Nucleation and growth of carbon nanoforms on the surface of metallic plate-substrates and the mechanism of their doping with the clusters of ferromagnetic atoms  

¹Republic Centre for Structure Researches of Georgian Technical University, 77 Kostava Str., Tbilisi 0175, Georgia

²R. Dvali Institute of Machine Mechanics, 10 Mindeli Str., Tbilisi 0186, Georgia

Adv. Mater. Lett., 2018, 9 (12), pp 867-871

DOI: 10.5185/amlett.2018.2144

Publication Date (Web): Sep 14, 2018

Copyright © IAAM-VBRI Press

E-mail: ekutelia@gtu.edu.ge

Abstract

The present work deals with the special experiments on SEM-EDX study of morphology, chemical composition and topological transformations of the initial ground surface of the bulk iron plate-substrate after its interaction with the ethanol vapor pyrolysis products at high temperatures in the closed-loop and open cycle reactors. Our experiments have shown that the mechanism of formation of Fe clusters-doped CNFs on plate-substrate surfaces may be represented as a process, the first stage of which is a protonation of the substrate subsurface layers caused by diffusion of hydrogen atoms facilitating the formation of 3D nano-groups of Fe atoms assembled in the characteristic clusters with magic numbers of atoms, depending on the thermodynamics of the metal. The spontaneous coalescence of these clusters into giant Fe-clusters at comparatively low temperatures and formation of iron nano-droplets at comparatively high temperatures results in the formation of a nanopatterned surface with the uniformly distributed catalytic centers of CNFs nucleation. The second stage of the process is a nanoparticle-guided growth through the VLS or VS (at low temperatures) growth mechanisms in which the one cluster provides nucleation of only one CNF particle so that the sizes of the nucleation centers determine the basic size of the CNF nanoparticles.

Keywords

Doped CNFs, clusters, growth mechanism, metal plate-substrate, SEM-EDX.