Nanocomposites and nanomaterials

Ti-Ni based nanocomposites produced by spark erosion method
Gilchuk A.V.1, Monastyrsky G.E.1
1 National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”. 37, Prosp. Peremohy, Kyiv, 03056, Ukraine. 
E-mail: a.v.gilchuk@gmail.com

Interest to the nanocomposites based on well-known Ti-Ni shape memory alloy increases. For example, core-shell like structures Ni@Ti, Ni@TiO2 and NiO@TiO2 can occur during Ti-Ni nanopowder production [1]. Such nanocomposites can be used potentially as additional layers for solar cells efficiency increasement and as photocatalysts for H2 generation.
A few types of nanoparticles can be formed during spark erosion of Ti-Ni-based alloys in cryogenic liquids [2,3]. The morphology and fine structure of the nanocomposites were investigated by transmission electron microscopy (TEM), high-resolution (HRTEM) and energy-filtered (EFTEM) transmission electron microscopy. The elemental composition was measured by energy-dispersive X-ray spectroscopy (EDX). The finest fraction (5-20 nm) consists on the mixture of TiO and NiO. At the same time, “core-shell” structures were observed in particles from tens to hundreds of nanometers in size. The core-shell nanocomposites have FCC structure. The core composition is close to the eutectic between the Ni and Ni3Ti. The shell composition is almost TiO. The formation mechanism of the spark eroded Ti-Ni based nanocomposites, ways for output increasement and possible fields of application are discussed. 

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2.	Monastyrsky G.E. Nanoparticles formation mechanisms through the spark erosion of alloys in cryogenic liquids // Nanoscale Research Letters.-2015.-10, N 503.-P. 1-8.
3.	Monastyrsky G.E., Kolomytsev V.I., Koval Yu.N., Ochinn P., Wang G., Ivanova O.M, Danilenko N.I. Structure investigations of Ti-N-Hf based shape memory alloy powders produced by spark erosion method in liquid argon // Metallofiz. Noveishie Tekhnol.-2011.- 33, N 3.-P. 289-300.