纳米晶Cu-50Ag合金在酸性溶液中腐蚀行为研究

Corrosion Behavior of Nanocrystalline Bulk Cu-50Ag Alloys in Acidic Solutions

与粉末冶金法(PM)制备的常规尺寸合金对比,研究了通过热压液相还原法(LPR)和机械合金化法(MA)合成的Cu-50Ag合金粉末制备的块体纳米晶Cu-50Ag合金在酸性溶液中的腐蚀行为。结果表明:在Na_2SO_4溶液中加入H_2SO_4后,3种合金的腐蚀速度均加快。随着H_2SO_4浓度的增加,PMCu-50Ag和LPRCu-50Ag合金的腐蚀速度均未发生明显变化,而MACu-50Ag合金的腐蚀速度则加快。在Na_2SO_4溶液中,3种合金均未出现钝化现象,随着H_2SO_4的加入,合金出现了钝化现象。3种合金的腐蚀速率按PMCu-50Ag,LPRCu-50Ag和MACu-50Ag合金的顺序增加,其中LPRCu-50Ag合金的腐蚀速度略大于PMCu-50Ag合金,但明显小于MACu-50Ag合金。

The corrosion behavior of two nanocrystalline bulk Cu-50 Ag alloys prepared from hot pressing powders which were synthesized by liquid phase reduction or mechanical alloying was investigated in acidic solutions as compared with the corresponding coarse grained Cu-50 Ag alloy.Results show that the corrosion rates of the three alloys become faster after H2SO4 is added to Na2SO4 solutions.The corrosion rates of PMCu-50 Ag and LPRCu-50 Ag alloys remain unchanged,but those of MACu-50 Ag alloy become faster with the increment of H2SO4 solution concentrations.In Na2SO4 solutions,there are no passivation phenomena for three Cu-50 Ag alloys.On the contrary,there are passivation phenomena after H2SO4 is added to Na2SO4 solutions.The corrosion rates of three Cu-50 Ag alloys increase in the order of PMCu-50 Ag,LPRCu-50 Ag and MACu-50 Ag alloys.The rates of LPRCu-50 Ag alloy are slightly higher than those of PMCu-50 Ag alloy,but are evidently lower than those of MACu-50 Ag alloy.In Na2SO4 solutions,EIS of three alloys are composed of single capacitive loops.There are diffusion tails after H2SO4 is added to Na2SO4 solutions.This indicates the corrosion processes are controlled by diffusion.