电解液pH对7075铝合金表面微弧氧化膜层腐蚀性能影响研究  

Properties of Micro-Arc Oxides of 7075 Aluminum Alloys Prepared with Different pH

作　　者：江海霞 陈俐蔓 韩东 周波 刘刚 胡小刚 邱龙时 Jiang Haixia;Chen Liman;Han Dong;Zhou Bo;Liu Gang;Hu Xiaogang;Qiu Longshi(Xi'an Rare Metal Materials Institute Co.,Ltd.,Xi'an 710016,China)

机构地区：[1]西安稀有金属材料研究院有限公司,陕西西安710016

出　　处：《稀有金属》2024年第12期1692-1701,共10页Chinese Journal of Rare Metals

基　　金：国家自然科学基金青年基金项目(52101099,52201021);陕西省自然科学基金青年项目(2023-JC-QN-0583);陕西省一般工业项目(2024GX-YBXM-343);陕西省青年科技新星项目(2023KJXX-082);陕西省秦创原高层次人才项目(QCYRCXM-2022-263,QCYRCXM-2022-153,QCYRCXM-2023-029)资助。

摘　　要：7075铝合金在海洋环境下耐腐蚀性能的不足限制了其在国防工业领域的应用。微弧氧化(MAO)技术是提升铝合金表面性能的有效途径之一,电解液p H是影响微弧氧化膜层微观结构、力学性能及物化性能的关键参量。采用微弧氧化技术在7075铝合金表面制备膜层,通过调节KOH含量改变电解液p H,探究不同p H对微弧氧化膜层微观结构、厚度和耐腐蚀性能的影响。结果表明:微弧氧化处理能够显著改善7075铝合金的抗腐蚀性能。随电解液p H增加,微弧氧化过程中击穿电压降低,膜层孔隙率呈先降低后增加的趋势,膜层厚度变化趋势则与之相反,样品耐蚀性能提高。当电解液p H为12.7时,膜层孔隙率达到最低值4.63%,微弧氧化膜层在3.5%Na Cl(质量分数)溶液中表现出最佳的耐腐蚀性能,其自腐蚀电位为-0.6 V,自腐蚀电流为4.74×10-^(7)A·cm^(-2),极化电阻值为18.7×10^(3)Ω·cm^(2);腐蚀速率较7075铝合金降低约一个量级,大小为0.0056 mm·a^(-1)。7075 Al alloy is a kind of alloy material with high strength and excellent wear resistance,which is widely used in aerospace,automotive and other fields.In recent years,the application of 7075 aluminum alloy in marine vessels has gradually increased with the proposal of marine energy strategy.However,despite its good mechanical properties and strength,its corrosion resistance in marine environment is unsatisfactory and susceptible to corrosion,which seriously affects its safety and service life,and limits its large-scale application in the field of 7075 Al alloy in the field of marine engineering,national defense industry and others.In order to solve this problem,researchers are constantly searching for ways to improve the alloy,such as alloy surface coating technology,alloy formulation optimization,etc.,to improve the corrosion resistance of 7075 Al alloy in marine environment.Micro arc oxidation(MAO)technology is one of the effective ways to improve the surface properties of aluminum alloys by combining the electrolyte and appropriate electrical parameters so that the metal on the surface of the substrate interacts with the electrolyte solution,forming a ceramic film layer on the surface of the substrate,which is dominated by the metal oxides of the substrate.This technique can significantly improve the surface hardness,wear resistance,corrosion resistance and other properties of the material,which is of great importance in improving the overall performance of aluminum alloys.The pH of the electrolyte is a key parameter affecting the microstructure,mechanical properties and physical and chemical properties of the micro-arc oxidation film layer.Different pH leads to changes in the composition and structure of the film layer,which in turn affects its hardness,wear and corrosion resistance,and other properties.Therefore,in the micro-arc oxidation process,proper control of the pH of the electrolyte is essential to achieve the desired performance of the film layer.The film layer was prepared on the surface of 7075 a

关 键 词：7075铝合金 PH 微弧氧化(MAO) 耐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]