Production of new nanostructures for modification of steels and cast irons

Abstract

Two new nanoscale materials from silicon wastes were developed. Carbon material consists of a mixture of amorphous nanoparticles with a maximum size distribution of 200-500 nm, aggregated coils of carbon nanotubes about 1% of the volume, globular nanoparticles of a spherical form of crystalline silicon dioxide with a maximum size of 200-300 nm, coated with a carbon shell with a wall thickness of 4-6 nm. Silicate material contains over 90-97% of amorphous silicon dioxide with a maximum size of 200-300 nm, and also contains silicate nanotubes representing silica with a diameter of 50-60 nm. It was determined that the mechanism for the modification of metals and alloys, obtained by nanostructured materials, is formed in accordance with the hypothesis of a local stress field at the ends of the tubes, increasing the rate of formation of the crystallization centers of the melt. An additional modifying effect is exerted by the large surface energy of nanostructured materials, if we compare them with modifying materials that have micron-sized structures.