20.500.12556/DiRROS-22057 Complementary corrosion protection of cast AlSi7Mg0.3 alloy using Zr-Cr conversion and polyacrylic/siloxane-silica multilayer coatings Aluminium cast alloy AlSi7Mg0.3 is a lightweight metal commonly used in automotive, aeronautical and mechanical applications. It has good corrosion resistance but, under harsh operative conditions, would benefit from additional protection. In this study, a corrosion-protective multilayer coating system for AlSi7Mg0.3 based on hexafluoro-zirconated trivalent chromium coating (Zr-CrCC) and polyacrylic/siloxane-silica (PEHA-SS) coating was developed. The Zr-CrCC was formed by immersion of the substrate in a commercial conversion bath (SurTec® 650). PEHA-SS synthesis was based on organic precursors (2-ethylhexyl acrylate and [3-(methacryloyloxy)propyl]trimethoxysilane) and an inorganic precursor, tetraethyl orthosilicate. After deposition on AlSi7Mg0.3, each coating was first characterised individually, followed by the analysis of the multilayer using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The adhesion of the coatings was evaluated with a cross-hatch cut test. The corrosion studies in sodium chloride solution using electrochemical impedance spectroscopy and salt spray testing showed that the multilayer system is superior to individual Zr-CrCC and PEHA-SS coatings. After 4 months in 0.1 M NaCl, the multilayer-coated samples exhibited the impedance at 10 mHz in the range of GΩ cm2, while scribed samples withstood the corrosion attack in a salt spray chamber for one week. Thus, albeit only about 100 nm thick, the Zr-CrCC deposited between the substrate and a 9-micrometre thick barrier sol-gel PEHA-SS coating acts as an active corrosion protection interlayer and contributes to the overall protectiveness of the multilayer system. corrosion-protective aluminium material korozija zaščita aluminij true false true Springer Nature Švica Angleški jezik Slovenski jezik © The Author(s) 2024 Neznano 2025-04-17 13:10:47 2025-04-17 13:10:48 2025-10-24 03:50:27 0000-00-00 00:00:00 2024 0 0 Nasl. z nasl. zaslona; Opis vira z dne 4. 6. 2024; str. 1-16 Vol. 8, article no. 58 May 2024 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2023-10-21 2024-04-19 2024-05-28 620.1/.2 2397-2106 10.1038/s41529-024-00467-5 197709827 https://www.nature.com/articles/s41529-024-00467-5 1 a0b54227-1b7c-11f0-963a-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=31861 RAZ_Rodic_Peter_2024.pdf RAZ_Rodic_Peter_2024.pdf 1 0BCF588C68798D2157938A955BFFBE43 cb8618540078e87039efd8c758552dabe3d9d75fca119aff762f131ef0953e7d 5513b54e-1b7d-11f0-963a-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=31862 Institut Jožef Stefan 0 0 0