Solid State Phenomena Vol. 227

Abstract: The paper introduces the experimental corrosion tests that are carried out on the existing weathering steel bridges in the Czech Republic. The influence of the position and location of the surface in the structure on the resulting corrosion rates can be evaluated using this experimental testing. Typical surfaces of steel bridges are tested, e.g. webs of main girders, upper and lower surfaces of flanges, surfaces affected by leaking salt solutions. The corrosion tests to study the relation between steel grade (weathering steels S355J2WP and S355J2W) and corrosion rates are introduced in this paper as well.

Abstract: Most of the modern instrumental methods are mainly applicable only in R&D work. It is shown that some of them could be also used in the field, proving very useful in solving practical corrosion problems. The use of the following methods for testing coatings and substrates are discussed: scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), optical microscopy, Fourier transformation infrared analysis (FTIR), electrochemical impedance spectroscopy (EIS) and differential scanning calorimetry (DSC).

Abstract: The article describes the influence the operating frequency of the transducer on the possibility to detect corrosion using the eddy current method. A bearing ring with two artificially made corrosion defects was used as a test object. The authors determined the characteristics of the defect’s signal value in the function of frequency. The results obtained were then compared to the peak-to-peak value of the signal for a model ring. The tests confirmed the possibility of automatic detection of corrosion on the surface of bearing rings using the eddy current method.

Abstract: In the two last decades, the Electrochemical Microcell Technique (EMT) was used in various electrochemical surface investigations. The diameter of microcapillaries was in the range between few and few hundred microns. This technique was commonly used in corrosion research. Indeed, metallic alloys exhibit a complex microstructure consisting of different metallic and intermetallic phases, inclusions, precipitates... The use of microcapillaries based techniques like EMT makes possible to perform local electrochemical measurements in individual phases. Therefore, it was possible to get information about the behavior of a single grain, inclusion, precipitate... From these information, precursor sites can be identified and criteria leading to corrosion can be proposed.

Abstract: The paper presents a proposed application of the Gunt ET794 turbine model and subsequent tests carried out in order to determine its usability in sample testing under erosive and corrosive conditions. The most important parameter measured during the tests was temperature before the T3 turbine as well as fuel consumption (propane-butane). Following measurement taking and determining conditions, an optimum place for sample attaching was established. CATIA and Autocad software was used to elaborate the sample attachment model. It has been assumed that the tested sample had 14mm in diameter and thickness of 4mm, while the protective coat will be 500μm max. The summary presents additional research and works, whose aim would be to improve the application of the Gunt ET794 as the test stand.

Abstract: The electroless deposition technique was used to obtain Ni-P coatings with various phosphorus content. Machine vision method was applied as a tool for the analysis and interpretation of the data provided by electrochemical impedance spectroscopy (EIS) corrosion studies. The degree of corrosion of the coating surface could be determined by this method. The combination of both methods allows a more complete evaluation of the protective properties of the obtained coatings.

Abstract: The paper presents basic methods of plasma spraying at very low pressure (<2 mbar). Described in the text are conditions which influence microstructure of Thermal Barrier Coatings obtained by these methods. A review and characteristics of the LPPS-TF system applied around the world has been provided.