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The present work was undertaken to study tribo-induced chemical and structural changes occurred in the MoSe(Ni)/a-C antifrictional coatings formed by pulsed laser deposition under varied conditions. The influence of these parameterson the wear resistance of the coatings was investigated.Keywords: molybdenum selenide, diamond-like carbon, laser deposition, friction, multilayered coatings 1. INTRODUCTION Transition metal dichalcogenide (TMD) films are very promising for solid lubrication. Up to date the tribological functionalities of both MoS2 and WS2 -based coatings are thoroughly investigated. At the same time MoS and WS,,components are used in the coatings of different architecture: 1) single-layer TMD coating" 2;2) combined TMD/hard ceramics double-layer coatings" ' 4; 3) multi-phase composite coatings, containing nanocrystalline TMD5' 6 Molybdenum and wolfram disulfides show the exceptional tribological properties in vacuum and in the inertenvironment. However, their tribological behavior is essentially worse in the oxygen-containing media due to their

The potentially wide range of optical constants obtained from differently deposited carbon layers with diverse atomic structure has been the subject of an intensive research in recent years. The optical properties are well known to depend strongly on the level of contamination and the degree of atomic order in the layer material. The purpose of the present paper is to sum up the results of our investigations of optical and electrical properties of numerous differently deposited carbon layers and to relate them to the results of measurements of mass density, the atomic composition of the layers and electron diffraction measurements. In particular, estimation formulas are provided to relate the IR refractive index to the mass density and the hydrogen concentration of the layers. In addition, special attention is paid to the exponential absorption region.

The optical properties of hard amorphous carbon layers deposited by different techniques (ECR-microwave plasma deposition, dc-plasma deposition, rf-sputtering, and electron beam evaporation) have been investigated from the middle IR up to the visible spectral regions. Refractive indices and absorption coefficient behavior have been determined by means of spectral transmittance and reflectance measurements. ECR microwave and dc-plasma deposited layers show a transparency wind w in the middle IR in the wavenumber range 1700 cm -1 -1 . The refractive indices in the window region are between 1.9 and 2.3 with weak dispersion and show the usual increase of film mass density. However, absorption losses in the window-region are considerably higher than those in the case of diamond. For dc-plasma deposited layers, IR-absorption losses have been discussed in terms of a dispersion model, considering the absorption losses detected to be caused by a superposition of Lorentz lines and an Urbach tail. RF sputtered layers represent some kind of intermediate between graphiticlike layers (deposited by electron beam evaporation) and IR-transparent carbon formations. For rf-sputtered layers, IR-refractive indices show an extraordinary dependence on film mass density, which could be explained in terms of a mixing model, considering these layers to be built from graphiticlike and polymericlike compounds.