The initial stages of the onset of a corona discharge in a wet porous oxide layer during the passage of a high voltage current

Abstract

The physical and chemical processes occurring in non-metallic inorganic porous coatings during the passage of a high-voltage alternating sinusoidal current through metal conductors on which the coatings under study are applied are investigated by the method of mathematical modeling. Compositions of electrolytes and modes of formation of coatings have been developed, and their characteristics have been determined. The option of a wet coating is considered. It was found that at a high voltage in pores filled with a liquid, fast electrode reaction take place, reducing the number of charge carriers in the liquid and increasing the voltage drop in the oxide layer. The simulation results showed the theoretical possibility of corona discharge suppression by 80%. In practice, when an electric current with a voltage of up to 75 kV passes through wires with a diameter of 5.5 mm, the developed coatings reduce power losses for corona discharge by 20% and increase the voltage of corona discharge on the wires by 3 kV.

Methods for the study and control of microplasma processes in the synthesis of coatings

“…Impulse processes at the initial moment have a high speed. The pause between pulses allows the system to restore equilibrium and return to its initial state without energy consumption [6][7][8][9][10]. The trapezoidal pulse with steep rising and falling fronts of the potential voltage has sections with alternating and constant voltages, which makes it possible to evaluate the ongoing processes and the state of the coating by various methods during a short period of time when the system is unequilibrium, in an excited state, and when equilibrium is restored.…”

“…This type of plasma refers to low-temperature plasma under pressure. This process was used to obtain non-metallic inorganic coatings, which are very much in demand in industry [6][7][8][9][10]. Other teams of scientists are also developing the conditions for microplasma production of coatings, for example, P.S.…”

“…Sturdy methods based on the electrical characteristics of microplasma processes occurring during the current passage in the electrolyte solution are not enough. Therefore, the authors [6][7][8][9][10] propose to use high-voltage (100−400 V) trapezoidal pulses of polarizing voltage as the most effective type of current from the point of view of versatile control of microplasma processes. Depending on the parameters of action, the process of producing the coatings and films can be electrochemical or plasma.…”

“…To study microplasma processes using trapezoidal pulses of polarizing voltage, it is necessary to develop more complex special voltage sources, which was done by the authors of this paper. Previous theoretical and experimental studies [6][7][8][9][10] resulted to the conclusion that the trapezoidal shape of voltage pulses is by ten times more efficient in terms of energy consumption compared to other types of current, which is very important from a technological point of view. The trapezoidal shape of the voltage was also chosen from the considerations of the most constant conditions for the coating formation from the energy impact point of view.…”