中文摘要：

用液相还原法制备纳米尺寸Ag-50Ni粉末而后热压制得其纳米块体合金，并与传统粉末冶金法制备的粗晶Ag-50Ni合金对比研究了它们在含Cl^-介质中的腐蚀电化学行为．结果表明：合金粉末平均粒径约为45nm，真空热压后，晶粒有所长大，但仍为纳米尺度；随Cl^-浓度增加，两种尺寸Ag-50Ni合金的腐蚀电流密度均增加，腐蚀速度加快；晶粒尺寸降低后，腐蚀电流密度略有增加，腐蚀速度变快；当极化电位增到某一程度后，两种尺寸Ag-50Ni合金均出现钝化；纳米尺寸Ag-50Ni合金在含0．02mol／LC^l-介质中的交流阻抗谱由双容抗弧组成，其余均由单容抗弧组成，腐蚀受电化学反应控制．

英文摘要：

Precursory alloy powders with an average particle size of about 45nm were obtained by aqueous reducing method firstly and then a nanocrystalline Ag-50Ni bulk alloy was prepared through hot pressing the precursor at 620℃ under a pressure of 58 MPa. The grain sizes of the bulk alloy after hot pressing still remained in nano-size range. The electrochemical corrosion behavior of the nano-alloy was compared in chloride ion containing media with the corresponding coarse grained alloy prepared by conventional powder metallurgy. Corrosion current densities of nanocrystalline and coarse grained Ag-50Ni alloys increase and therefore corrosion rates become faster with the increment of chloride ion concentrations. However, the corrosion current densities of nanocrystalline Ag-50Ni are a little bigger than those of the corresponding coarse grained Ag-50Ni. Ag-50Ni alloys showed passivation behavior in media containing chloride ions with increment of polarization potentials. EIS plot of nanocrystalline Ag-50Ni is composed of single capacitive loop in a medium containing 0.05 mol/L Na2SO4 plus 0. 02 mol/L NaCl,while the others are composed of double capacitive loops. Thus, corrosion processes are controlled by electrochemical reactions.