Advantages of Vacuum electric arc coating methods:
Beams of atoms and ions are a unique tool for nanotechnology to develop new coatings and materials, including those that can not be obtained by other methods. By “placing” certain atoms in a given place of solid body lattice, we “build” unique materials and coatings with unique properties.
Why plasma beams, rather than ionic?
Coating and material technologies of monatomic, mono-energetic ion beams, having a unique opportunity to create materials with different structures and properties, also have essential restriction on the rate of formation of coatings and materials. Charged ions in the beam are repelled from each other, which leads to expansion of the beam and reduces the flux of ions – number of ions per unit of beam area cross-section. It results in decrease in the number of ions per unit of substrate area, and decrease in the rate of formation of coatings and materials.
Ion beams are widely used in microelectronics to create ultrathin structures and coatings, which are essentially two-dimensional and mechanically static. To create 3-D structures, coatings, and material with a thickness of microns, tens or hundreds of microns, ion beams are virtually unusable. Time of formation of such structures may be tens or hundreds of hours and more. It is unacceptable for wide practical application, and in most cases it is virtually impossible to implement.
Plasma is a “mixture” of ions and electrons. Positive ion charge is compensated by negative charge of electrons. In quasi-neutral plasma there is no “repulsion” of particles and reduce of the flux of ions due to this fact. Use of plasma flows provides a high rate of formation of coatings and materials.
Why electric-arc method?
Electric-arc method provides highly ionized plasma beam for a wide range of materials. Electric-arc plasma beam is highly ionized, that means it is composed primarily of ionized (not neutral) atomic particles. For some materials the degree of plasma ionization reaches 100%. High degree of ionization makes it possible to control plasma beam characteristics with electric and magnetic fields – to accelerate and brake ions in plasma beam, focus and defocus the beam, convey, rotate and separate plasma, etc. This allows to purposefully shape the structure and properties of coatings and materials.
Other PVD-methods (physical vapour deposition)such as sputtering, including magnetron sputtering, evaporation of materials with electronic or laser beam, etc. as a rule, form a vapor flow of atomic particles or a flow with a low degree of ionization. It is almost impossible to control the flow of neutral particles – the particles are deposited on the substrate with virtually the same characteristics, whith which they “evaporated” from the target. The process of forming the structure and properties of coatings and materials is hard to control.
The development of plasma electric arc technology was constrained with contamination of beam plasma with microparticles (drops). Our developed CALT SID method (Cathodic Arc Low Temperature Separated Ion Deposition) – application of coating from separated plasma of arc discharge at low temperature is a new trend in electric arc technology. The method is based on obtaining materials from a wide-beam high current highly ionized gas-metallic plasma beam purified from micro- and neutral particles. The method solves many problems that exist in the coating of plasma arc discharge.