Авіаційно-космічна техніка та технологія (Apr 2020)
CONTROLLING THE COMPOSITION OF THE PLASMA FLOW OF VACUUM-ARC SOURCES
Abstract
The problems of managing the amount of drop fraction in the plasma flow of technological plasma vacuum-arc discharge sources by controlling the changing the cathode surface temperature were considered. Such temperature control of the cathode work surface allows obtaining coatings following the functional requirements for them with both minimal and maximum content of drip fraction. It is determined that the parameters that affect the temperature of the working surface of the cathode, in the general case are: the density of heat flux coming from the discharge on the working surface of the cathode; the thermal resistance of the cathode, which is determined by the distance between the working surface of the cathode and its cooling zone; the temperature of the cooling surface of the cathode. The possibilities for regulation and stabilization of cathode surface temperature by cooling the front and the lateral cathode surface were investigated. In the construction of the plasma source with the cooling of the butt-end cathode surface, the restricted cathode surface temperature control is able by changing the temperature of the cooling cathode butt-end. The application of the temperature control of cooling liquid and at the same time control of its flow through the cooling zone could significantly reduce the operating costs. The plasma source with the cathode cooling by lateral surface allows changing the temperature of the cathode working surface over a wide range by varying the distance between the cathode working surface and the cooling area. The stabilization of the set temperature of the cathode surface is maintained by setting the distance between the cathode working surface and the cooling area (by moving the cathode with a speed equal to the speed of cathode material evaporation. The plasma source with the cathode cooling by lateral surface the changing of the cathode working surface temperature is able during the deposition process by changing the distance between the cathode working surface and the cooling area (according to a predetermined program).
Keywords
