| As effective and environmentally friendly methods to replace chromateconversion coatings, Ce-based conversion coatings (CeCCs) and sol–gel derivedorganosilane films have been widely studied by many researchers.Ce-basedconversion coatings have excellent ability of scratch resistance, durability andadhesion to the metallic substrate. To our interesting, the most special feature of thiskind of coatings is its ability of ‘‘self-heal’’. However, the major problem of thismethod is the wide-range existence of cracks. Organosilane films are very dense,which can act as a physical barrier to delay the access of the aggressive species tometallic substrate.In this paper, Ce-Silane composite coatings were successfully prepared on1060Alumium. The the optimal parameters of cerium-silane composite coating wasdetermined by orthogonal experiment: CeCl37H2O:40g/L; BETSPT:3g/L; H2O2:60ml/L; pH:4.0; temperature:35℃; time:10min.The surface morphology, chemical composition, element distribution,electrochemical properties and hydrophobicity of cerium-silane composite coatingunder optimum conditions were studied by use of SEM, EDS, polarization curves, CAtester and other methods, and made comparison with the pure cerium conversioncoating. Study concluded that the composite film is more uniform and compact thanthe pure cerium conversion coating, it almost has no obvious cracks, it makes up forthe the shortage and improve the performance overall the film.Further, the conductivity of the silane hydrolysis, the film morphology and thepolarization curve were measured to study the influence of pH and temperature ofsilane hydrolysis on the formation of film. Studies have shown that, pH andtemperature has a certain influence on the preparation of the film, when the pH isgreater, it promotes the hydrolysis reaction of the silane, or it promotes thepolycondensation reaction; Increase in temperature can improve the deposition rateand improve the phase structure of the coating, but when the temperature is too high,the test will be more difficulty than before and it is not conducive to control, onlymake pH is3.0, the temperature is35℃can prepare cerium-silane composite coating which has excellent performance. |
