微量Ga对电容器阳极用铝箔组织及比电容的影响

采用X射线衍射定量检测含微量Ga高压电解电容器阳极用退火箔的立方织构，用金相显微镜及扫描电镜观察其显微组织，用图像分析软件分析腐蚀箔的腐蚀结构，研究了微量Ga对组织结构、腐蚀结构及比电容的影响.结果表明:Ga的质量分数由05×10-6提高至116×10-6时，铝箔的立方织构的体积分数略微下降，但在520V的比电容却由0662μF/cm2增加到0706μF/cm2；当Ga的质量分数增加至214×10-6时，显微组织及织构变化不明显，但比电容下降至0693μF/cm2.这是因为适当添加微量Ga能促进电化学腐蚀发孔，增加箔的表面积，提高其比电容；但Ga的质量分数高于116×10-6时，将增加箔的并孔数量，减少其表面积，导致比电容下降.

Effects of Trace Ga on Microstructure and Specific Capacitance of Aluminum Foils Used for Capacitor Anodes

The cubic texture of the annealed high purity aluminum foils with trace Ga used for the anode of high voltage electrolytic capacitors was quantitatively characterized by X ray diffractometer (XRD). The microstructures of their hot rolled plates and final annealed foils were observed by optical microscope(OM) and scanning electron microscope (SEM). The corrosion structures of the etched foils were quantitatively analyzed with image analysis software. Based on the above experiments the effects of the mass fraction of trace Ga on the microstructures and the corrosion structure as well as the specific capacitance were investigated. The results showed that with the mass fraction of Ga increasing from 05×10-6 to 116×10-6， the volume fraction of cubic texture in the foils decreased slightly， but the specific capacitance of the foils measured at 520V increased from 0662μF/cm2 to 0706μF/cm2. Further increasing the mass fraction of Ga to 214×10-6 did not affect the microstructure and the fraction of the cubic texture， but the specific capacitance dropped to 0693μF/cm2. Adding trace Ga promoted the electrochemical pitting and resulted in the enlargement of the specific surface area of the foil and the improvement of the specific capacitance. However when the mass fraction of Ga was higher than 116×10-6， obvious pit merging occurred， the specific surface area of the foil reduced and the specific capacitance decreased.