Papers by Author: J.E. Frąckowiak

Abstract: The systematic studies of non-stoichiometric phases from Fe-Al system obtained by selfpropagating high-temperature synthesis (SHS) were the aim of the present work. Investigations were performed using 57Fe transmission Mössbauer spectroscopy. The presence of nonsteichiomertic FeAl, FeAl2 and Fe2Al5 phases was found. It is can be concluded that the studied powder material is in non-equilibrium state. As the result of milling process the contents of FeAl phase increase whereas of FeAl2 and Fe2Al5 ones decrease. The determined crystal structure parameters and the hyperfine interaction parameters are presented and discussed.

Abstract: The Fe-Al-X and Fe-Al-Ni-X (X = Fe,Ni,Cu,Cr) metallic powders obtained by the selfdecomposition method and next intensive grinding in an electro-magneto-mechanical mill were examined by X-ray powder diffraction (XRD). Morphology of powders was determined by scanning electron microscopy (SEM) whereas energy dispersive spectroscopy (EDS) was applied to identify the composition of phases. The FeAlX and FeAlNiX phases both of B2 type structure were found besides small amounts of Al(OH)3 and rest of metallic additions.

Abstract: The influence of a tribological process in the polymer/metal system on changes in microhardness (H) and Young’s modulus (E) of the surface under friction and UHMWPE volume has been studied. Twelve samples of polyethylene characterized by a different degree of initial plastic deformation and different electron irradiation dose were analyzed. For four of the samples a decrease by 5÷10 times in polyethylene degradation has been found. This result is promising in that a prolonged durability can be expected in case of application for endoprostheses acetabular cups. It has been found also that a polyethylene material irradiated after initial prestraining only once shows enhanced micromechanical properties after friction. It has been found that this result was due to reorientation of lamellas on the friction surface taking place during deformation which accompanies the tribological process. It has been proved that the increase of H and E values in the layers situated at a depth of 1.5 mm÷7.5 mm is due to a decrease of the free volume centers in the UHMWPE polyethylene and to an increase of the degree of spatial arrangement of the structure (absorption in crystallinity band of FTIR spectrum).