Solid State Phenomena Vol. 114

Abstract: Nano-composites consisting of a primary matrix phase of hard nanocrystalline SiC and a secondary nanocrystalline GaAs semiconductor phase were obtained by high-pressure zone infiltration. The synthesis occurs in three stages: (i) at room- temperature the SiC nanopowder is compacted under high pressure to 8 GPa, (ii) the temperature is increased to 1240°C, above the melting point of GaAs, and the pores were filled with liquid, (iii) on cooling GaAs nanocrystallites grow in the pores. The synthesis was performed using a toroid-type high-pressure apparatus (IHPP PAS, Warsaw) and a six anvil cubic press (MAX80 at HASYLAB, Hamburg). X-ray diffraction studies were performed with a laboratory D5000 Siemens diffractometer. The phase compositionn, grain size and macrostrains in the synthesized materials were examined. The microstructure of the composites was characterized using a Scanning Electron Microscopy (SEM), and High Resolution Transmission Electron Microscopy (TEM). Far-infrared reflectivity and Raman spectroscopy measurements were used to trace built-in strains.

Abstract: Metal particles of silver (Ag) and copper (Cu) have been synthesized in the presence of Aerosol-OT (AOT) or fluorinated surfactants in water-in-scCO2 microemulsions by the chemical reduction of AgClO4 and Cu(ClO4)2. The formation of Ag particles by the photo-reduction using UV-light have been confirmed by in-situ UV-Vis, X-ray absorption fine structure (XAFS), and small angle X-ray scattering (SAXS) measurements. Cu particles have also been prepared by the addition of a reducing reagent sodium borohydride, and the electronic structure of Cu ionic species has been investigated after reduction in the water-in-scCO2 microemulsions. The average size of aggregates of Ag particles in the microemulsions by means of in-situ SAXS measurements also has been estimated.

Abstract: X-ray investigations revealed that the increase in the applied pressure during high pressure torsion (HPT) of commercially pure Ti leads not only to substructure refinement with an increase of the dislocation density and microstrain level but also to an α→ ω phase transition at room temperature. The coexistence of both α and ω phases, the latter known as a high pressure phase, in the ratio approximately of 1:3 has been obtained after removal of thehigh pressure. Texture analysis of electodeposited Ni after HPT discovered a new form of crystallite orientation distribution in the nanocrystalline state. A nearly random orientation crystallite distribution has been observed unlike the “traditional” case of a shear texture forming in cubic symmetry metals. The crystallographic texture data obtained were considered as experimental evidence of the changed plastic deformation mechanisms in nanocrystalline Ni produced by HPT.

Abstract: The texture of Al – 0.7 wt. % Li alloy processed by two different methods of severe plastic deformation (SPD) has been investigated by X-ray diffraction, and analyzed in terms of the orientation distribution function (ODF). It was found that severe plastic deformation by both Equal Channel Angular extrusion (ECAE) and Hydrostatic Extrusion (HE) resulted in an ultrafine grained structure in an Al – 0.7 wt. % Li alloy. The microstructure, grain shape and size, of materials produced by SPD strongly depend on the technological parameters and methods applied. The texture of the investigated alloy differed because of the different modes of deformation. In the initial state the alloy exhibited a very strong texture consisting of {111} fibre component. A similar fibrous texture characteristic was also found after HE whereas after the ECAE the initial texture was completely changed.

Abstract: Current and prospective trends in application of metallic nanomaterials have been studied. The study has been conducted within the Nanoroad SME European project – as the first step for a roadmap for industrial application of nanomaterials. The web page of the project is http://www.nanoroad.net/. The present report presents an analysis of patents, papers, national and European projects in the field of nano-metals, and also an analysis of the present state of research and expected trends in this domain. Based on the performed analysis a data base of nanomaterials has been developed as well as roadmaps with expected time to applications. It can be found under http://bourgogne.arist.tm.fr/nanoroadsme/home/. The roadmap is mainly addressed to SMEs to help them to decide about applications or production of nanomaterials.