Fe–Mn Alloys Electroforming Process Using Choline Chloride Based Deep Eutectic Solvents

Aqueous solvents, despite being effective in the electrodeposition of metals with positive reduction potential, fail to deposit metals with negative reduction potential due to their narrow electrochemical potential window. Deep eutectic solvents (DESs), a class of ionic liquids, are a promising alternative of inexpensive, biodegradable, non-toxic anhydrous solvents that present wide electrochemical potential windows. The present work reports on the potential of choline chloride/ethylene glycol DES in the electrodeposition of Fe–Mn alloys. Cyclic voltammetry tests showed that increasing the quantity of Mn in the bath composition decreases the deposition current of the alloy.

Electrodeposition of Copper and Brass Coatings with Olive-Like Structure

One method of creating a brass coating is through electrodeposition, which is most often completed in cyanide galvanic baths. Due to their toxicity, many investigations focused on the development of more environmentally friendly alternatives. The purpose of the study was to explore a new generation of non-aqueous cyanide-free baths based on 1-ethyl-3-methylimidazolium acetate ionic liquids. The study involved the formation of copper, zinc, and brass coatings. The influence of the bath composition, cathodic current density, and temperature was determined. The obtained coatings were characterized in terms of their morphology, chemical composition, phase composition, roughness, and corrosion resistance. It was found that the structure of the obtained coatings is strongly dependent on the process parameters. The three main structure types observed were as follows: fine-grained, porous, and olive-like. To the best knowledge of the authors, it is the first time the olive-like structure was observed in the case of an electrodeposited coating. The Cu-Zn coatings consisted of 19–96 at. % copper and exhibited relatively good corrosion resistance. A significant improvement of corrosion properties was found in the case of copper and brass coatings with the olive-like structure.

Electrodeposition of Copper and Brass Coatings with Olive-like Structure

One method of creating a brass coating is through electrodeposition, which is most often completed in cyanide galvanic baths. Because of the toxicity of cyanides, many are working on the development of cyanide-free baths, which are promising but not satisfactory to replace the classic methods. The purpose of the study was to explore a new generation of non-aqueous cyanide-free baths based on 1-ethyl-3-methylimidazolium acetate ionic liquids. The study involved the formation of copper, zinc, and brass coatings. The influence of the bath composition, cathodic current density, and temperature was determined. The obtained coatings were characterized by their morphology, chemical composition, roughness, and corrosion resistance. It was found that the structure of the obtained coatings is strongly dependent on the process parameters. The three main structures observed were fine-grained, porous, and olive-like. To the best knowledge of the authors, it is the first time the olive-like structure was observed in the case of an electrodeposited coating. The Cu-Zn coatings consisted of 19–96 at.% copper and exhibited relatively strong corrosion resistance. High improvement of corrosion properties was found in the case of copper and brass coatings with an olive-like structure.

Electroless deposition bicomponent dispersed phase composite coatings

The deposition of bicomponent composite coatings containing both hard and soft particles is studied. Technologically important characteristics (deposition rate, coating composition) of electroless deposition of bicomponent Ni—Cu—P— Cr2O3—MoS2 composite coatings from slightly acidic baths are determined. Bath composition, mol/L: NiSO4 — 0,12; CuSO4 — 0,0016; NaH2PO2 — 0,37; NH2CH2COOH — 0,13; Succinic acid — 0,18; Pb (CH3COO)2 — 10–5; рН 6,5. A mixture of dispersed hard particles (Cr2O3) and soft particles (MoS2) was added to the solution for electroless deposition of a copper doped Ni—P alloy. It was found that when adding a mixture of dispersed Cr2O3 (40...25 % wt.) and MoS2 (60...75 % wt.) at a concentration of 10 g/L, the solution remains stable during deposition and allows the formation of Ni — Cu (1...1.5 wt.%) — P (4 wt.%) — Cr2O3(3 % wt.) — MoS2 (0.12— 0.16 % wt.) coatings at a rate of 15 mg/(cm2 •h). Deposited coatings after heat treatment at 400 °C has a microhardness of 11.1...11.2 GPA. It is concluded that the technology of electroless deposition of bicomponent composite coatings Ni—Cu—P—Cr2O3—MoS2 is promising for obtaining materials with increased hardness and wear resistance.