Property Study of Chromate Conversion Coatings Formed by Fast-Repair in Out Field
Fast repair of damaged parts of outfield equipment can maintain the functionality and lifespan of equipment in service.The damage and repair sites with the chromate conversion coating on the surface of AA 7B04 aluminum alloy,in-cluding the surface microstructure,chemical composition,electrochemical performance,and acidic salt spray perfor-mance,are compared and analyzed.Results indicate that the in-house chromate solution can effectively repair scratched samples.A dense film is formed at the scratched site after repair,and the main components include elements such as Cr,F,O,K,et.al;comparative analyses of Raman spectroscopy results showed that there is a significant chromate,CrO42-(855 cm-1),at the same site;electrochemical impedance spectroscopy at 10-2 Hz proves that the impedance film value of the repaired sample is 5.09×105 Ω·cm-2,which is 5 times higher than the scratch sample;polarization curve shows that corrosion current density of the repaired sample is 10-5.5 A·cm-2,which is an order of magnitude lower than that of the scratch sample;in addition,the acidic salt spray period of the repaired sample exceeded 336 hours without any corrosion points on the surface of the sample.The surface salt spray rating reached level 10,and the corrosion rate characterized by the weight loss method is one order of magnitude lower than that of the scratch sample.
万方数据
维普
