(1. 北京科技大學(xué) 新材料技術(shù)研究院，北京 100083；
2. 南京鋼鐵股份有限公司，南京 211500；
3. 江蘇省高端鋼鐵材料重點(diǎn)實(shí)驗(yàn)室，南京 211500)
摘 要: 在青島工業(yè)海洋大氣環(huán)境中對(duì)硫酸及硼硫酸陽(yáng)極氧化處理的6061鋁合金進(jìn)行5 a的長(zhǎng)周期大氣暴曬實(shí)驗(yàn)，通過(guò)表面截面形貌觀察、質(zhì)量損失分析、腐蝕產(chǎn)物分析、力學(xué)性能檢測(cè)和斷口分析等方法，研究?jī)煞N陽(yáng)極氧化處理對(duì)6061鋁合金長(zhǎng)期腐蝕行為的影響規(guī)律及機(jī)理。結(jié)果表明：經(jīng)5 a大氣暴曬試驗(yàn)后，表面陽(yáng)極氧化處理能顯著降低6061鋁合金的平均腐蝕速率及力學(xué)性能損失，且硫酸陽(yáng)極氧化的效果更明顯；與裸材相比，硫酸和硼硫酸陽(yáng)極氧化后5 a暴曬試驗(yàn)的平均腐蝕速率分別下降了70.2%和45.4%，屈服強(qiáng)度損失率分別下降了69.5%和11.0%，伸長(zhǎng)率損失率分別下降了71.8%和41.0%。青島工業(yè)海洋大氣環(huán)境中高濃度的Cl-會(huì)對(duì)6061鋁合金表面的氧化膜侵蝕破壞，穿透氧化膜引起點(diǎn)蝕。當(dāng)點(diǎn)蝕發(fā)生在晶界處時(shí)，引發(fā)了晶間腐蝕；環(huán)境中的硫化物伴隨著腐蝕介質(zhì)可深入到晶界區(qū)域，加劇了沿晶裂紋的擴(kuò)展。陽(yáng)極氧化膜對(duì)Cl-的侵蝕有較強(qiáng)的阻擋作用，且硫酸陽(yáng)極氧化膜的阻擋作用更好，能有效地抑制晶間腐蝕的萌生和擴(kuò)展，進(jìn)而減小了6061鋁合金強(qiáng)度及塑性的損失，使得硫酸陽(yáng)極化6061鋁合金具有較好的強(qiáng)度和伸長(zhǎng)率。
關(guān)鍵字: 工業(yè)海洋大氣環(huán)境；陽(yáng)極氧化6061鋁合金；點(diǎn)蝕；晶間腐蝕；力學(xué)性能
（1. Institution of Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China;
2. Nanjing Iron and Steel Co., Ltd., Nanjing 211500, China;
3. Jiangsu Key Laboratory for Premium Steel Material, Nanjing 211500, China）
Abstract:The outdoor exposure tests of anodized 6061 aluminum alloy in sulfuric acid and boron-sulfuric acid were carried in industrial-marine atmospheric environment at Qingdao for five years. The effects of two different anodizing methods on the corrosion behavior and mechanism of 6061 aluminum alloy were investigated by means of the surface and cross-section morphology observation, mass loss method, the corrosion products analysis, mechanical properties testing and fracture analysis. The results show that the average corrosion rates of the anodized alloy in sulfuric acid and boron-sulfuric acid decrease by 70.2% and 45.4% after five-year exposure in the industry-marine atmospheric environments, respectively, compared to the naked alloy. The loss of yield strength decrease by 69.5% and 11.0%, and the loss of elongation decrease by 71.8% and 41.0%. Thus, the anodic treatment weakened corrosion and the effect of sulfuric acid anodizing is much better than for the boron-sulfuric acid anodizing. The high concentration of chloride ions in the industry-marine atmosphere in Qingdao plays an important role in the destruction of the oxide films and in inducing the pitting corrosion. Due to the pitting on the grain boundaries, the intergranular corrosion initiated. The sulfide in the atmosphere can penetrate into the grain boundary region along with the corrosive medium, which aggravate the propagation of the intergranular corrosion. The anodized film has an effective hindrance for chloride ions penetrating to the matrix, and the effect of anodizing in sulfuric acid is better, which can effectively inhibit the initiation and propagation of intergranular corrosion, thereby reduce the loss of strength and plasticity of 6061 aluminum alloys.
Key words: industrial-marine atmospheric environment; anodized 6061 aluminum alloy; pitting corrosion; intergranular corrosion; mechanical properties
