| Summary: | 碩士 === 國防大學中正理工學院 === 應用化學研究所 === 95 === Chromate Conversion Coatings (CCCs) on aluminum alloy were characterized using Electrochemical Impedance Spectroscopy (EIS), Scanning Electron Microsc- opey (SEM), X-ray Photoelectron Spectrometer (XPS) and X-Ray Diffractionary (XRD). Chromium conversion coating use hexafluorozirconate system to form conversion coating contain oxidize chromium and alumina on surface of aluminum alloy, it’s operate parameter contain both temperature and time of accomplish coat, observe the change of parameter to corrosion protection property of trivalent chromium. In measureing,it is obtained that impedance by Electrochemical Impedance Spectroscopy, it’s obtained that surface morphology of conversion coating and compose by Scanning Electron Microscopey, X-ray Photoelectron Spectrometer and X-Ray Diffractionary.
The result shows, it gets well conversion coatings with concentration of trivalent chromium and hexafluorozirconia on 1:1, coat temperature on 40 degree, coat time on 30 sec. In X-Ray Diffractionary, the structure of Chromate Conversion Coatings on aluminum alloy is amorphous situation.
In this study, boric acid and sodium silicate will hinder zirconium element and chromium element deposit on aluminum alloy, and the content of silicon increases among the film of passivation, suspect sodium silicate will deposit in the film, and it do not bounding with trivalent chromium and hexafluorozirconia. Trivalent chromium main key of film, which form trivalent chromium complex on the aluminium alloy.
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