Effects of trace lead on the etching of aluminum foils for high voltage electrolytic capacitors

The effects of the addition of lead on the morphology, microstructure and capacitance of etched aluminum foils for high voltage electrolytic capacitors are investigated here. The results show that the etched tunnels had square cross sections about 1.3 m per side. The inner tunnel sidewalls had a rough corrugated texture with regular ripples with a periodic interval of about 0.12 m. The addition of lead to high purity aluminum foils can effectively increase the number of grains and etched holes, which enhances the etching of the surface. However, the cubic textured fraction will be reduced. The experiments showed that the maximum capacitance was obtained when the incremental addition of lead reached 0.3 ppm.