ALTERNATIVY CHROMáTOVáNÍ V PROTIKOROZNÍ OCHRANĚ GALVANICKY VYLOUČENÝCH ZINKOVÝCH POVLAKŮ

VERNER, P., CHRaST , V., KRAHULA, K., ZMRZLÝ, M., CERŇANSKÝ, M., HOUDKOVa, J., VORLICEK, V.: Chromate alternatives in zinc galvanized steel surface treatment. Acta univ. agric. et silvic. Mendel. Brun., 2006, LIV, No. 1, pp. 135–144 Surface treatment of zinc galvanized steel is carried out usually using chromate based baths. These baths are used for improvement of the corrosion resistance and enhancement of the chemical adhesion of organic coatings. Anticorrosive effects of the chromium conversion coatings were not completely ex ceeded yet by another kind of passivation. Toxicity of Cr VI is a basic problem of chromate conversion coats. This paper presents the main results and conclusions of experimental study on zinc conversion layers based on vanadates, using a good Cr VI bath as reference. Anticorrosive mechanisms were compared by the corrosion tests in saline cabinet. Inhibition effects were characterized by scanning electron microscopy, by X-ray dispersive spectrometry (EDS) associated X-ray diffraction (XRD), X-ray photo electron spectroscopy (XPS) and Raman spectroscopy. zinc galvanized steel, chromate free alternative passivation baths, salt spray, EDS, XRD, XPS, Raman spectroscopy