Physical Alloying of Plasma Metallization Composite Coating by Allotropic Carbon Nanostructures—Part 2: Analytical Research

We have investigated analytically a possibility of hardening and modifying properties of plasma metallization composite coating (nanocomposite materials) by creating spatial nanolayers of space charge on the surface of nanocrystals by using nanostructures made of allotropic forms of carbon with a high electron affinity. Fullerenes, nanotubes, and other nanostructures of the allotropic carbon forms with the high electron affinity can be used as free electrons' traps that generate a negative charged nanolayer on the surface of the material hardened. These nanostructures (modifiers) attach or capture free electrons and thus charge the crystals of the modifiable material with positive charge. This results in a Coulomb levitation of the positively charged nanocrystals with respect to each other and prevents the recrystallization of the physically doped positively charged nanocrystals in the composite. The remaining part of free electrons increases its kinetic energy near the surface of the positively charged nanocrystal. It changes the physical properties of the nanostructured composite (its strength and luminescence properties). In Pt.1 of this paper, the composite coatings made of copper have been experimentally studied. These coatings do not interact with each other metallurgically. The mechanical properties of Cu:C nanocomposite can be explained by free electrons capture by the carbon nanostructures and the space charge formation. The analytical research of the constricting diaphragm has shown that free electrons traps, distributed uniformly over the nanocrystallites surface, compress the entire nanocomposite into a single whole by the Coulomb forces. The Coulomb compression by such a membrane provides mechanical strength up to 100 GPa. The electric field on the surface of positively charged nanocrystallites can reach 10
¹¹
V/m. This corresponds to the electron energy on the nanocrystal surface of the order of ~10 eV. It enhances the luminescence of nanocomposites.