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2202 |
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Corrosion resistance of HVOF micro- and nanocermet coatings on AL 7075 |
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Angeliki Lekatou / Department of Materials Science & Engineering, University of Ioannina, Greece Dimitrios Sioulas / University of Ioannina, Dept Mater Sci & Engng, Greece Dimitrios Grimanelis/ Hellenic Aerospace Industry, Greece Alexandros Karantzalis/ University of Ioannina, Dpt Mater Sci & Engng, Greece |
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The present work is part of a wider investigation having as a main goal to evaluate whether HVOF spraying can produce quality coatings on aluminium alloys, in terms of wear and corrosion properties. In this work micro-WC-12% Co, WC-10Co-4Cr and nano- WC-12% Co powders were HVOF sprayed on Al 7075 T6. The coatings have been evaluated in terms of hardness, surface roughness, porosity and wear resistance. The coating corrosion resistances in two different electrolytes (3.5% NaCl and Dilute Harrison?s Solution) at room temperature have been determined by potentiodynamic polarization, chronamperometry, critical pitting temperature determination and Raman Spectroscopy. All the coatings have been subjected to salt spray testing for 40 days. Corrosion tests revealed the superiority of the nano-WC-12% Co coatings in the two solutions, regarding critical electrochemical values and localized corrosion susceptibility. |