Zn-3%Al-RE合金机械镀层的电化学腐蚀行为研究

Electrochemical Corrosion Behavior of Zn-3%Al-RE Alloy by Mechanical Plating

采用机械镀工艺,在Zn-3%Al镀层形层过程中添加0-5%的稀土盐,获得几种稀土含量不同的Zn-3%Al-RE合金镀层。利用电化学方法,以pH=5和pH=7的1 mol/L NaCl溶液,0.5 mol/L NaCl＋0.5mol/L Na2SO4溶液,0.5 mol/L Na2SO4溶液为6种腐蚀介质,测定几种镀层在每种腐蚀介质中的电化学参数。结果表明：几种镀层的耐电化学腐蚀性能随着腐蚀介质中Cl^-浓度的增大均有所降低;稀土加入量对镀层耐电化学腐蚀性能的影响不遵循线性关系,加入量为2%和5%时所得镀层的耐电化学腐蚀性能较好。

Zn-3%Al-RE deposited coating was prepared with addition of 0~5% of one RE salt during the Zn-3%Al coating forming process by the process of mechanical zinc plating.And its electrochemical parameters were measured under six media corrosion mediums,1mol/L NaCl,0.5 mol/L NaCl＋0.5 mol/L Na2SO4 and 0.5 mol/L Na2SO4 solutions which is pH=5 and pH=7.The result shows that all the alloy coating＇s corrosion resistance reduces as Cl^-concentration increases;and the relationship between the impact of addition rare earth and the electrochemical corrosion resistant of coating does not follow the linear,the coatings addition 2% and 5% rare earth have better corrosion resistance.