Abstract <p>Studies have been carried out of the elemental composition and mechanical properties of AlTiN and AlTiCN coatings obtained by conditions of separation of two-component plasma of a cathode-arc discharge using the magnetic optical system of the UVNIPA-1-001 vacuum machine. Separation makes it possible to reduce the number of macroparticles of micron and submicron sizes in coatings by half. In this case, large macroparticles (more than 5 microns) are removed almost completely, and the number of particles from 3 to 5 microns is reduced by an order of magnitude. A study of the elemental composition of AlTi(C)N coatings revealed a strong deficiency of aluminum in the absence of magnetic plasma separation. At the same time, magnetic separation makes it possible to obtain coatings with a relative content of aluminum and titanium close to the content of these metals in the cathode. As a result, under certain conditions of cathode arc combustion under conditions of magnetic separation of the plasma flow, a superhard AlTiN coating (HV&#xa0;5400) was obtained. It has been shown that the adhesion of coatings during plasma separation can be increased several times by optimizing the nitrogen pressure during their deposition. A physical explanation is proposed for the phenomenon of changes in the elemental composition of coatings under separation conditions based on the nature of the propagation of light and heavy plasma ions in the presence of a curvilinear magnetic field.</p>