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Surface Treatments of Load Bearing Bio-implant Materials
Published in Savaş Kaya, Sasikumar Yesudass, Srinivasan Arthanari, Sivakumar Bose, Goncagül Serdaroğlu, Materials Development and Processing for Biomedical Applications, 2022
K. Saranya, P. Agilan, M. Kalaiyarasan, N. Rajendran
The process of converting the native surface oxides to new oxides/compounds with the aid of chemicals to achieve the desirable properties is called conversion coating. The modified layer is anticipated to provide better corrosion resistance and satisfy the requisites of biocompatibility (Saranya et al. 2019). Conversion coating is a strong adhesive coating that is formed by wetting the metal in an electrolyte with external power (electrochemical conversion or anodization) or without external power (chemical conversion). The superficial layer of the substrate interacts with the chemical bath solution forming a consistent coating layer and an intermittent chemical bonding layer (Chen et al. 2015).
Adhesion and Barrier Properties of Protective Coatings
Published in Ole Øystein Knudsen, Amy Forsgren, Corrosion Control Through Organic Coatings, 2017
Ole Øystein Knudsen, Amy Forsgren
Modifying the surface chemistry of the substrate is another way of improving adhesion. On metals, this is typically achieved by applying conversion coatings. The conversion coating improves adhesion by either introducing microscopic roughness on the surface, introducing new chemistry on the surface, removing impurities, or stabilizing the surface chemically, or a combination of these. Frequently used conversion coatings include phosphating, chromating, anodizing, titanium– zirconium-based, and chromium III– based conversion coatings. The various types of conversion coatings are discussed in Chapter 9.
EUROCORR 2017 in combination with the 20th International Corrosion Congress and the Process Safety Congress 2017: corrosion control for safer living, part 4
Published in Corrosion Engineering, Science and Technology, 2018
The same presenter also described the ‘Effect of fluoride treatment of Mg alloy on the corrosion properties’ of an Mg–Ca–Zn alloy produced by powder metallurgy for scaffold applications in tissue engineering. The fluoride conversion coating was synthesised in situ on the alloy by immersion in hydrofluoric acid. The surface was then treated by immersion in sodium hydroxide followed by drying and then immersion in hydrofluoric acid. The Young’s modulus increased with increasing zinc content. The corrosion resistance increased in the presence of the conversion coating. The electrochemical polarisation resistance increased from ∼120 Ω cm2 at 1 wt-% Zn to ∼133 Ω cm2 at 3 wt-% Zn, subsequently decreasing with further additions of zinc to ∼115 Ω cm2 at 8 wt-% Zn.
8-Hydroxyquinoline/nanoclay epoxy nanocomposite as a smart coating for early corrosion detection
Published in Corrosion Engineering, Science and Technology, 2021
H. Eivaz Mohammadloo, A. A. Sarabi, Sh. Roshan, A. Eivaz Mohammadloo
Third: Ti/Ni conversion coating enhances the adhesion of the organic coating to the metal substrate by forming Vander-Walls and hydrogen bonds with epoxy coating. However, it can improve adhesion by mechanical interlocking mechanism because of its rough surface. Asemani et al. [52] investigated the anti-corrosion performance of the epoxy/corrosion inhibitor system, which was applied on the Zr treated steel surface. They reported that conversion coating could significantly reduce coating delamination by improving adhesion property and increasing long-term anti-corrosion performance.