Influence of Magnetic Field on Vacuum Arc Discharge Volt-Ampere Characteristics

• Main Authors: D. V. Duhopel'nikov, D. V. Kirillov
• Format: Article
• Language: Russian
• Published: MGTU im. N.È. Baumana 2015-01-01
• Series: Nauka i Obrazovanie
• Subjects: cathodic arc; vacuum arc; voltage; volt-ampere characteristic; magnetic field; plasma
• Online Access: http://technomag.edu.ru/jour/article/view/109

<p>The vacuum arc evaporation technology was developed in the 70-s in the USSR and widely used nowadays for deposition of various functional coatings. Magnetic field provides stabilization of the discharge and cathode spot movement in arc evaporators. Usually, are used two types of magnetic systems: with divergent axisymmetrical magnetic field and with an arch-like magnetic field. The systems with the arch-like magnetic field allow a flexible control of the trajectory and the speed of the moving cathode spot and, recently, have been increasingly frequently used in facilities of vacuum arc deposition of coatings.</p><p>Since the plasma of vacuum arc discharge is almost in completely ionized state even the weak magnetic fields have a significant influence on the vacuum arc discharge volt-ampere characteristics (VAC). Unfortunately, with a wealth of materials concerning the vacuum arc discharge there is still insufficient information about the influence of magnetic field magnitude and shape on the arc discharge VAC of the industrial arc evaporators.</p><p>This work studies the effect of magnetic fields on VAC of two different arc evaporators with a titanium cathode, which possess axial and arch-like magnetic field.</p><p>It was shown that the magnetic field significantly affects the VAC behavior changing it from increasing to descending one. The transition of VAC curves behavior from growing to descending one occurs at magnetic field values of 4.4 mT and 6.5 mT for axial and arch-like magnetic field, respectively.</p><p>Voltage at fixed discharge current linearly increases with raising magnetic field induction. The discharge voltage growth with the arch-like magnetic field is greater than with its axial configuration.</p><p>At the same time in the work the analytical expressions are given. These equations show that the VAC shape modification of the vacuum arc discharge in an external magnetic field may be explained by the inverse proportionality of the Hall parameter on its concentration in completely ionized plasma. A general view of VAC dependence on the magnetic field magnitude is obtained.</p>