碱蚀对铝合金常温硬质阳极氧化膜性能的影响

Effect of Alkali Etching Process on Properties of Room Temperature Hard Anodized Film of Aluminum Alloy

为改进铝合金的性能,优化阳极氧化工艺,以硫酸为电解液,采用常温硬质阳极氧化法在6063铝合金表面制备氧化膜,采用扫描电镜、EDS测试、电化学测试、盐雾试验、硬度测试、粗糙度测试研究膜层性能及碱蚀工艺对膜层性能的影响。结果表明:氧化温度10℃、氧化时间3 000 s条件下,硬质阳极氧化膜呈高低不平、粗糙的多孔结构,其耐蚀性能、物理性能相比6063铝合金基体有很大提升。经过碱蚀处理的硬质阳极氧化膜的自腐蚀电位为-0.826 V,自腐蚀电流为3.892×10^(-6) A,盐雾试验360 h时未出现腐蚀点,耐腐蚀性能较好,维氏硬度达到446 HV,粗糙度Ra为0.380μm,厚度为18.86μm,附着力表现较好。相比未经碱蚀所得的膜层,碱蚀后膜层的耐蚀性能较好,膜层的硬度、表面粗糙度等物理性能较好。

In order to improve the performance of aluminum alloy and optimize the anodizing process,with using sulfuric acid as the electrolyte,the normal temperature hard anodizing method was used to prepare an oxide film on the surface of 6063 aluminum alloy.Subsequently,the film performance and the effect of the alkali etching process on the film performance were studied by scanning electron microscopy,EDS testing,electrochemical testing,salt spray testing,hardness testing,and roughness testing.Results showed that under the conditions of oxidation temperature of 10℃ and oxidation time of 3000 s,the as-obtained hard anodized film had an uneven and rough porous structure,and its corrosion resistance and physical properties were greatly improved compared to the 6063 aluminum alloy substrate.The self-corrosion potential of the hard anodized film after alkali etching treatment was-0.826 V,and the self-corrosion current was 3.892×10^(-6) A.No corrosion points appeared in the salt spray test for 360 h,and the corrosion resistance was good.Meanwhile,the film possessed the Vickers hardness reaches of 446 HV,the roughness Ra of 0.380μm,the thickness of 18.86μm,and the excellent adhesion performance.Compared with the film obtained without alkali etching,the film after alkali etching had the better corrosion resistance and physical properties such as hardness and surface roughness.