Raman Spectrum Analysis of Chromate Conversion Coating on AA 3003 Aluminum Alloy
1. College of New Energy, China University of Petroleum (East China), Qingdao 266580, China;
2. China Special Equipment Inspection and Research Institute, Beijing 100029, China;
3. The Boiler & Pressure Vessel Safety Inspection Institute of Henan Province, Zhengzhou 450016, China
Abstract Trivalent chromium conversion coatings were the most promising alternative to replace chromate conversion coatings. The microstructure, components and chemical valence of trivalent chromium conversion coating on aluminum alloy AA3003 were investigated by scanning electron microscope, energy dispersive X-ray spectrometer and high resolution Raman spectroscopy. Results revealed that trivalent chromium conversion coated AA 3003 alloy was a contact film with elements of Cr, Zr, F and O. The characteristic Raman vibration positions for hexa- and trivalent chromium components (CrO42- and Cr2O3) were at 866 and 536 cm-1. There was no chromate component in the fresh trivalent chromium conversion coating, but the high power of laser source induced the production of chromate.
