Experimental Research On The Surface Modification Of Aluminum And Its Alloys In Alkaline Electrolyte

Among the Aluminum surface modification technology, the widest range ofwhich comes as aluminum anodizing technology, from the early1920s, the worldbegan the study of anodic oxidation, now, and the technology has been deep intoamong the people’s production and life. But throughout the entire process conditionsof anodizing technology, found that most anodizing process are carried out in acidicelectrolyte conditions and the information and research on alkaline electrolyteanodized is little, so the paper studies the laws of anodized aluminum under theelectrolyte conditions.5052aluminum alloy and NaOH was selected as a tool anode and particularelectrolyte solution in the paper. The tooling test was designed, the four main factorsof the process parameters such as the voltage, time, the gap between electrodes andelectrolyte concentration are analyzed and determined, thus, a four-factors and threelevels of orthogonal test program anodized tests was designed. After the preparationof the anodic film, the technology of apparent observation, SEM, EDS and XRD wereused to analyze the apparent morphology, elemental content and chemical state, phasecomposition of the prepared film. Besides, the layer hardness, film layer and substratematerial binding force, corrosion resistance, such as comprehensive performance afterdetermination of anodic oxidation in alkaline electrolyte membrane were measuredthrough self-designed bending test and corrosion test video display with the use ofVickers hardness tester and automatic coating adhesion scratch instrument, throughthe whole optimization, the optimal process parameters are obtained.The test results show that the Vickers hardness the coating layer which wasmeasured by video display of the Vickers hardness was about380HV or so; Thescratch test and bending test showed that the binding properties of the anodic oxidefilm and the substrate material was fine; The corrosion test showed that the corrosionresistance of aluminum alloy matrix through anodic oxidation treatment has been significantly improved. In the orthogonal experiment, the anodic film which wasgenerated in the eighth test conditions was uniform, dark gray, and had no obviouswhite patches, black spots, flow marks, etc. The microscopic observation showed thefilm had a more uniform pore rules; film hardness were able to reach the highest440HV, membrane-binding properties and corrosion resistance were fine whichjointly determine the optimum process conditions for the experimental were voltage25V, the gap between poles0.1mm, time40min, the electrolyte concentration of5%.