Ni/cerium Molybdenum Oxide Hydrate Microflakes Composite Coatings Electrodeposited from Choline Chloride: Ethylene Glycol Deep Eutectic Solvent

Abstract

Cerium molybdenum oxide hydrate microflakes are codeposited with nickel from a deep eutectic solvent-based bath. During seven days of exposure in 0.05 M NaCl solution, the corrosion resistance of composite coating (Ni/CeMoOxide) is slightly reduced, due to the existence of some microcracks caused by large microflakes. Multielemental analysis of the solution, in which coatings are exposed and the qualitative changes in the surface chemistry (XPS) show selective etching molybdenum from microflakes. The amount of various molybdenum species within the surface of coating nearly completely disappear, due to the corrosion process. Significant amounts of Ce3+ compounds are removed, however the corrosion process is less selective towards the cerium, and the overall cerium chemistry remains unchanged. Initially, blank Ni coatings are covered by NiO and Ni(OH)2 in an atomic ratio of 1:2. After exposure, the amount of Ni(OH)2 increases in relation to NiO (ratio 1:3). For the composite coating, the atomic ratios of both forms of nickel vary from 1:0.8 to 1:1.3. Despite achieving lower corrosion resistance of the composite coating, the applied concept of using micro-flakes, whose skeleton is a system of Ce(III) species and active form are molybdate ions, may be interesting for applications in materials with potential self-healing properties.

Electrodeposition of polyfunctional Ni coatings from deep eutectic solvent based on choline chloride and lactic acid

“…The following organic compounds can be acceptors (HBA): organic acids, polyhydric alcohols, urea and its derivatives. A significant amount of printed works has been devoted to the electrodeposition of metal coatings from electrolytes based on DES, such as ethaline (a mixture of choline chloride and ethylene glycol) [7,9,[13][14][15] and reline (a mixture of choline chloride and urea) [16][17][18]. It is well known that galvanic nickel coatings, in terms of their physical, mechanical, and electrochemical properties, are multifunctional and are used both in the fields of special surface treatment of parts and of electrochemical energy conversion.…”

“…Ethaline and reline are most often used as the basis of the electrolyte in the electrodeposition of nickel coatings, as evidenced by the data of most known works [7,9,[13][14][15][16][17][18]. In particular, the disadvantages of the corresponding DES include the following.…”

Special Issue: Recent Advances in Corrosion Science

“…et al [11] and Ryl et al [12] reveal various aspects concerning the search for efficient organic corrosion inhibitors and the tools used to evaluate protection mechanisms. The studies of Parchoviansky et al [13] and Winiarski et al [14] provide an insight on the development of anti-corrosion composite coatings, while an interesting report from Kania and Sipa [15] shows the improved corrosion resistance of anodic zinc coatings, obtained using a new thermal diffusion process.…”

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“…Ключевые слова: электроосаждение, никель, диоксид титана, композиционное покрытие, низкотемпературный эвтектический растворитель, электрокатализ, реакция выделения водорода УДК 621.357 https://doi.org/10.52577/eom.2021.57. 6.01 ВВЕДЕНИЕ Электролитическое осаждение композитов является эффективным способом получения покрытий с комплексом улучшенных физикохимических и эксплуатационных свойств [1,2]. Среди разнообразнейших типов композитов, nкоторые удается получить методом электроосаждения, покрытия на основе никеля представляют особый интерес.…”

“…Альтернативой водным электролитам для осаждения никельсодержащих композиционных покрытий могут стать системы на основе так называемых низкотемпературных эвтектических растворителей (НЭР) (англ. -deep eutectic solvents, DES) [5][6][7][8][21][22][23]. НЭРэто особый класс ионных жидкостей, представляющих собой эвтектические смеси разнообразных неорганических и органических компонентов, в которых за счет взаимодействия между частицами (формирование водородных связей и (или) донорно-акцепторные взаимодействия) протекает электролитическая диссоциация компонентов и резко снижается температура плавления (по сравнению с температурами плавления индивидуальных составляющих) [24,25].…”