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采用体视学显微镜和扫描电镜(SEM)结合X射线能谱分析(EDS)研究不同厚度0.1 mol/LNa_2SO_4薄液膜下浸银处理电路板(PCB-ImAg)和无电镀镍金处理电路版(PCB-ENIG)的电化学迁移行为与机理结合交流阻抗谱(EIS)和扫描Kelvin探针技术(SKP)对电偏压作用后PCB金属极板的腐蚀倾向和动力学规律进行分析。研究结果表明,经电偏压作用后,在不同湿度条件下,PCB-ImAg板上银的迁移腐蚀产物数量极为有限,而在高湿度条件下(85%)下,PCB-HASL两电极间同时发现了铜枝晶以及铜/锡的硫酸盐、金属氧化物等沉积物。SKP结果表明,阴极板表面电位明显低于阳极板表面电位,具有较高的腐蚀倾向。建立电偏压作用下PCB电化学迁移腐蚀反应机理模型,并对两种电路板电化学迁移行为差异进行比较。
The effects of different thicknesses of 0.1 mol / L Na 2 SO 4 thin film immersed silver-plated PCB-ImAg and electroless nickel-plated gold processing circuit board (EDS) were studied using stereomicroscope and scanning electron microscope (SEM) PCB-ENIG) electrochemical corrosion behavior and mechanism of the combination of electrochemical impedance spectroscopy (EIS) and scanning Kelvin probe technology (SKP) on the corrosion resistance of PCB metal plates after the tendency and kinetic analysis. The results show that the amount of migration products of silver on PCB-ImAg plate is very limited under different humidity conditions under the condition of electric bias. Under the conditions of high humidity (85%), PCB-HASL electrodes at the same time Copper dendrites and copper / tin sulphates, metal oxides and other deposits were found. The results of SKP show that the surface potential of the cathode plate is obviously lower than the anode plate surface potential and has a high corrosion tendency. Electrochemical migration of PCB under electrochemical bias corrosion electrochemical mechanism model was established, and the differences of electrochemical migration between the two PCBs were compared.