Электрохимический синтез композиционных покрытий Ni/TiO2 из низкотемпературного эвтектического растворителя и электрокаталитические свойства осадков

Kinetics of electrodeposition of composite Ni/TiO2 coatings was studied using the electrolyte based on a deep eutectic solvent (DES) containing choline chloride, ethylene glycol, water additive, and nickel chloride. Degussa P 25 nanopowder was used as a dispersed phase in the electrolyte (1–10 g dm3). The developed electrolyte allows depositing composite coatings with the content of titanium dioxide reaching ~ 10 wt.%. The electrolytic deposition of the composite was shown to obey Guglielmi's kinetic model. The main parameters of co-deposition of TiO2 particles into a nickel matrix were determined in the framework of this kinetic model. The co-deposition of titanium dioxide was found to inhibit the reaction of the nickel ions discharge. Electrocatalytic properties of the prepared composite Ni/TiO2 coatings were evaluated with respect to the hydrogen evolution reaction in an aqueous alkaline solution. A noticeable improvement in the electrocatalytic activity was observed when titanium dioxide particles were introduced into an electrodeposited nickel matrix.

Studies and Research on the Influence of Deposit Parameters on the Characteristics of Composite Coatings Ni-Al2O3 Obtained by Electrochemical Methods

The paper presents the characterization of composite coatings with nickel matrix using as dispersed phases Al2O3 particles, both from the microstructural point of view and from the point of view of the layer thickness, micro-hardness and corrosion behavior in saline fog. The presence of dispersed phase particles led to the finishing of the structure because they acted as nucleus centres, reducing the size of nickel crystallites. The parameters of the deposits influence the structure and properties of the obtained layers.

Durability of working bodies of soil-cultivating machines strengthened by composite electrolytic coatings (CEC)

The task of this work is to find the optimal ratio between the size of the particles of silicon carbide and their volumetric content in the nickel matrix to provide maximum characteristics of strength and wear resistance of the working bodies of soil-processing machines. The article investigates the processes of forming complex electrolytic coatings (CEC) on a nickel basis with particles of the filler of various sizes of silicon carbide (SIC). It has been established that the formation of a sicle size sicle and SiC5 is carried out on a vertical, and all other particles in a horizontal cathode. The volumetric content of SICnano and SiC5 particles in nickel reaches a maximum of about 10%, and SiC100 – 46 %. Cap with particle size 28/20 and 50/40 μm allow you to get the most wear-resistant coatings. In this case, the coating with particles 28/20 μm have higher wear resistance, but coating with particles 50/40 μm are more technological when they are formed. The size of the filler particles has a significant effect on the tribological characteristics of the CEP, namely wear resistance and friction coefficient. It has been established that the highest wear resistance and the smallest friction coefficients are characterized by coatings having as a filler of fractions 28/20 and 50/40 μm. Tribological studies show the promise and efficiency of the CEP to increase the wear resistance of the working bodies of soil-cultivating machines.

Change in matrix saturation with alloying elements at primary thermocyclic processing of 44NKhTYu alloy

The total solubility of alloying elements (chromium, titanium, aluminum) in the iron-nickel matrix (Fe – Ni) of 44NKhTYu alloy, depending on the number of cycles, does not occur during primary thermocycling processing (TCP). This is evidenced by the main replicas of the matrix with (111) reflection plane indexes of the samples X-ray images under the studied modes of thermocyclic processing. The maximum solubility of alloying elements is achieved only at total quenching. Special attention should be paid to the third and fourth cycles in the further study of TCP changing the cooling rate in these cycles due to the cooling medium, since with an increase in the number of cycles in the primary TCP, significant changes do not occur.