|
|
Changes in structure and phase composition in the surface of tram rail
Švábenská, Eva ; Roupcová, Pavla ; Schneeweiss, Oldřich
We have investigated structure and phase composition of surface layer of tram rails after long time running and the results were compared with those obtained on the original part of material. Changes due to effects of severe plastic deformation together with thermal shocks by friction process were expected. The information about structure and phase composition was obtained by optical and scanning electron microscopy, X-Ray Powder Diffraction, Mössbauer Spectroscopy and Glow Discharge Emission Spectroscopy (GDOES) and this was completed by microhardness measurements. The results show that the surface layer in comparison with the original material exhibits important changes in grain structure, an increase in microhardness and high content of iron oxide and hydrooxides. According to the depth profile of the chemical composition measured by GDOES there is an increase in carbon content in the surface layer which can be effect of up-hill diffusion.
|
|
|
Analysis of nanoparticles released from the car brakes
Švábenská, Eva ; Roupcová, Pavla ; Schneeweiss, Oldřich
Our research is focused on the phase, structure and chemical analysis of the powder particles released by braking of cars from their brake components – discs and pads. The basic information on structure and phase composition was obtained by X-Ray Powder Diffraction, Mössbauer Spectroscopy and scanning electron microscopy with EDX. The results of the particle analysis are compared with materials used for manufacturing brake components and with the powder prepared by ball milling of the mixture of the pad composite and disk steel. Most of recognized nanoparticles are based on carbon, silica/silicates and iron oxides. Their effects on street environment are mentioned.
|
|
|
Analysis of the surface layer of the brake disk
Švábenská, Eva ; Roupcová, Pavla ; Podstranská, Ivana ; Petr, M. ; Filip, J. ; Schneeweiss, Oldřich
Our research is focused on the changes in thin surface layer of the brake disk due to the impact of severe plastic deformation and heating by friction process. The aim of this study is to compare structure, chemical and phase compositions of the surface layer in depth up to several hundreds of nanometers in the no affected central part of brake disk and the part which was in contact with brake pads by braking. The basic information on structure and phase composition was obtained by optical and scanning electron microscopy, X-Ray Powder Diffraction and Mössbauer Spectroscopy. The thin surface layer was studied using Conversion Electron Mössbauer Spectroscopy and X-ray Photoelectron Spectroscopy. We explain the observed changes with the knowledge on effects of plastic deformation and/or diffusion of alloying elements in the material of the brake disk.
|
guest ::
