Modern iron nanoparticles production methods for steel modification

The development of physical methods of high-energy impact on the material makes obtaining a substance in a nano-dispersed state possible. The difference between nanoparticles obtained by the electrospark method, when condensation of the metal vapor phase occurs in a dispersion medium (water), the temperature of which does not exceed 30-40 degrees C, is a relatively narrow distribution of particles of the dispersed phase (20 - 100 nm). The field of application of such substances is not limited to agrobiological purposes. The authors investigated the electrospark metal granular dispersion method in an aqueous medium. The particles obtained by the above method have a size of 20-100 nm and several competitive advantages compared with similar methods of synthesis of metal nanoparticles. The level of defects in the crystal structure of nanoparticles after electro spark treatment is significantly higher than the values achieved by known methods of hardening metals and alloys. The high level of dislocation density in nanoparticles determines their high energy saturation. The study of the fine structure showed that the level of dislocation density in nanoparticles is close to the limit values of 1014 cm-2 as a result of the joint action of shock waves that arise in the process of pulse expansion of electric spark channels under the influence of pressure of several hundred atmospheres, high cooling rate of more than 103-104 °C/s. Analysis of the internal structure of the obtained nanoparticles shows that their composition is heterogeneous. The particle is a metallic nucleus on which an oxide film is formed. In addition, iron particles can have a complex phase composition, namely, contain (consist of) alpha-iron and gamma-iron, which further expands the physical and technological aspects of using particles with a sharply non-equilibrium structural and phase composition.