铝电解电容器高压电子箔点蚀机理的研究

采用极化曲线和场发射扫描电镜等方法,研究了铝电解电容器高压电子箔在高温强酸性溶液中的点蚀机理。结果表明:在开路状态下铝光箔在硫酸盐酸发孔溶液中可以产生点蚀,测到自腐蚀电位就是点蚀电位;形成隧道孔后,阳极极化曲线出现点蚀电位,且点蚀过电位与隧道孔长度之间存在线性关系。根据点蚀的微电池模型及其在阳极极化下微电池的腐蚀极化图,提出产生上述现象的原因是阳极极化时带孔铝箔的表面由阴极向阳极转变,其转变的临界点即所测到的点蚀电位。

Pitting Mechanism for Aluminum Electrolytic Capacitor High Voltage Foil

Pitting mechanism for aluminum electrolytic capacitor high voltage foil in strong acidic solution was investigated by means of polarization curve and scanning electron microscopy(SEM).The results indicate that pitting can generate on the surface of Al foil under open circuit,and its corrosion potential measured is pitting potential.Pitting potential appears on the polarization curves of Al foil with tunnel pits,and there is linear relationship between the pitting over-potential and the tunnel length.According to micro-cell model of pitting and the corrosion polarization diagrams of micro-cell,it is thought that the surface of Al foil with tunnel pits transforms from cathode to anode during anodic polarization,and the critical point of the transformation is the measured pitting potential.