摘要
用液相还原法制备纳米粉末并通过真空热压制备了纳米块体Cu-Ag合金,并与粉末冶金法制备的常规尺寸Cu-Ag合金对比研究了它们在中性Na2SO4介质中的腐蚀电化学行为。结果表明:随着晶粒尺寸的降低,合金的腐蚀电位负移,表明腐蚀倾向增大;随着晶粒尺寸的降低,合金的腐蚀电流密度增加,表明腐蚀速度加快;两种尺寸的Cu-Ag合金在Na2SO4介质中均没有出现钝化;随着晶粒尺寸的降低,容抗弧曲率半径逐渐减小,电荷传递电阻逐渐减小,表明腐蚀速度加快;两种尺寸的Cu-Ag合金在Na2SO4介质中的交流阻抗谱由单容抗弧组成;在Na2SO4介质中,纳米尺寸Cu-Ag合金的腐蚀为较均匀的腐蚀,而常规尺寸Cu-Ag合金的腐蚀为不均匀腐蚀。
Cu-Ag alloy powders in nano-size were obtained by aqueous reducing method and the nanocrystalline Cu-Ag bulk alloy was prepared through hot pressing with the temperature at 650 ℃ in vacuum.The corrosion electrochemical behavior of the alloy was compared in Na2SO4 media with the coarse grained Cu-Ag bulk alloy prepared by conventional powder metallurgy.The results of corrosion potential curves showed that corrosion potential decreased and therefore corrosion tendency aggravated when grain size was refined.The results of potentiodynamic polarization curves（PPC） showed that corrosion current densities of alloy increased and therefore corrosion rates become faster when grain size was refined.Passivation was unable to appear with increment of corrosion potential in Na2SO4 media.The results of electrochemical impedance spectroscopy（EIS） showed that charge transfer resistance decreased and therefore corrosion rates became faster when grain size was refined.The corrosion processes of Cu-Ag alloy with different grain size were controlled by the electrochemical reactions.The corrosion of nanocrystalline Cu-Ag alloy was uniform and the corrosion of coarse grained CuAg alloy was non-uniform.
出处
《沈阳师范大学学报（自然科学版）》
CAS
2011年第2期245-248,共4页
Journal of Shenyang Normal University:Natural Science Edition
基金
辽宁省教育厅创新团队资助项目(2007T166)
关键词
液相还原法
纳米晶
CU-AG合金
腐蚀电化学
aqueous reducing method
nanocrystalline
Cu-Ag alloy
corrosion electrochemistry
