Insight into the role of Ce incorporation into energy-efficient flash-PEO films for the corrosion protection of additive-manufactured Al10SiMg

This study reports the development of a thin and energy-efficient plasma electrolytic oxidation (PEO) protective coating on additively manufactured Al10SiMg using an electrolyte composed of Na 3 (P 3 O 6 ) 3 , KOH, Na 2 EDTA and Ce 2 (SO 4 ) 3 . The oxidation period was varied from 100 s to 300 s to understand the correlation between energy consumption and cerium incorporation, as well as its impact on the structural and corrosion resistance of the PEO film. To obtain a mechanistic understanding of the role of cerium, the structural properties before and after immersion in 3.5 wt% NaCl solution were analyzed to determine how cerium functions as an active corrosion inhibitor when incorporated into the PEO layer. The findings revealed successful and uniform cerium incorporation throughout the PEO coating (up to a 200 s oxidation time). The inhibitory effect of Ce was evidenced by the increase in the impedance modulus (Z 0.01 Hz ), which was up to twice as effective as that of PEO without cerium. The Ce-doped PEO protective film, with its intrinsic surface porosity, provides substantial dry and wet adhesion to organic coating systems, making it an eco-friendly priming layer for practical applications requiring post-treatment. • A thin energy-efficient Ce-doped PEO coating is developed (≤ 300 s) on additively manufactured Al10SiMg. • The role of cerium incorporation on PEO structural and corrosion resistance properties is thoroughly investigated. • The overall Ce-PEO coating protection mechanism is proposed. • The Ce-PEO demonstrated strong dry and wet adhesion to the organic system, aided by its intrinsic surface porosity. • The coating offers an eco-friendly alternative for post-treatment applications as a protective primer.