碱蚀对铝合金表面性能的影响  

Effect of alkaline etching on surface properties of aluminum alloy

作　　者：宗朋德 周琦[1] 金建东 贺春林[2] ZONG Pengde;ZHOU Qi;JIN Jiandong;HE Chunlin(School of Environmental and Chemical Engineering,Shenyang Ligong University,Shenyang 110159,China;Liaoning Provincial Key Laboratory of Advanced Materials,Shenyang University,Shenyang 110044,China)

机构地区：[1]沈阳理工大学环境与化学工程学院,辽宁沈阳110159 [2]沈阳大学辽宁省先进材料制备技术重点实验室,辽宁沈阳110044

出　　处：《电镀与涂饰》2024年第4期87-93,共7页Electroplating & Finishing

基　　金：辽宁省重点研发计划项目(2020JH2/10100011)。

摘　　要：[目的]氢氧化钠碱蚀对铝合金的外观和表面性能影响极大。[方法]利用铜离子置换法检测铝合金自然氧化膜的去除效果,用三维形貌仪考察样品的微观形貌和粗糙度,用光泽度仪测量样品表面光泽。[结果]在10℃以上采用50g/L NaOH溶液或在20℃用质量浓度20g/L以上的NaOH溶液碱蚀2min,均可完全去除6061铝合金表面的自然氧化膜,但不能消除车抛划痕。随着碱蚀温度的升高,铝合金析氢越来越剧烈。经碱蚀的铝合金在除灰后光泽明显增大,但相对于除油未碱蚀的试样,光泽都下降,在高于30℃下碱蚀会大大降低铝合金表面的光泽。在10~30 g/L的NaOH溶液中碱蚀并除灰后,铝合金表面的光泽优于采用高NaOH浓度下碱蚀的试样。铝合金经过NaOH碱蚀后表面粗糙度增大,20℃和30℃碱蚀后的表面较平整,在30~50℃范围内随着碱蚀温度上升,表面粗糙度Ra增大。碱蚀后铝合金表面挂灰的颜色随着温度的升高而加深,40℃以上的碱蚀会导致铝合金表面发生点蚀。[结论]铝合金的光泽和表面粗糙度受氢氧化钠碱蚀的影响很大,应注意碱蚀液温度和浓度的选择。[Introduction]The alkaline etching with sodium hydroxide has a great effect on the appearance and surface properties of aluminum alloy.[Method]The removal of natural oxide film from an aluminum alloy surface was inspected by copper ion replacement method.The micromorphology and surface roughness of the specimens were examined by using a 3D profilometer,and their glossiness was measured with glossmeter.[Result]The natural oxide film on the surface of 6061 aluminum alloy could be completely removed after 2 minutes of immersion in a 50 g/L NaOH solution at temperature above 10℃ or in a NaOH solution of more than 20 g/L at 20℃.However,the scratches caused by lathe polishing could not be eliminated.The hydrogen evolution reaction of aluminum alloy became more and more intense during alkaline etching with the increasing of temperature.The glossiness of the alkali-etched aluminum alloy was increased significantly after desmutting,but lower than the degreased specimen prior to alkaline etching.Alkaline etching above 30℃ greatly reduced the glossiness of aluminum alloy surface.The specimens etched in 10-30 g/L NaOH solution after desmutting had higher glossiness than that etched with higher NaOH concentration.The surface roughness of aluminum alloy was increased after alkaline etching with sodium hydroxide.The surface smoothness was relatively high after alkaline etching at 20℃ or 30℃.The surface roughness Ra was increased with the increasing of alkaline etching temperature in the range of 30 to 50℃.The color of smut on the surface of alkali-etched aluminum alloy became darker with the increasing of etching temperature.Alkaline etching at above 40℃ resulted in pitting corrosion of aluminum alloy.[Conclusion]Alkaline etching with sodium hydroxide has great impact on the gloss and roughness of aluminum alloy surface.The temperature and NaOH concentration should be determined reasonably.

关 键 词：铝合金 碱蚀 氢氧化钠 微观形貌 光泽 粗糙度 

分 类 号：TG176[金属学及工艺—金属表面处理] TG146.21[金属学及工艺—金属学]