纳米金属Cr在酸性介质中腐蚀电化学行为

为探究纳米材料的腐蚀机理,采用机械合金化通过热压制备了纳米金属Cr,并与常规尺寸金属Cr对比研究了其在酸性介质中的腐蚀性能.结果表明:当晶粒尺寸细化到纳米级后,金属Cr腐蚀电流密度增大,耐蚀性能下降;随着酸度的增加,常规尺寸和纳米尺寸金属Cr腐蚀电流密度加大,耐蚀性能下降.两种尺寸金属Cr在中性Na2SO4介质中均出现钝化现象,但常规尺寸金属Cr的钝化区间较宽;常规尺寸金属Cr在加入H+后,钝化减弱,而纳米尺寸金属Cr在加入H+后,钝化现象消失;两种尺寸Cr的交流阻抗谱均呈单容抗弧特征,对纳米材料的应用具有重要意义.

Studies on the corrosion elecrochemical behavior of nanocrystalline Cr in acidic media

In order to study corrosion mechanisms of nanocrystalline materials,nanocrystalline metal Cr is prepared by mechanical alloying through hot-pressing processes.Its corrosion mechanism and corrosion resistances in acidic media is thus investigated as compared with the corresponding coarse-grained Cr.Results show that with the increment of acid concentration,the corrosion current densities increase and therefore the corrosion resistances decrease.After the grain size is refined,the corrosion current densities of nanocrystalline Cr are larger than those of the corresponding coarse grained materials.This indicates that the corrosion resistances decrease when the grain size is refined.Two kinds of grain size metal Cr produce passive phenomena,but they become weaker with the increment of acid concentration.The electrochemical impedance spectroscopy(EIS) of the two alloys in acidic media is composed of single capacitive loop.This study is of significance for nanocrystalline materials applications.