微弧氧化处理对6061铝合金电偶腐蚀防护

6061 Aluminium Alloy Protected from Galvanic Corrosion by Micro-arc Oxidation Treatment

目的提高船舶上铝合金的耐蚀性能。方法使用双极性脉冲电源对6061铝合金进行微弧氧化处理,并使用环氧树脂进行封孔,通过电化学测试、扫描电子显微镜(SEM)、能谱仪(EDS)、浸泡腐蚀试验和电偶腐蚀试验等方法,对膜层的表面形貌、截面形貌、物相组成和耐蚀性能进行测试。结果制备的6061铝合金微弧氧化膜层厚度约为40μm,致密均匀。在240h浸泡试验后,仍具有较强的耐蚀性,与316L不锈钢耦合的电流密度从约47μA/cm^(2)下降到20μA/cm^(2)左右,对6061铝合金的耐蚀性有显著提升。封孔处理后,浸泡腐蚀240h,未发现明显腐蚀,电偶电流进一步下降到11μA/cm^(2)。结论对6061铝合金进行微弧氧化处理,可以有效提高其耐蚀性能,对电偶腐蚀有较好的抑制作用,封孔处理则可以进一步提高铝合金的耐蚀性能。

The work aims to improve the corrosion resistance of aluminum alloys on ships.The 6061 aluminium alloy was subject to micro-arc oxidation treatment with a bipolar pulsed power supply and was sealed with epoxy resin.The surface morphology,cross-section morphology,physical phase composition,and corrosion resistance of the resulting film layer were tested through electrochemical testing,SEM observation,EDS,immersion corrosion experiments,and galvanic coupling corrosion tests.The micro-arc oxidation film prepared on the 6061 aluminium alloy had a thickness of approximately 40μm,and it was both dense and uniform.After a 240-hour immersion experiment,the corrosion resistance of the material remained strong.The coupling current density of 316L stainless steel decreased from approximately 47μA/cm^(2) to about 20μA/cm^(2),and the corrosion resistance of 6061 aluminium alloy was significantly improved.No obvious corrosion was found after hole sealing treatment followed by the 240-hour immersion and the electric coupling current decreased to 11μA/cm^(2).The corrosion resistance of the 6061 aluminium alloy can be effectively improved through micro-arc oxidation treatment which also has good inhibition effect on galvanic corrosion.Additionally,the corrosion resistance of the aluminium alloy can be further improved through hole sealing treatment.