Comparative evaluation of cerium oxide primers electrodeposited on AA2024‐T3 and D16 AM aircraft alloys

Abstract

As a common practice, the metallic alloys are always protected by multilayer coating systems against environmental corrosive impact. The primer layers of these coating systems serve for improvement of the adhesion between the upper and finishing coating layers and the metallic substrate (cerium oxide primer (CeOP) layers). Furthermore, the structural and morphological features possessed by the coating primers strongly depend on the metallic surface roughness, and composition. In the present research work, cerium conversion coatings were electrodeposited on two different aircraft alloys, with identical chemical compositions (AA2024-T3, and D16 AM). The relation between the protective capabilities of the obtained layers and the structural features of the respective alloys was elucidated by electrochemical measurements, via linear voltammetry (LVA) and electrochemical impedance spectroscopy (EIS), combined with SEM/EDX observations.

Enhancement of the cerium oxide primer layers deposited on AA2024-T3 aircraft alloy by preliminary Enhancement of the cerium oxide primer layers deposited on AA2024-T3 aircraft alloy by preliminary anodization

“…The EDX images clearly reveal Mg re-deposition and sulfur entrapment in the AAO/ CeOPL layer composition. Unlike the results from previous works [8] the CeOPL layers deposited on the already anodized AA2024-T3 samples cover completely the metallic surface possessing dense structure and uniform element distribution (Fig. 10).…”

“…Consequently, CeOPL deposition mechanism alteration occurs on the more completely hydrated AAO layers, occupying the entire metallic surface. Thus, the CeOPL deposition follows the mechanism, proposed by Conde et al [29], described by reactions (7) and (8).…”

“…Although the anodization process is well investigated for pure aluminum [1], its highly doped alloys reveal significant deviations from the expected behavior, due to their compositional and structural heterogeneity [2][3][4][5][6][7][8][9]. In the latter case, the intermetallic inclusions entirely predetermine the mechanism and kinetics of both the primer protective layer deposition and the corrosion processes.…”

Advanced Multifunctional Corrosion Protective Coating Systems for Light-Weight Aircraft Alloys—Actual Trends and Challenges

“…Thus, although the same chemical composition, the obtained alloys could possess completely different mechanical properties, predetermined by the finishing metallurgical thermal treatment. Indeed, in another comparative investigation, involving CeOPL deposition at the same regime on AA2024-T3, and its Russian analogue-D16 AM tempered clad alloy [101], it was established that the CeOPL is much more uniform and fine grained in the former case, whereas in the latter case, the film is less uniform, because of the tempered shielding layers (Figure 12).…”

Elucidation of the Anodization and Silver Incorporation Impact on the Surface Properties of AA1050 Aluminum Alloy

“…This is possible, because the Al-substrate metallic matrix is rather a solid solution. 93,94 Thus, during the anodization, the included alloying metals coincide the Al 3+ transportation through the growing oxide layer. 27 This assumption is confirmed by the occurrence of white spots inside the Al-O-Ag layer notable in the cross-sectional SEM (Fig.…”