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A transition border between macroscopic and nanoscale states of solids associated with change of its physical properties is certain to exist. The change of mechanical, magnetic, thermal and other properties of nanoparticles may be due to the surface tension, decrease in coordination number in the top‐surface layer, rebuilding of the electron shell structure, change of the symmetry group of the crystal lattice and the binding energy. Different defects of the structure can also have significant influence on the physical properties of nanoparticles. A violation of the Neumann principle with decrease of the crystal sized is constant discussed in the literature. In the present work the dependence of elastic module, Debye's temperature, melting point, thermal expansion coefficient, magnetic structure on a size of metal nanoparticles (first of all iron nanoparticles) is discussed. On the basis of the obtained results the scale border between nano‐ and macroscopic states is justified. In the present work the peculiarity of the physical processes (melting, diffusion, defects complexes formation) occurring in nanoparticles and nanomaterials is discussed. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Phase and element composition, microhardness of Ti-6Al-4V titanium alloy, Ti/Ti-6Al-4V and Zr/Ti-6Al-4V systems treated by compression plasma flows have been investigated in this work. X-ray diffraction, scanning electron microscopy, energy-dispersion X-ray microanalysis and Vickers microhardness measurements were used for samples characterization. The findings showed that treatment of the "coating/titanium alloy" system by compression plasma flows allowed decreasing the toxic elements (Al, V) concentration in the surface layer of Ti-6Al-4V titanium alloy. The variation of the energy absorbed by the surface layer resulted in the change of the element concentration and the formation of a number of phases in the modified layer: a solid solution on the basis of α' phase in Ti-6Al-4V and Ti/Ti-6Al-4V systems and β phase in Zr/Ti-6Al-4V system. The formation of δ-TiN x at the surface due to interaction of surface layer atoms with nitrogen atmosphere in the vacuum chamber was also found. The change of phase composition and quenching effects resulted in the microhardness increase.