The main fields of our research group were the development, deposition and characterization of various binary (Cr-C), multicomponent (Cr(C,N), Ti(C,N), (Ti,Al)N), and multilayer (TiN/TiAlN, TiN/CrN) PVD hard coatings. All these coatings were deposited either by evaporation or sputtering at different process parameters (e.g. substrate temperature, bias voltage, partial pressure of reactive gas, deposition rate). The influence of these parameters on the technologically interesting properties such as microhardness, adhesion, corrosion and oxidation resistance was studied and optimal parameters for the deposition of various hard coatings were selected. Emphasis was given on the preparation and characterization of Cr(C,N) and Me-C:H coatings with a high content of carbon and hydrogen. Such composite coatings, which are composed of transition metal carbides and amorphous hydrogenated carbon, have great potential in application, due to its low coefficient of friction. We also developed a new method for study of microcracks propagation in multilayer structures. The research was done also on other fields of thin films and surface physics: a) A study of interface interactions in bi- and multilayer structures (Ni/Cr, Ni/Al, Co/Cu, Al/Si, Al/Fe/Cu) during heat treatment and ion beam mixing. We were successful in preparation of various approximants phases of the quasicrystalline Al62,5Cu25Fe12,5 thin film, which was prepared by heat treatment of Al/Fe/Cu multilayer structure. b) Preparation and characterization of thin electrolyte films of yttria stabilized zirconia (YSZ) and ceria for solid-oxide fuel cells (SOFC). Impedance spectroscopy was also used to determine its the electrochemical properties. c) Development of PVD technologies as an environmentally clean alternative to electroplating and electroless processes. d) The study of corrosion properties and porosity of CrN and Cr(C,N) hard coatings by electrochemical methods (impendance, potentiostatic and potentiodinamic spectroscopies), e) Plasma diagnostics of low-pressure plasma by Langmuir probe and by energy-resolved mass spectroscopy of ions during triode ion plating of titanium and chromium based hard coatings. We found that there is a significant difference in ionization between C2H2 and N2 gases and that the efficiency of ionization of metal and argon atoms depends on the type of reactive gas, while this has an important influence on the physical and chemical properties of hard coatings. More emphasys was given on the decomposition of acetylene into various radicals.