铝箔交流扩面腐蚀中SO_4^(2-)缓蚀机理的研究

INHIBITION MECHANISM OF SO_4^(2-) IN AC ETCHING OF Al-FOIL

测试了高纯电子铝箔 (以下简称铝箔 )在 2mol/LHCl和 2mol/LHCl+0 5mol/LH2 SO4溶液中三角波动电位激励时的电流响应曲线 ,用Daubechies2小波对所测得的电流响应曲线进行了时频分解 ,研究了SO2 -4在铝箔交流扩面电蚀工程中的缓蚀机理 .提出了铝箔在含Cl-溶液中点蚀时的氧空位侵蚀机理模型 ,该模型指出在一定的酸度条件下 ,在侵蚀膜表面形成的正电荷集中点是Cl-与SO2 -4发生特性吸附的原因 ;Cl-在侵蚀膜内的主要传输途径是存在于侵蚀膜内微晶晶界上的氧空位链 ;进入侵蚀膜内的SO2 -4在强场作用下发生离解 ,离解出的O2 -与侵蚀膜内的氧空位作用 ,致使氧空位湮灭 ,切断了Cl-在侵蚀膜内的传输途径 ,同时由于这种作用调整了Cl-在侵蚀膜内传输的网络结构 ,增加了蚀孔内新生蚀孔的萌生机率 。

Pitting corrosion behavior of high purity Al-foil in 2 mol/L HCl and 2 mol/L HCl+0.5 mol/L H 2SO 4 solution was investigated by cyclic triangular wave potentiodynamic method.The current signals were analyzed by Daubechies2 wavelet transform yielded time-frequency information.The inhibition mechanism of SO 2- 4 in AC etching of high purity Al-foil was discussed.A new model of oxygen vacancy mechanism for high purity aluminum pitting corrosion indicated that if the pH of the solution is less than the isoelectronic point,the oxide film on aluminum will acquire positive charges,this positive charges are caused by the characteristic adsorption of Cl - and SO 2- 4.Cl - transport through the oxide film by means of oxygen vacancies.O 2- dissociate from SO 2- 4 under the function of local electric field captured the oxygen vacancy,decreased the concentration of oxygen vacancies,modified the transport network of Cl - in the oxide film.As the result,the probability of new pit initiation increased,this is high performance of inhibition of SO 2- 4 acted in AC etching of Al-foil.