(南昌航空大學(xué) 輕合金加工科學(xué)與技術(shù)國防重點(diǎn)學(xué)科實(shí)驗(yàn)室，南昌 330063)
摘 要: 將鋁合金硼酸−硫酸陽極氧化膜浸入鈰鹽轉(zhuǎn)化液中進(jìn)行封閉。采用交流阻抗譜技術(shù)研究各封閉參數(shù)對 氧化膜耐蝕性的影響，比較了不同方法封閉的氧化膜的耐蝕性差異。結(jié)果表明：將硼酸−硫酸陽極氧化試樣浸入30 ℃的鈰鹽轉(zhuǎn)化液(5 g/L Ce(NO3)3+0.5% H2O2)中處理30 min后，多孔層電阻Rp大幅增加，且腐蝕電流密度降低1個(gè)數(shù)量級，耐蝕性明顯優(yōu)于沸水封閉氧化膜的，也稍優(yōu)于稀鉻酸封閉氧化膜的耐蝕性。結(jié)合EDS分析表明：鈰鹽轉(zhuǎn)化封閉后硼酸−硫酸陽極氧化膜的外表面形成了一層完整致密的鈰鹽轉(zhuǎn)化膜，多孔層內(nèi)也充滿了鈰的封閉產(chǎn)物，二者的協(xié)同作用幾乎完全封住了硼酸−硫酸陽極氧化膜的孔隙，從而有效地提高了氧化膜的耐蝕性。
關(guān)鍵字: 硼酸−硫酸陽極氧化膜；鈰鹽轉(zhuǎn)化封閉；交流阻抗譜；多孔層；耐蝕性
boric-sulfuric acid anodic film of aluminum alloy
（National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology Institute,
Nanchang Hangkong University, Nanchang 330063, China）
Abstract:The boric-sulfuric acid anodic (BSAA) film on aluminum alloy was sealed by cerium salt conversion solution. The effects of sealing parameters on the corrosion resistance of BSAA film were researched through electrochemical impedance spectroscopy (EIS), while the corrosion resistance of anodic films sealed by different methods was studied. It is found that the resistance of porous layer increases significantly, the corrosion resistance is improved greatly and the corrosion current density is reduced by about 1 order of magnitude when the BSAA film was immersed in the cerium conversion solution (5 g/L Ce(NO3)3+0.5% H2O2) at 30 ℃ for 30 min. Besides, the corrosion resistance of BSAA film sealed by this method is much better than that by boiling water sealing, and also slightly superior to that of the dilute CrO3 solution sealing. Combined with EDS analysis results, it is indicated that a intact, compact cerium conversion film forms on the outside surface of BSAA film, and the porous layer is also filled with sealing products when the BSAA film is sealed by cerium salt conversion solution. The synergism of the two actions almost completely sealed the pores of BSAA film, thereby effectively improving the corrosion resistance of anodic film.
Key words: boric-sulfuric acid anodic film; cerium salt conversion sealing; EIS; porous layer; corrosion resistance
