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Influence of sodium hydroxide on the rate and nature of corrosion of St3 carbon steel and SCh 18-36 grey cast iron in highly mineralized recycling water was studied. The nature of the corrosion damage was determined and the weight index of corrosion of these alloys was calculated. By means of polarization measurements, the electrochemical indices of anodic processes on steel and cast iron were determined. The effect of the circulating water pH on behavior of steel and cast iron under anodic polarization has been studied by cyclic voltammetry. It has been shown that the effective impact of pH on characteristics of the anode processes occured at pH≥11.4. At these pH values, the metal steady-state potential shifted to a region of positive values which was an indication of inhibition of the anodic process itself. At pH≥11.4, the pitting potential significantly shifted to the positive side: the process of healing pits was faster than their formation. It has been established that steel and especially cast iron tend to pass into a passive state at pH> 10. The corrosion rate values did not exceed this index for the studied alloys in distilled water and were in the range of acceptable values. Thus, it is possible to effectively inhibit the rate of steel and cast iron corrosion, especially in the waterline zone by shifting the pH of the circulating water to the alkaline region. As a result of the conducted studies, optimal working conditions for iron alloys as the most technically important structural materials for designing closed cycles of circulating water supply systems have been established.

This paper reports results of studying the features of the formation of thin interference-colored oxide films on the alloy Ti6Al4V alloy in solutions of carboxylic acids. It has been established that a change in voltage on the cell corresponding to the molding dependence of the alloy depends on the anodic current density. At current densities

The influence of lithium hydroxide was examined on the characteristic features of charge and discharge and electrical parameters of the sintered oxide-nickel electrode in a solution of potassium hydroxide. It is shown that the introduction of LiON to the composition of electrolyte does not lead to a change in the specificity of charge and discharge processes of the electrode. The experimental work conducted allowed us to establish dependences that connect the magnitude of analytical concentration of the Li⁺ ions to specific capacity and capacity output of the electrode. The results obtained show that an increase in the content of Li⁺ ions in the electrolyte from 1 to 100 g·l⁻¹ causes a growth of the electrode’s specific capacity from 0.79 (А·h)·cm⁻² to 1.84 (А·h)·cm⁻². It is optimal to introduce LiOH to the electrolyte in the amount of 30‒50 g·l⁻¹. It was established that the magnitude of specific capacity of the oxide-nickel electrode depends on the number of charge-discharge cycles and increases with an increase in the number, which is related to the slow character of the course of mass transfer processes in the volume of active mass of the electrode. Описаны результаты исследования по определению влияния добавки гидроксида лития на удельную ёмкость, отдачу по емкости и особенности заряда и разряда оксидно-никелевого электрода. Показано, что введение ионов Li⁺ в состав электролита не вызывает изменения особенностей процессов заряда и разряда электрода и обуславливает повышение его удельной электрической емкости. На основании полученных экспериментальных данных установлена взаимосвязь между концентрацией добавки в растворе и ее влиянием на исследованные эксплуатационные характеристики системы.

The impact of the chloride ions concentration and the temperature of the circulating water on the process of corrosion destruction of carbon steel and cast iron has been investigated. It has been shown that an increase in the concentration of chloride ions causes a shift in the values of the stationary potentials of steel and cast iron to the region of negative values and reduces the passive state of these alloys. This leads to an increase in the corrosion rate of St.3 steel and CI 18-36 cast iron. The results of electrochemical studies have shown that the more reliable protective films are formed on steel than on cast iron. The limiting concentration of NaCl, at which reliable operation of equipment made from these alloys is possible, depends on the pH of the solution. At pH=7, it is about 1.2 g l⁻¹, which is about an order of magnitude less than at pH=12. When the circulating water temperature rises, the corrosion rate of steel and cast iron increases. The stationary potentials of steel and cast iron are shifted to the negative range, and the polarization of the anode process decreases. Corrosion process is limited by the rate of oxygen supply to the cathode areas. Досліджений вплив концентрації іонів хлору і температури оборотної води на процес корозійного руйнування вуглецевої сталі і сірого чавуну. Встановлено, що збільшення концентрації хлорид-іонів обумовлює зміщення величин стаціонарних потенціалів сталі і чавуну в область негативних значень і зменшує область пасивного стану зазначених сплавів. В результаті проведених досліджень встановлено, що обладнання, виготовлене з сталі Ст. 3 і чавуну СЧ 18-36, можна використовувати в оборотній воді з рН=12, що містить до 10 г∙л⁻¹∙NaCl при температурі не більше 40 °C.