20.500.12556/DiRROS-24177 Influence of surface pretreatments on composition, structure and corrosion performance of zirconium conversion coating applied to AA7075-T6 The effect of chemical pretreatment of aluminium alloy 7075-T6 on the composition, morphology, and structure of zirconium conversion coatings (ZrCC) was investigated. Chemical pretreatments included: (i) alkaline etching and desmutting using commercial reagents, (ii) alkaline etching using sodium hydroxide, (iii) acidic etching using nitric acid, (iv) desmutting using a commercial reagent and boiling in deionised water, and (v) alkaline etching and desmutting using nitric acid. ZrCCs were deposited at room temperature from a 200 ppm H2ZrF6 solution of pH 4.8. A commercial SurTec® coating containing zirconium and trivalent chromium was used as a benchmark. The electrochemical behaviour was evaluated using potentiodynamic polarisation measurements and electrochemical impedance spectroscopy conducted over a minimum of 5 days and up to 15 days in 0.1 M NaCl. Corrosion resistance was further assessed through immersion testing. Microstructural characterisation was performed using scanning electron microscopy with energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. The SurTec® pretreatment of AA7075-T6 activated the self-sealing of the subsequently deposited ZrCC, about 40 nm thick, which exhibited the highest degree of compactness and uniformity. This study showed a significant impact of surface chemical pretreatment on the microstructural and protective properties of ZrCCs deposited on 7075 alloy. surface pretreatment etching desmutting predobdelava površin true false true IOP Publishing Združeno kraljestvo Angleški jezik Slovenski jezik © 2025 The Author(s). Neznano 2025-11-18 12:48:48 2025-11-18 12:48:48 2025-11-19 03:42:42 0000-00-00 00:00:00 2025 0 0 Nasl. z nasl. zaslona; Opis vira z dne 14. 11. 2025; str. [1-24] no. 11, [article no.] 111501 Vol. 172 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2025-08-20 2025-10-28 2025-11-10 546 1945-7111 10.1149/1945-7111/ae18fd 257239811 https://iopscience.iop.org/article/10.1149/1945-7111/ae18fd 1 8e3c4118-c474-11f0-94a7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=35984 RAZ_Sekularac_Gavrilo_2025.pdf RAZ_Sekularac_Gavrilo_2025.pdf 1 63BCD871AD4DE25F6009E0F5DEB2453C f30173541df8d732d74a5938006fcf98bebb4c9c0fb42f1b082e26452074d007 10606b13-c475-11f0-94a7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=35985 Institut Jožef Stefan 0 0 0