Кафедри
Постійне посилання на розділhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/35393
Переглянути
6 результатів
Результати пошуку
Документ The effect of butil alcohol on anodic brass oxidation processes in phosphate electrolytes(Kamianets-Podіlskyi National Ivan Ohiienko University, 2020) Silchenko, Dar'ja; Shkolnikova, T.; Pancheva, Hanna; Pilipenko, AlexeiДокумент Chemical deposition of CdS films from ammoniac-thiourea solutions(Технологический центр, 2018) Pancheva, Hanna; Khrystych, Olena; Mykhailova, Evgeniia; Ivashchenko, Maryna; Pilipenko, AlexeiThis paper investigates the process of chemical deposition of CdS films from ammonia-thiourea solutions. It was established that a change in the turbidity of solution occurs in the process of chemical deposition. The results of visual observations and measurement of turbidity of solution allowed us to establish that these dependences could be used to monitor the status of the process. Visual observations correlate with the obtained dependences for turbidity and suggest that the chemical deposition of CdS includes the accumulation of colloidal-dispersed precipitate in the volume of solution, agglomeration of CdS particles, and a stationary mode of the CdS film growth at the surface of a sample. The first stage of the process is matched by a sharp increase in the turbidity of solution; the second stage is accompanied by the emergence of a maximum in the dependence. No significant change in turbidity occurs at the third stage. The observation of morphology of the resulting precipitate allowed us to establish working concentrations of reagents in solution, which ensure obtaining a high-quality CdS film with a thickness not less than 100 μm. The working concentrations of cadmium chloride, ammonia, and thiourea are, respectively, 1.8, 0.6, and 8.4 g·l⁻¹. It was assumed that the CdS formation is accompanied by the formation of thiourea. This is confirmed by data on the analysis of a working solution. An analysis of the solution revealed high concentrations of the CO₃²⁻ ions, which are a product of the thiourea decomposition. The data obtained are a preliminary stage in the development of a technology of chemical deposition of CdS films from ammonia-thiourea solutions.Документ Study of anode processes during development of the new complex thiocarbamide-citrate copper plating electrolyte(Технологический центр, 2018) Smirnova, Olha; Pilipenko, Alexei; Pancheva, Hanna; Zhelavskyi, Alexei; Rutkovska, KaterynaThe kinetics of anodic reactions occurring on copper in thiocarbamide-citrate solutions was studied. Thiocarbamide forms stable copper (I) complexes of the cationic type with a coordination number equal to unity. Citric acid ensures acid pH value of electrolyte and causes active dissolution of copper under conditions of anode polarization. The joint presence of CS(NH₂)₂ and C₆H₈O₇ in the solution contributes to the copper electrode activation under conditions of anodic polarization. Increasing the concentration of thiocarbamide leads to a drastic shift of copper dissolution potentials towards the region of negative values. Study of the kinetics of anodic behavior of copper by acquiring the voltammograms revealed the nature of the limiting stage of reaction. It is shown that the process of dissolution in a thiocarbamide-citrate electrolyte is controlled by the diffusion phase. This is confirmed by the results of graphical processing of polarization dependences in coordinates η–lg(1–ja/jd). An increase in υр within 5‒100 mV·s⁻¹ causes an increase in jd from 2.2 to 12.0 mА·cm⁻², which indicates diffusion control over the process. The process of copper dissolution proceeds under stationary mode with uniform etching of intragrain boundaries and volume of the metal's grain.Документ Study into the influence of concentration of ions of chlorine and temperature of circulating water on the corrosion stability of carbon steel and cast iron(Технологический центр, 2017) Pancheva, Hanna; Reznichenko, Ganna; Miroshnichenko, Nataliya; Sincheskul, Alexander; Pilipenko, Alexei; Loboichenko, ValentynaThe 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.Документ Design of the modified oxide-nickel electrode with improved electrical characteristics(Технологический центр, 2017) Sincheskul, Alexander; Pancheva, Hanna; Loboichenko, Valentyna; Avina, Svetlana; Khrystych, Olena; Pilipenko, AlexeiThe 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.Документ Establishing the patterns in anode behavior of copper in phosphoric acid solutions when adding alcohols(Технологічний центр, 2018) Silchenko, Dar'ja; Pilipenko, Alexei; Pancheva, Hanna; Khrystych, Olena; Chyrkina, Marina; Semenov, EvgenyWe have investigated the anodic polarization dependences of the copper electrode in phosphate-alcoholic solutions. The dependences derived can be divided into regions, each of which corresponds to the course of certain electrochemical reactions within the specified range of potentials.