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The purpose of this study was to investigate (simulation of environment for salt treatment of roads in winter and the simulation of the environment of condensed exhaust gas) the galvanic corrosion phenomena which can exist in the construction coupling of cars. The electrochemical behaviour of the hot dip galvanized steel and aluminium alloy, stainless steel and aluminium alloy and stainless steel and silumin which were investigated by electrochemical methods in 3 % NaCl solution and in SEG solution. The open corrosion potential measurement was used to obtain the values of the potential for each couple. The measurement showed a greater bimetallic risk for hot dip galvanized steel with aluminium alloy, where there was ΔESCE > 500 mV and this couple is not suitable either for use in aggressive environment. Calculation of the rate of corrosion attack results from the determination of corrosion currents as measured by Taffel and Evans. The extent of corrosion damage was analysed by means of a light microscope. Keywords: bimetallic; aluminium alloy; stainless steel; silumin; exhaust gas; corrosion potential; electrochemical method;

Four hard thin coatings (TiSiN, TiN-CrN multi, AlTiN a WC) were deposited on the WC+Co substrate by cathodic arc deposition. Adhesion test of PVD coatings was evaluated by comparison failure of coating surfaces. The surface features after the Rockwell indentation test were examined by light microscopy. The results showed that the AlTiN and WC coatings exhibited acceptable failure and are appropriate for usage in practice. Unlike them, had TiSiN and TiN-CrN coatings poor adhesion, which resulted in unacceptable failure after Rockwell C test.

Steam superheaters are used to increase the temperature and transport the flowing superheated water vapor before it enters the steam turbine. Creep-resistant steels with required high resistance to high-temperature oxidation are used for production of superheaters. The elimination of the protective oxide layer formation on the steel surface limits their upper application temperature in a water vapor containing environment. In this paper, the oxidation behavior of MarBN (MARtensitic 9Cr steel strengthened by Boron and MX Nitrides) steel exposed for 1000 h at 600 and 650 °C in a mixed atmosphere of air + 10% water vapor was analyzed. The oxidation mechanism was discussed on the basis of oxidation kinetics, morphological observations, microscopic and XRD analysis of the oxide layer. The oxidation kinetics was governed by the parabolic law. SEM analysis and XRD analysis showed that the outer steel oxide layer after 1000 h exposure at 600 °C was mainly composed of hematite Fe2O3and a small proportion of Cr2O3. The inner oxide layer was composed of (FeMnCr)2O4and Cr2O3. The steel surface after 1000 h of oxidation at 650 °C, the outer oxide layer consisted of hematite Fe2O3, Cr-rich phase and magnetite Fe3O4, and the inner oxide layer was mainly iron-chromium-manganese spinel (FeMnCr)2O4.