不同工艺制备的纳米晶Ag-25Ni合金在NaCl溶液中的腐蚀性能  

Corrosion Properties of Bulk Nanocrystalline Ag-25Ni Alloys Prepared by Different Processes in NaCl Solution

作　　者：崔田路 顾雪[1] 贾中秋 尹晓桐 曹中秋[1] 张轲[1] CUI Tianlu;GU Xue;JIA Zhongqiu;YIN Xiaotong;CAO Zhongqiu;ZHANG Ke(College of Chemistry and Chemical Engineering,Shenyang Normal University,Shenyang 110034)

机构地区：[1]沈阳师范大学化学与化工学院,沈阳110034

出　　处：《材料导报》2018年第16期2798-2802,2815,共6页Materials Reports

基　　金：国家自然科学基金(51271127);辽宁省自然科学基金指导计划(201602679)

摘　　要：分别通过粉末冶金法(PM)、机械合金化(MA)和液相还原(LPR)法借助于热压制备了一种常规尺寸和两种纳米晶Ag-25Ni块体合金。与相应常规尺寸合金对比,研究了两种不同工艺制备的块体纳米晶Ag-25Ni合金在0.3mol/L NaCl溶液中的腐蚀电化学性能。结果表明,三种不同工艺制备的Ag-25Ni合金的腐蚀电流密度按LPR Ag-25Ni、PM Ag-25Ni和MA Ag-25Ni的顺序降低,它们的交流阻抗谱均由单容抗弧组成,且电荷传递电阻按MA Ag-25Ni、PM Ag-25Ni和LPR Ag-25Ni的顺序降低。与常规尺寸PM Ag-25Ni合金对比,纳米晶LPR Ag-25Ni合金的腐蚀速度增大;相反,纳米晶MA Ag-25Ni合金的腐蚀速度则降低。三种合金形成的钝化膜均为n型半导体,载流子密度大小按LPR Ag-25Ni、PM Ag-25Ni、MA Ag-25Ni的顺序降低,MA Ag-25Ni合金的钝化性能最好,这归因于三种合金显微组织的不同,MA Ag-25Ni合金中晶粒尺寸的降低和组元间固溶度的增加,导致其具有良好的化学稳定性。A coarse-grained and two bulk nanocrystalline Ag-25Ni alloys are obtained by powder metallurgy(PM),liquid phase reduction(LPR)and mechanical alloying(MA)methods by means of hot pressing technique.Their corrosion properties were studied in NaCl solutions.The results show that corrosion current densities of three alloys prepared by different processes decrease in the order of LPR Ag-25Ni,PM Ag-25Ni and MA Ag-25Ni.Their electrochemical impedance spectroscopies consist of one capacitive arc and charge transfer resistances increase in the order of LPR Ag-25Ni,PM Ag-25Ni and MA Ag-25Ni.These show that the corrosion rate of nanocrystalline LPR Ag-25Ni alloy becomes faster,while the corrosion rate of nanocrystalline MA Ag-25Ni alloy becomes slower than that of coarse grained Ag-25Ni alloy.The passivation films were formed in 0.3 mol/L NaCl at 0.9 V potential for three Ag-25Ni alloys,and they all were n type semiconductors.The carrier densities decrease in the order of LPR Ag-25Ni,PM Ag-25Ni and MA Ag-25Ni.The passivation properties of MA Ag-25Ni alloy are the best because of the difference in microstructures among three Ag-25Ni alloys.For MA Ag-25Ni alloy,the decrease in the grain size and increase in the solid solubility contribute to its good chemical stability.

关 键 词：制备工艺 纳米晶 电化学腐蚀 Ag-Ni合金 

分 类 号：TG113.23[金属学及工艺—物理冶金]