Zinc Anodizing: Structural Diversity of Anodic Zinc Oxide Controlled by the Type of Electrolyte

Abstract

Anodic zinc oxide (AZO) layers are attracting interdisciplinary research interest. Chemists, physicists and materials scientists are increasingly devoting attention to fundamental and application‐related research on these layers. Research work focuses on the application as semiconductor, corrosion protector, adhesion promoter, abrasion protector, or antibacterial surfaces. The structure and crystallinity essentially determine the properties of the AZO coatings. The type and concentration of the electrolyte, the applied current density or voltage as well as the duration time enable layer structures of structural variety. The article gives an overview of the different possibilities of anodic treatment, whereby the voltage and the current type are the main distinguishing criteria. Presented is the electrolytic oxidation (anodizing) and the electrolytic plasma oxidation (EPO). The electrolytic etching is also a process of anodic treatment. However, it does not produce AZO layers, but rather a degradation of the zinc layer. The review article shows the parameters used so far (electrolyte, current type, current density, voltage) and points out the influence on the formation of AZO structures in dependency to the used electrolyte.

Innovative Applications of Cerium Oxide-Based Materials in Civil Engineering, Automation, and Energy Sectors

“…The quality of the resulting galvanic layers depends on both the electrolyte composition [190][191][192], the applied galvanizing regime [191], and the posttreatment applied. This procedure can be executed through anodization [192][193][194][195][196], similar to the case of aluminum discussed earlier, or by the deposition of Ce-modified hydrotalcites, as proposed by Pham et al [197,198]. In summary, among the most promising approaches for corrosion protection could be achieved by subsequent performance of: (i) galvanization; (ii) galvanic layer anodization; (iii) CeCC layer deposition; (iv) phosphate sealing; and (v) hydrotalcite finishing, combined with (vi) advanced polymer deposition.…”

Electrochemical assessment of the barrier ability of galvanic Zn coating primers electrodeposited on low-carbon steel

“…In this context, Giurlani et al [9] underscore the escalating interest in galvanic Zn layers, highlighting their diverse applications in corrosion protection, decorative purposes, microelectronics, automotive, urban planning, aircraft, and spacecraft sectors, among others. Furthermore, Zn layers can be subjected to additional anodization, acquiring further advantageous properties [10,11]. Apart from the application of specific electrical regimes [10,12], the electrolytes used for Zn deposition [13-15] play a crucial role in determining the composition, structure, and resulting properties of the Zn layers.…”

“…Furthermore, Zn layers can be subjected to additional anodization, acquiring further advantageous properties [10,11]. Apart from the application of specific electrical regimes [10,12], the electrolytes used for Zn deposition [13-15] play a crucial role in determining the composition, structure, and resulting properties of the Zn layers. Furthermore, these coating primers can undergo modifications, such as anodization [7, 8, 16] or additional sealing [17,18].…”

Influence of the final thermal sealing on the properties of combined anodic alumina/cerium conversion coatings on AA2024-T3 aircraft alloy

“…On the other hand, anodization is an established and efficient method used for the electrochemical formation of oxide layers on aluminum [31 -33], copper [34], zinc [35,36], titanium, [37,38] and other valve metals [39,40]. Indeed, it was recently shown that the combination of formation of cerium conversion coatings with anodization enables the successful formation of combined Al 2 O 3 /CeCC coating primers [41].…”