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This paper presents the results of investigation of four cast alloys based on the FeAl intermetallic phase. Microstructure tests using light microscopy, electron scanning microscopy and X-ray diffraction methods, have been performed. On this basis, a presence of particles rich in zirconium and molybdenum, and in case of the alloy with 28 at.% aluminium and 5 at.% chromium - the presence of sigma phase (FeCr), has been found. Also, the results of the study of the microstructure influence on the electrochemical corrosion resistance in the 5 % NaCl solution have been presented. The Fe-26Al-2Cr-1Mo-0.1Zr-0.005B at.% and Fe-26Al-5Cr-1Mo-0.1Zr-0.005B at.% alloys exhibited increased corrosion resistance in comparison to the Fe-23Al-1Mo-0.1Zr-0.005B at.% alloy without chromium addition. The appearance of the sigma phase in the alloy of Fe-28Al-5Cr-1Mo-0.1Zr-0.005B at.% chemical composition resulted in lowering the corrosion resistance of this alloy and a change in corrosion character from the pitting to the intercrystalline one. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents the results of metallographic examination of microstructural changes in the matrix of γ–γ′ superalloy Inconel 713C, subject to electron beam fusion. The obtained fusions simulate the phenomena that occur in the weld and the heat-affected zone during welding. Changes of γ′ phase morphology in the fusion zone, in HAZ and in the areas adjacent to grain boundaries that can affect crack initiation were determined. Changed morphology in the recrystallized γ′ zone can result from its reduced melting point due to impoverishment in niobium and titanium as well as to changed aluminium concentration or accelerated diffusion of alloying elements. The cracks found in HAZ propagate mainly through grain boundaries in the microporosity areas or, possibly, the areas left by molten carbide phases. However, no secondary phases with lower melting point or eutectics like (γ–γ′) (M x C y +Zr+Si) were found in the neighbourhood of cracks. The cracks present in the fusion zone were initiated at high temperature and propagate in the areas of interdendritic voids. The cracks were caused by the high solidification rate in the fusion zone and low thermal conductivity of the alloy. [Copyright &y& Elsevier]

Submicron silica spheres containing silver nanoparticles on their surfaces have been obtained by the sol–gel technology. The silver-doped matrices were immersed in solutions of various substances enabling the solute molecules to interact with surfaces of the Ag0-doped silica spheres. Raman spectra of the Ag0-doped matrices after impregnation in solutions of the solute molecules have been measured. The impregnated silica matrices which did not contain silver nanoparticles were used as a reference. These experiments have been performed in order to establish whether Raman signal enhancement could be obtained by adsorption of various solute molecules on the surface of Ag0 inclusions in the sol–gel matrices analogously to the standard surface-enhanced Raman spectroscopy (SERS) method. [Copyright &y& Elsevier]

Abstract: We report on magnetic behavior of the electromagnetic compatibility (EMC) compound FF6.2 and composites prepared by the modified Stöber method using FF6.2 as the magnetic ion-containing (Fe2+/Fe3+) precursor. The composites were characterized by the X-ray diffraction analysis (XRD) and morphology of the magnetic powders was investigated by a scanning electron microscope (SEM) and a high resolution transmision electron microscope (HR TEM). Magnetic properties of the materials were studied by measurements of the magnetization, AC susceptibility and Mössbauer spectra. [Copyright &y& Elsevier]