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Tantalum nitride coatings possess excellent corrosion resistance, chemical stability, high hardness and biocompatibility. Therefore it can be used as structural elements in integrated circuits (diffusion barrier layer, thin film resistors, mask absorber of X-ray lithography), biomedical material in orthopedics and as wear resistant coating in tribology. In this work thin and thick films of tantalum nitride were prepared by reactive sputter deposition in a Sputron deposition system at a temperature bellow 200°C on polished tool steel discs, polished alumina substrates and silicon wafers. Microhardness, Young modulus and adhesion were measured by nanoindenter and scratch tester. Microstructure and crystal structure were studied by scanning electron microscopy (SEM) in combination with focused ion beam milling system (FIB), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The composition of thin films and chemical states of elements were analyzed by the X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) depth profiling. The roughness and surface morphology were measured by an AFM microscope. Oxidation resistance was studied by heating the samples at temperature of 600-800°C in an oxygen atmosphere for selected times. Specific electrical resistivity was measured by a four-point probe. The electrochemical corrosion behaviour was studied using potentiodynamic polarisation tests and electrochemical impedance spectroscopy (EIS) in a saline solution of 0.5-M NaCl.
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