Plasma electrolytic oxidation (PEO) of 7075 Al alloy was carried out in silicate base electrolyte containing 200 nm diameter α-Al2O3 particles for producing composite coatings. The process was performed under a soft-sparking regime using a pulsed bipolar signal with several concentrations of α-Al2O3 particles. It was found that the incorporation of α-Al2O3 particles into the coating did not significantly alter the thickness and roughness of the coating. However, the α-Al2O3 particles were detected on surface of the composite coatings. Corrosion tests showed significant improvement in corrosion performance of the composite coatings due to the efficient pore blocking provided by α-Al2O3 particles, which enhances the barrier performance of both inner and outer layers of the coatings. However, the long-term EIS measurements showed that the performance of composite coatings becomes close to that of particle-free coating after 56 days of immersion in chloride containing solution. Tribocorrosion tests showed that adding 3 g·l−1 of α-Al2O3 particles to the electrolyte bath decreased the lost wear volume of the resulted coating from 30 to 10 mm3 (×10−3). Higher α-Al2O3 particles concentration (i.e. 7 g·l−1) showed detrimental effect on both corrosion and tribocorrosion performance of the coating.

Ghafaripoor, M., Raeissi, K., Santamaria, M., Hakimizad, A. (2018). The corrosion and tribocorrosion resistance of PEO composite coatings containing α-Al2O3 particles on 7075 Al alloy. SURFACE & COATINGS TECHNOLOGY, 349, 470-479 [10.1016/j.surfcoat.2018.06.027].

The corrosion and tribocorrosion resistance of PEO composite coatings containing α-Al2O3 particles on 7075 Al alloy

Santamaria, Monica
;
2018-01-01

Abstract

Plasma electrolytic oxidation (PEO) of 7075 Al alloy was carried out in silicate base electrolyte containing 200 nm diameter α-Al2O3 particles for producing composite coatings. The process was performed under a soft-sparking regime using a pulsed bipolar signal with several concentrations of α-Al2O3 particles. It was found that the incorporation of α-Al2O3 particles into the coating did not significantly alter the thickness and roughness of the coating. However, the α-Al2O3 particles were detected on surface of the composite coatings. Corrosion tests showed significant improvement in corrosion performance of the composite coatings due to the efficient pore blocking provided by α-Al2O3 particles, which enhances the barrier performance of both inner and outer layers of the coatings. However, the long-term EIS measurements showed that the performance of composite coatings becomes close to that of particle-free coating after 56 days of immersion in chloride containing solution. Tribocorrosion tests showed that adding 3 g·l−1 of α-Al2O3 particles to the electrolyte bath decreased the lost wear volume of the resulted coating from 30 to 10 mm3 (×10−3). Higher α-Al2O3 particles concentration (i.e. 7 g·l−1) showed detrimental effect on both corrosion and tribocorrosion performance of the coating.
2018
Settore ING-IND/23 - Chimica Fisica Applicata
Ghafaripoor, M., Raeissi, K., Santamaria, M., Hakimizad, A. (2018). The corrosion and tribocorrosion resistance of PEO composite coatings containing α-Al2O3 particles on 7075 Al alloy. SURFACE & COATINGS TECHNOLOGY, 349, 470-479 [10.1016/j.surfcoat.2018.06.027].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/339637
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