A.D. Modestov

Synergistic Effect of Superhydrophobicity and Oxidized Layers on Corrosion Resistance of Aluminum Alloy Surface Textured by Nanosecond Laser Treatment

We report a new efficient method for fabricating a superhydrophobic oxidized surface of aluminum alloys with enhanced resistance to pitting corrosion in sodium chloride solutions. The developed coatings are considered very prospective materials for the automotive industry, shipbuilding, aviation, construction, and medicine. The method is based on nanosecond laser treatment of the surface followed by chemisorption of a hydrophobic agent to achieve the superhydrophobic state of the alloy surface. We have shown that the surface texturing used to fabricate multimodal roughness of the surface may be simultaneously used for modifying the physicochemical properties of the thick surface layer of the substrate itself. Electrochemical and wetting experiments demonstrated that the superhydrophobic state of the metal surface inhibits corrosion processes in chloride solutions for a few days. However, during long-term contact of a superhydrophobic coating with a solution, the wetted area of the coating is subjected to corrosion processes due to the formation of defects. In contrast, the combination of an oxide layer with good barrier properties and the superhydrophobic state of the coating provides remarkable corrosion resistance. The mechanisms for enhancing corrosion protective properties are discussed.

Influence of Catalyst Layer Binder on Catalyst Utilization and Performance of Fuel Cell with Polybenzimidazole- H3PO4 Membrane

This article reports on the impact of the catalyst layer (CL) binder on the performance of fuel cell (FC) with H 3 PO 4 -doped polybenzimidazole membrane. Nafion and fluorinated ethylenepropylene (FEP) were used as binders for carbon-supported platinum catalyst. FC performance declined with the increase of binder concentration in CL. Nafion binder was found to be more detrimental to FC performance than FEP. Changes of platinum electrochemically active surface area (ESA) in the cathode were evaluated by monitoring ESA of carbon support. ESA of carbon in the CL was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. Carbon support ESA was found unaffected by the increase of binder (Nafion or FEP) to carbon support (C) mass ratio up to Nafion/C = 1 or FEP/C = 0.8. The difference in the influence of these binders on FC performance was ascribed to the difference in arrangement of particles of these binders within the CL.

Application of laser micro- and nanotexturing for the fabrication of superhydrophobic corrosion-resistant coatings on aluminum

A new efficient method for the fabrication of corrosion-resistant composite superhydrophobic coatings on aluminum and its alloys is presented. The laser micro- and nanotexturing of the surface combined with the deposition of a hydrophobic agent makes it possible to obtain superhydrophobic coatings with unique properties on aluminum materials. The complex studies by electrochemical methods and wettability analysis showed that the proposed type of coatings is characterized by very high resistance to corrosion, including pitting resistance, and by the durability of the superhydrophobic state upon prolonged contact with aqueous chloride-containing media.

Electrochemical hydrogen separation from mixtures with carbon monoxide using the membrane electrode assembly of a medium-temperature fuel cell

205 Hydrogen is an ideal fuel for electric power produc� tion by means of fuel cells. Inasmuch as the hydrogen production and delivery infrastructure is currently absent, methods of decentralized hydrogen produc� tion for feeding fuel cells are actively developed. Water