Novel anodic oxide film with self-sealing layer showing excellent corrosion resistance

Abstract

In the present work, the novel anodic oxide film (AOF) with self-sealing layer was successfully fabricated on 2024Al alloys by using an improved anodic oxidation method. The presence of the self-sealing layer on the porous layer of AOF was verified by Field emission scanning electron micro scope. Confocal laser scanning microscope (CLSM) and X-ray photoelectron spectroscopy (XPS) were used to evaluate the morphology and the corrosion products of the AOF after salt spray test. The microhardness test showed that the self-sealing AOFs still displayed high hardness even after salt spray test. Electrochemical test and salt spray test results illustrated the excellent corrosion performance of the novel structured self-sealing anodic oxide film (SAOF) compared with common porous AOFs. The narrow diameter makes it difficult for chlorine ions ingress into the pores of SAOFs. The self-sealing layer played an important role in protecting the SAOF from corrosion.

Insights into energy-efficient and eco-friendly sealing of anodic aluminum oxide film holes with alkaline earth metal salts

“…The smaller the weight loss value, the higher the sealing quality. The samples 4, 5,6,9,11 and 16 also possess the satisfactory staining level of 0 or 1 ( Fig. 2a), thus indicating that weight loss test results are in great consistence with that of the antistaining adsorption test.…”

“…According to the ISO3210:19835 standard, the samples with the weight loss of below 30 mg dm À2 are qualied. It can be noted that the samples 4, 5,6,9,11, and 16 exhibit a weight loss smaller than 30 mg dm À2 , revealing a qualied sealing. The remaining samples have an excessive weight loss, implying a poor anticorrosion performance and a low sealing quality.…”

“…4 As a consequence, it is highly desirable to appropriately seal the micropores of the oxidation lm. 5 Many hole sealing methods have thus been explored, primarily including boiling water (steam), nickel salts, and polymer resins-based sealing. 6 However, some obvious defects of these sealing methods seriously limit their widespread applications, such as (i) high energy consumption and low sealing quality as for the steambased sealing, (ii) strong toxicity of nickel salts which pose serious threats to the environment and humans regarding the nickel slat-based sealing, and (iii) a strong barrier for diffusion of the larger polymer molecules into the interior of the oxidation lm, in addition to the unwanted change of the surface properties of the oxidation lm aer the polymer resin-based sealing, thus debasing the sealing effect.…”

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

“…This article focuses on the anodizing process in different electrolytes and shows the relationship between the AZO formation in various electrolytes depending on other anodizing parameters. Anodizing of zinc products leads to further possibilities for application such as wear protection for tools, [36] sensor technology, [37] automotive and aircraft construction, [38][39][40] biomedical and medical technology. [41][42][43]…”

A Solution-Processable, Nanostructured, and Conductive Graphene/Polyaniline Hybrid Coating for Metal-Corrosion Protection and Monitoring

“…It is also important to note that the corrosion of electrical/electronic components is insidious and cannot be easily detected in sophisticated devices. A rich variety of anti-corrosive coatings consisting of small molecules, polymers, carbon species, oxides, and alloys are available 5 – 15 . Anticorrosive mechanisms involve barrier, inhibitive, and galvanic effects, depending on the nature of the anti-corrosive coating material 5 , 6 .…”