and JEOL scanning electron microscopy. The potentiodynamic polarization curve was measured by using Solartron 1287 poten-tiostat system with a scanning rate of 5 mV/s. The data were collected and analyzed using Corrware and Corrview software. The results showed that the corrosion rate of alloys with Ce or Nd ad-dition decreased about a half in the salt spray test. And the corrosion electrical current also decreased to 0. 12 μA/cm2 and 0. 10 μA/cm2, being less than half of the compared AZ31 alloy (0. 30 μA/cm2). The rare earth Ce and Nd could improve the corrosion resistance of solid solution α(Mg) and make the second phase (3 (Mg17Al12) compound dispread more uniformly, so the corrosion resistance of AZ31 alloy was increased due to the addition of the rare earth element.

关 键 词：AZ31镁合金 稀土 耐腐蚀性能 盐雾腐蚀 动电位扫描 

分 类 号：TG174.3[金属学及工艺—金属表面处理]