2026-08-22T00:37:46Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/1184822025-03-05T09:46:24Zcom_20.500.14352_14col_20.500.14352_16

00925njm 22002777a 4500 dc Moreno Turiegano, Lara author Mohedano Sánchez, Marta author Arrabal Durán, Raúl author Matykina, Endzhe author 2024-03-02 Bioactive plasma electrolytic oxidation (PEO) coatings were developed on a wrought Mg0.5Zn0.2Ca alloy using a transparent electrolyte for easy maintenance and waste disposal, compared to a conventional suspension-based solution. Treatment times of 300, 600, and 900 s were evaluated for their effects on coating morphology, composition, and corrosion resistance. A short-time electrochemical impedance spectroscopy (EIS) screening was utilized to identify coatings with optimal corrosion protection. To assess the degradation rate and corrosion mechanisms, hydrogen evolution was monitored under pH-controlled quasi-in vivo conditions over extended immersion periods. Coating thickness increased by only 3% from 300 to 900 s of treatment (13 and 18 µm, respectively), with pore bands formed near the barrier layer at 900 s. The short-term EIS screening revealed that the coatings produced at 600 and 900 s were less protective and consistent than those at 300 s due to the presence of pore bands, which increased permeability. Hydrogen evolution measurements during 5 days of immersion at pH 7.4 indicated a tenfold higher degradation rate of the PEO-coated alloy compared to the bare substrate. Therefore, none of the PEO coatings provided effective corrosion protection after 24 h of immersion, which is attributed to crack formation at the PEO/corrosion products interface. This highlights the importance of crevices in the corrosion of Mg-Zn-Ca alloys. The presence of ZnO exacerbates the corrosion of magnesium in crevice areas. 2079-6412 10.3390/coatings14030309 https://hdl.handle.net/20.500.14352/118482 https://doi.org/10.3390/coatings14030309 https://www.mdpi.com/2079-6412/14/3/309 Data: Degradation rate control issues of PEO-coated wrought Mg0.5Zn0.2Ca alloy