National Repository of Grey Literature 9 records found  Search took 0.01 seconds. 
Measuring the effectiveness of hydrophobizing product Nanofusion on wood – beech and oak
Machová, Dita ; Zárybnická, Lucie ; Majtás, Dušan
Verification of protective properties and usability of NF Protect Wood for the needs of preservation effectiveness. Moisture, vapour permeability, wettability, water absorption, colour stability were evaluated and a test in climatic chamber was performed.
Corrosion behaviour of hot dip zinc coatings in soil
Kreislová, K. ; Barták, Z. ; Fialová, P. ; Majtás, Dušan
Paper gives some results of corrosion test of zinc coating in soil in the ČR in comparison with contemporary published data. There is given also case study of hot dip zinc coating´s corrosion on specific bridge object.
Corrosion products phase identification using micro-Raman and FTIR
Majtás, Dušan ; Mácová, Petra
Phase identification of corroded metal objects might be problematic because corrosion products are usually a complex mixture of different phases. Furthermore, some of present phases may be either semi-crystalline or amorphous. The most suitable procedure is to use X-ray diffraction (XRD), for identification of crystalline phases in bulk, in combination with micro-Raman spectroscopy to obtain information on smaller scale and given location. Micro-Raman spectroscopy identifies crystalline and semi-crystalline phases. The literature also reports of the application of Mössbauer spectroscopy to identify amorphous phases. In this work, the combined use of Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy is evaluated. The methods may be interchangeable to some point. But is it safe to assume that all phases present can be detected?
Iron alloys outdoor corrosion and laboratory simulation - comparison
Majtás, Dušan ; Mácová, Petra ; Kreislová, Kateřina ; Příhoda, J.
Simulation of iron alloy corrosion is widespread used to predict corrosion resistance. The simulation using corrosion chambers or climatic chambers provides reasonable information on corrosion resistance, the corrosion rate however must be compared to real exposition as the corrosion in simulated environment is accelerated compared to real situation. However the composition of corrosion products and its structure is different question. The corrosion products composition is dependent on corrosion process. The phases present are most likely the same, most voluminous hydrated oxides and oxy-hydroxides on the outside where the less voluminous oxides are present in the lower layers. However this macroscopic phase structure may not fully describe the layered structure of corrosion products, thickness of corrosion products or mechanical properties. In the vicinity of crack in corrosion products the structure is more likely to be similar to the structure near the surface.
Cross-section analysis and mapping using Raman spectroscopy
Majtás, Dušan ; Mácová, Petra ; Kreislová, Kateřina
When dealing with corroded objects, it is necessary to identify the corrosion products to develop a proper treatment for this particular object. Using X-ray diffraction is still suitable to do the phase composition analysis of the material; however it does the analysis of the material in bulk. It is also possible to use SEM to analyze the structure of the corrosion layers on a cross-section by EBSD method; however this method is time consuming. It is more suitable to use Raman spectroscopy when studying the structure of corrosion layers. Using proper equipment, such as Raman microscope it is possible to do not only analysis of precisely given point, but it is also possible to do mapping (both 1D and 2D) of the cross-section. Taking map of surface also does need time, but is definitely less time consuming compared to EBSD method.
Cracking of ferritic stainless steel tubes during production process
Majtás, Dušan ; Kreislová, K. ; Viani, Alberto ; Pérez-Estébanez, Marta ; Geiplová, H.
From the economic reasons many products originally made from austenite stainless steel are nowadays made from ferritic stainless steel. Ferritic steels have relatively low yield strength and the work hardening is limited. They cannot be hardened by heat treatment and only moderately hardened by cold working. Commercially made stainless steel tubes from ferritic steel, used for industrial plumbing was examined on presence of cracks. The cracking was present on the inner side of the convoluted tube shape. The tube manufacturing process consisted of continual bending of the sheet to tube shape, weld the tube, then of cold shaping by pulling through rib-forming frames, which is done in several steps. Then thermal treatment applies to the nearly finished product to remove stress remaining in the structure. Prime suspect was deformation beyond the ductility of used material. However the stress-strain tensile testing does not approved this hypothesis. Several samples of failed material were taken together with reference, and were examined by optical microscopy, and X-Ray Diffraction structure analysis. The structure of the cracked tubes does not show the signs of deformation over the limit, except the location near to the crack itself. Interestingly enough the failed material showed more homogenous structure than the original one. Needle like structures were found when the material is “overetched”, on these structures concentration of stress under bending occur. This structure was identified as δ-ferrite, however its presence in α-ferrite matrix is unclear.
Methods of pitting corrosion evaluation
Kreislová, K. ; Nováková, R. ; Majtás, Dušan
The article describes methods for measuring the depth of pitting corrosion attack. Comparison of digital microscopy and common metallography on sample crossection is made.
Status and other durability glazed roofing church sv. Jakuba Většího in Jihlava. Report to economic agreement with the Czech republic Ministry of Culture
Drdácký, Miloš ; Fabeš, Roman ; Kuznetsov, Sergeii ; Majtás, Dušan ; Šašek, Petr ; Valach, Jaroslav
The aim of the study was to determine the status of glazed roofing church sv.Jakuba Většího in Jihlava and comment on the possibility of another term preservation of the national cultural monument in question. To this end, a local investigation was documented status disorders in selected sections and measured air flow rate. Further samples were taken and covering a series of tests described below.
Cobalt-based ferromagnetic shape memory alloys - preparation, characterization and funtional properties
Kopeček, Jaromír ; Jarošová, Markéta ; Jurek, Karel ; Drahokoupil, Jan ; Majtás, Dušan ; Sedláková, Silvia ; Heczko, Oleg
The cobalt-based shape memory alloys (SMA) are expected to be the new kind of socalled ferromagnetic SMAs. The presented abstract describes the progress on the structural study.

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