Features of the process of vacuum-arc produced Ti-plasma flux deposition under gas pressure of 1 to 10Â Pa

The present study has been carried out to show a particular influence of the pressure of different gases and substrate size on the vacuum-arc coating deposition rate. The coatings were deposited using the plasma source with plasma flow focusing. The measurements were made on the sample surface faced to the plasma source and on the back surface. The effect of the substrate diameter on the deposition rate has been investigated. The diameter of the substrate was changing within the range from 30 to 110 mm. P. 1. The effect of the focusing coil magnetic field on the deposition rate is under consideration. The magnetic field was varying within the range from 0 to 8 mT. The investigation results reveal the following peculiarities of the vacuum-arc coating deposition process in the gas pressure ranging from 1 to 10 Pa. The dependences of deposition rates on the pressure are different for different gases. In nitrogen under pressure from 1.5 to 5 Pa the coating deposition rate increases, and in argon and oxygen under the same pressure it decreases. In nitrogen the coating deposition rate increases on both the front and back substrate surfaces. The deposition rate increases according to the size of substrates. On the substrates having less than 50 mm in diameter the deposition rate increases significantly. In the range of nitrogen pressures from 2 to 10 Pa the deposition rate is in the strong dependence on the magnetic field induction. This effect can be related with the change in the spatial distribution of condensed particles due to the electric field structure change leading to the particle accumulation in the coating deposition region. Under pressure below 1 Pa the deposition rate weakly depends on the magnetic field. Coatings obtained under increased nitrogen pressures are characterized by a hardness of 30 to 40 GPa and Young's modulus of about 600 GPa. Using the increased nitrogen pressures it is possible to form droplet-free coatings on the back surfaces of small articles without the aid of plasma filters.