The paper describes the impact of multi-pollution of atmosphere on carbon steel construction material in Slovak Republic. Corrosion like one of the most decisive factor determining the lifetime of material increases the risk of failure, which has considerable impact on maintenance costs. The objective of the article is to calculate potential material losses of carbon steel using the dose-response functions derived from the results of outdoor exposure program and by STN EN ISO 9223. The values were calculated and compared from 2003 to 2014. For comparison the impact of air pollution and climate condition maps of the mass loss and maps of the corrosion rate were created using 4-year averages - dates (2003-2006, 2007-2010 and 2011-2014). Actually, map of corrosion losses does not help to protect materials, but it can be useful for prediction of risks by design and analysis.

SummarySurface conditions of materials affect the chemical, physical and mechanical properties of stainless steels. The main interest of this paper is to focus on corrosion properties of the AISI 316Ti stainless steel treated by shot peening and shot peening and pickling. In the last years shot peening has been widely used as a method improving fatigue properties of components under cyclical load. Because surface finishing has strong effect on corrosion susceptibility of stainless steels, e. g. pitting and created pits can initialize cracks, it is important to analyse corrosion behaviour of the material in question. In this study, the tested surfaces were characterized by SEM, EDX analyses, measurement of surface free energy and roughness. Corrosion properties were investigated in various environments by exposure, potentiodynamic cyclic and EIS tests.

Large number of mechanical and chemical surface pretreatment techniques is actually used on steels in industrial practice. Choosing the right combination of these technologies is one of the most important tasks for many applications. The purpose of this research was to evaluate the influence of selected mechanical surface preparation methods (grinding, sandblasting) on the quality and electrochemical corrosion characteristics of S355J2 steel before and after the final chemical surface treatment by the technology of manganese phosphating. The surface morphology of the formed phosphate layer was evaluated by a scanning electron microscopy (SEM) and the cross section analysis was performed by a light metallographic microscopy. 0.1M Na2SO4 solution simulating aggressive industrial pollution was selected for electrochemical corrosion tests. Impact evaluation of various mechanical and chemical surface treatments on the corrosion properties of the tested steel was realized by potentiodynamic polarization tests (PD) and electrochemical impedance spectroscopy (EIS) using the Tafel analysis and equivalent circuits method respectively. The obtained results proved that sandblasting negatively affected the corrosion resistance of S355J2 steel and subsequently created manganese phosphate layer.

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Tribological properties of Al-brass pipes of various producers were studied in different environments. The tested brasses have very similar chemical composition, but they differ in microstructure due to mainly by heat treatment after cold drawing. Microstructure as well as roughness of surface influence chemical and mechanical properties which are important in operating conditions. The experiments of tribological behavior were made in various environments, dry air, cooling treated water and 3.5 % solution of NaCl at room temperature 21 ± 2°C. The tribological tests were carried out on the Linear Tribometer at normal loading 5 N by the method ball on plate for the duration of 5500 s. The measured friction coefficients were evaluated by the program DIAdem and the diagrams were created from signal generated by software NSignal Express