[en] Magnesium alloys are considered for industrial applications due to their low density and high specific strength. However, their high corrosion susceptibility remains a limitation, necessitating the development of effective surface protection strategies. In this study, AZ31 alloy was modified using hybrid zirconium-silicon sol-gel coatings (ZTP), plasma electrolytic oxidation (PEO) layers produced under arc (PEO-AR) and soft (PEO-SR) regimes, and combined PEO/ZTP duplex systems. The coatings were characterized in terms of morphology, composition, and mechanical behaviour. FTIR analysis confirmed the formation of an inorganic-organic hybrid network based on Zr–O–Si, Si–O–Si and Zr–O–Zr linkages, whereas rheological measurements revealed constant behaviour with ageing time (∼11.8 mPa·s), favouring controlled pore infiltration. SEM/EDS analyses confirmed the formation of porous PEO layers and the deposition of a uniform sol-gel coating on AZ31, while the duplex systems displayed different structural architectures. The PEO-AR/ZTP coating reached 11.41 μm, reflecting extensive sol-gel penetration into the large, open pores of the oxide layer. While, the PEO-SR/ZTP coating exhibited a thicker duplex structure (28.4 μm), but sol-gel infiltration remained largely superficial due to the finer and more compact pore network of the PEO layer. Tribological testing revealed that the PEO-AR/ZTP coating achieved the lowest coefficient of friction (∼0.35) and superior wear resistance, whereas the PEO-SR/ZTP coating exhibited partial layer detachment and progressive degradation during sliding. These show that sol-gel infiltration depth and PEO pore architecture are key to the mechanical integrity and durability of duplex coatings, providing a framework for the design of hybrid protective systems for magnesium alloys.
Research center :
CRIM - Ingénierie des matériaux
Disciplines :
Materials science & engineering
Author, co-author :
Moreno, Lara ; Materials Science Department, University of Mons, Mons, Belgium
Mégret, Alexandre ; Université de Mons - UMONS > Faculté Polytechnique > Service de Métallurgie ; Université de Mons - UMONS > Faculté Polytechnique > Service de Science des Matériaux
Paint, Yoann ; Université de Mons - UMONS > Unités externes > Materia Nova ASBL ; Materia Nova Research Center, Mons, Belgium
Olivier, Marie-Georges; Materials Science Department, University of Mons, Mons, Belgium ; Materia Nova Research Center, Mons, Belgium
Language :
English
Title :
Influence of PEO regime on sol-gel infiltration and performance of hybrid organic-inorganic coatings on AZ31 alloy
R400 - Institut de Recherche en Science et Ingénierie des Matériaux
Funders :
Horizon 2020 Framework Programme Université de Mons
Funding text :
This research has been funded by the Belgian government through the University of Mons (UMONS), as part of the Come to Wallonia (C2W, Horizon 2020 European Union Funding for Research and Innovation) grant programme, which was attributed to Lara Moreno. The C2W grant has been the beneficiary of funding from the European Union's Horizon 2020 research and innovation programme, under the Marie Sk\u0142odowska Curie grant agreement No. 101034383.
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