E. Kutelia; L. Rukhadze; T. Dzigrashvili; O. Tsurtsumia; D. Gventsadze
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 ...
Read More
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.
N.B. Dhokey; S. Ghule; K. Rane; R.S. Ranade
Abstract
Aluminium reinforced with TiB2 is an emerging class of metal matrix composites for many engineering applications such as automobiles, aerospace and naval vessels. The initial part of the present work study involves melting of individual fluxes of KBF4 and KTiF6 in premelted aluminium in an induction ...
Read More
Aluminium reinforced with TiB2 is an emerging class of metal matrix composites for many engineering applications such as automobiles, aerospace and naval vessels. The initial part of the present work study involves melting of individual fluxes of KBF4 and KTiF6 in premelted aluminium in an induction furnace. In the later part of the work covers the combined effect of these fluxes to produce aluminium metal matrix composites containing 2.5% TiB2. The effect of the varying amount of KBF4 on kinetics of TiB2 formation and elimination other unstable phases was studied. The material was examined for hardness, microstructures and wear rates using Pin-on-Disc test machine, XRD and SEM-EDX analysis. The effect of TiB2 on properties was analysed. It was concluded that an optimum level of KBF4 is needed to get critical population of TiB2 particles in the matrix.
)