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The use of coatings based on alkoxysilanes is one of the most effective ways to control the release of cytotoxic ions by metal implants. To improve the success rate of titanium–aluminum–vanadium implants, in this study, we evaluated the physicochemical, morphological, mechanical, and electrochemical behavior of hybrid coatings based on alkoxysilanes applied on the alloy. The coatings were prepared with the precursors 3‐(trimethoxysilyl propyl)methacrylate and tetraethoxysilane alkoxides by the sol–gel method. The curing of the coatings was evaluated at different temperatures (90, 180, and 300 °C) for 1 h. We carried out the pretreatment of the alloy by polishing and attacking it with sodium hydroxide. The results indicate that the temperature of 90 °C was effective for solvent evaporation and complete crosslinking of the film, and the alkaline pretreatment allowed the formation of a film with better anticorrosive performance; this indicated that the presence of hydroxyl groups on the surface improved the coating adhesion. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45470.

Powder coatings have been used for coating metal substrates in industrial applications. The incorporation of nanofillers as muscovite mica and montmorillonite (MMT) can improve the properties of the coatings. The objective of this study is to develop, apply and characterize a hybrid powder coating (30% epoxy/70% polyester) adding nanofillers in concentrations of 2, 4 and 6 phr separately in a twin screw extruder. The characterization of the coatings was performed by thermal, mechanical and chemical analysis. The incorporation of clay into the polymer increased the surface roughness resulting in a diffuse reflection of incident light and on a gloss reduction. The muscovite mica presented a lamellar structure, constituted by a set of overlapping parallel plates. The morphology analysis showed that the MMT presented irregular agglomerates resulting in inferior mechanical properties to coatings with muscovite mica. In the salt spray test, all samples showed high corrosion protection, around 850 hours.

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Titanium has been widely used as biomaterial, especially in implantables, in which osseointegration and corrosion resistance are needed. Studies have shown that the thickness and roughness of porous titanium oxides are related to the osseointegration. According to the literature, the best anodizing conditions for obtaining nanotubes in titanium oxide are the use of a voltage of 10V in an electrolyte containing 0.15% HF in H3PO4 (w/v). In this study, was to evaluate the corrosion capacity of simulated body fluid (SBF) over titanium samples anodized on 1 mol. L-1 H3PO4 and 0.15% HF (w/v) in 1 mol.L-1 H3PO4. To perform these evaluations samples of commercially pure titanium grade 2 were used. Samples were analyzed by scanning electron microscopy, atomic force microscopy and by electrochemical corrosion tests in healthy and simulating inflammatory conditions. The hydrophobicity of oxides was tested by sessile drop essay, also using SBF. Results show that oxides obtained in H3PO4 electrolyte, barrier type oxides, work better than the porous oxides obtained in H3PO4/HF electrolyte, suggesting that barrier oxide exhibit more biomaterial characteristics than the porous oxide. These results agree with previous studies, and stand out mainly in relation to the tests performed under inflammatory conditions, more aggressive to the biomaterial.

The fluoride use for anodizing electrolytes has been primarily responsible for the formation of nanoporous oxides at valve metals, except aluminum, since it causes a dissolution process. This study presents the formation of an oxide model according to the following anodizing parameters: 100 V, 12.73 mA/cm², room temperature and the niobium samples anodized in niobium oxalate and oxalic acid electrolytes without and with the addition of HF for 5, 30 and 60 min. The anodized samples were analyzed morphologically by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM) and the hydrophobicity of the samples was assessed by the sessile drop method. The presence of fluor in the niobium oxalate electrolyte formed oxides with lower a dissolution and a low hydrophobicity compared to the one formed in oxalic acid was attributed to the incorporation of niobium and oxalate ions. Thereby, the model proposed in this paper showed that during anodization the migration of the fluoride ion into the oxide occurs at high speed, which results in the formation of microcones, leading to the formation of discrete layers of porous oxide.

Tinplate is used to food packaging and other types of packages. The corrosion resistance of the tinplate has been study due the necessity of an alternative to high environmental impact of chromatization process. Therefore protective coatings as hybrid films base elaborations with different acids are studied to improve the barrier effect against corrosion. The objective of this work is characterize hybrid films deposited on a tinplate from a sol made up of the alkoxide precursors 3-(trimethoxysilylpropyl) methacrylate (TMSM), tetraethoxysilane (TEOS) and poly(methyl methacrylate) (PMMA) together with one of three acids (acetic, hydrochloric or nitric acid) and to verify their action against the corrosion of the substrate. The films were obtained by a dip-coating process and cured for 3 hours at 160 °C. The film hydrophobicity was determined by contact angle measurements, and the morphology was evaluated by SEM. FTIR measurements were performed to characterize the chemical structures of the films. The electrochemical behavior of the coatings was evaluated by techniques open circuit potential monitoring (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results demonstrate that the siloxane-PMMA films improve the protective properties of the tinplate, with the films obtained by acetic acid addition exhibiting the greatest improvement.