最终退火工艺和腐蚀预处理对铝箔发孔性能的影响

Influence of final-annealing and pretreatment before etching on pitting ability of aluminum foils

通过极化曲线测试铝箔的腐蚀电位,结合光学显微镜和扫描电镜等观察铝箔腐蚀发孔后的表面形貌,探讨最终退火工艺和酸碱预处理对高压电子铝箔腐蚀发孔性能的影响规律。结果表明:铝箔在经不同温度(470～560℃)和不同时间(0.5h～4h)的最终退火处理时,当铝箔经500℃,1h退火后,各种有利于发孔的元素扩散到铝箔表层、富集并且均匀分布,此时的发孔效果最好,继续升高退火温度和延长退火时间反而会使发孔变得不均匀;发孔前碱处理能适当减少铝箔表面的氧化层,酸处理则将Cl-引入铝箔表面,酸+碱清洗使铝箔的腐蚀电位降低,促进铝箔的腐蚀发孔,腐蚀后的发孔面积和密度比未经预处理的大,发孔更均匀。

The influence of the final-annealing parameters and pretreatment before etching on the etching ability of the high voltage aluminum foils was investigated.The distribution of pits and the morphological features after etching were observed by metallographic microscopy and scanning electron microscopy.The galvano-chemistry performance of foils was analyzed by using polarization curve.The results show that when the foils are annealed at various temperatures（470-560 ℃） for different annealing times（0.5-4 h）,the best annealing technology is at 500 ℃ for 1 h,which will increase the concentration as well as the distribution homogeneity of the trace elements in the surface layer;it will get bad result if the annealing temperature or the time is increased.The sodium hydroxide pretreatment before pitting can remove the oxide film of the foils,and the hydrochloric acid pretreatment makes Cl- ion enter into the surface of foils.NaOH＋HCl pretreatment reduces the corrosion potential and promotes the pitting of the aluminum foils;the area and density of pit etching on the aluminum surface increase after pretreatment,and the uniformity of pitting also increases significantly.