PCB-HASL电路板在NaHSO_3/Na_2SO_3溶液中的腐蚀电化学行为  

ELECTROCHEMICAL CORROSION BEHAVIOR OF PCB-HASL IN NaHSO_3/Na_2SO_3 SOLUTION

作　　者：丁康康 肖葵[1] 邹士文[1] 董超芳[1] 赵瑞涛[1] 李晓刚[1] 

机构地区：[1]北京科技大学腐蚀与防护中心,北京100083

出　　处：《金属学报》2014年第10期1269-1278,共10页Acta Metallurgica Sinica

基　　金：国家自然科学基金资助项目51271032~~

摘　　要：采用电化学阻抗谱(EIS)和扫描Kelvin探针技术(SKP)研究了热风整平无铅喷锡处理印制电路板(PCB-HASL)在模拟电解质0.1 mol/LNaHSO3以及不同pH值的0.1 mol/LNaHSO3/Na2SO3溶液中的腐蚀行为与机理,探讨了浸泡时间和pH值对其腐蚀机理转变的影响,通过OM,SEM结合EDS对PCB-HASL表面上腐蚀产物形核和扩展行为进行了观察和分析.结果表明,PCB-HASL试样在酸性NaHSO3/Na2SO3溶液体系中的腐蚀形式类似点蚀,浸泡前期腐蚀坑加速扩展,腐蚀产物主要为Sn的氧化物和硫酸盐.NaHSO3溶液能够活化PCB-HASL试样表面,且腐蚀坑形核仅发生在浸泡初期.而在中性或碱性NaHSO3/Na2SO3溶液体系中,PCB-HASL试样表面腐蚀坑形成受到抑制,电解质溶液通过氧化膜向电极界面的传输过程限制了电极反应速率.With the innovation of electronic technology,integration and miniaturization become the future developing direction of printed circuit board（PCB）.Meanwhile,the corrosion problems of PCB also stand out more clearly,and even trace amounts of corrosion products will have a serious impact on the reliability of PCB.Under the actual condition for use,like sulfur-containing industrial environment,due to the diurnal temperature variations or/and the temperature field fluctuations for PCB itself,condensation phenomenon is likely to occur.Furthermore,as a result of the moisture absorption effect of granular deposit or supersaturated humidity,a layer of electrolyte solution will be formed on the surface of PCB,causing electrochemical corrosion.In this work,electrochemical impedance spectroscopy（EIS） and scanning Kelvin probe（SKP） techniques were used to study the corrosion behavior and mechanism of hot air solder leveling printed circuit boards（PCB-HASL） in a simulated electrolyte 0.1 mol/L NaHSO3 and 0.1 mol/L NaHSO3/Na2SO3 solutions with different pH values,and the influences of immersion time and pH value on the change of corrosion mechanism were discussed.Meanwhile,with the aids of OM,SEM combined with EDS,the nucleation and propagation processes of corrosion products on the surface of PCB-HASL were observed and analyzed.SEM and EDS results showed that the corrosion behavior of PCB-HASL in acid simulation solution was similar to pitting corrosion,and the corrosion pits were in a state of accelerated expansion at the early immersion stage.The corrosion products mainly consisted of oxides and sulfates of Sn.EIS and SKP analysis indicated that the PCB-HASL surface could be activated by NaHSO3 solution and pitting nucleation process only occurred at the early immersion stage.In the neutral or alkaline solution system of NaHSO3/Na2SO3,pitting corrosion couldn＇t occur,and the transmission of the electrolyte to the electrode interface through the oxide film was the control step of the corrosion reaction.

关 键 词：印制电路板 热风整平无铅喷锡 NaHSO3溶液 电化学腐蚀 扫描KELVIN探针 

分 类 号：TG174.4[金属学及工艺—金属表面处理]