In this paper, the dependence of magnetic transitions temperatures of nanoporous materials on pore geometric characteristics (volume and shape) have been studied in the framework of the cohesive energy-based model in the case of pure nanoporous nickel and cobalt. Pore geometric characteristics have been taken into account using two parameters: its effective diameter and shape coefficient of a pore which characterizes the degree of deviation of its shape from the spherical one. The estimates allow expecting the possibility to obtain nanoporous macroscopic objects of ferromagnetic materials with a reduced Curie temperature which value also decreases with “complicating” the pore shape.

In this paper, thermodynamical approach has been used to simulate the influence of shape on phase equilibria in the two-phase-region between liquidus and solidus temperatures in case of Si-Ge alloy nanoparticles. Volumes and shapes of considered nanoparticles have been described by their effective radii and fractal dimensions, the dependence of fractal dimensions on temperature has been obtained using a simple geometrical model. It has been shown that decreasing the volume of a nanoparticle and its fractal dimension (which corresponds to nanoparticles of a more complicated shape) leads to narrowing down the temperature range of the heterogeneous region and changes the phase transition temperatures and equilibrium compositions of co-existing phases. At different temperatures, the dependences of the composition of the liquid phase differ which is explained by implementing different mechanisms of reducing the surface energy.