Nanocomposites and nanomaterials

Formation of structure and properties of wearproof nanocomposites based on silicon nitride applying technologies of electric sintering
Zgalat-Lozynskyy O.B.
Department of Physics, Chemistry and Technology of Nanotextured Ceramics and Nanocomposite Materials, Institute for Problems of Materials Science of the NAS of Ukraine. 3, Krzhyzhanovkog str., Kyiv-03680, Ukraine. 
E-mail: zgalatlozynskyy@gmail.com

Presented investigation is devoted to production of nanocrystalline wearproof ceramics based on high melting point compounds. Nanocomposites based on silicon nitride and titanium nitride are perspective to operate in aggressive environments (acids, alkali) at the elevated temperatures [1]. To improve sinterability of nanopowders the conception of composite nanopowders preparation with an orientation on the further method of consolidation – Spark Plasma Sintering (SPS) or Rate-Controlled Sintering (RCS) has been developed. Mixtures of composite nanopowders were manufactured via chemical synthesis. During the synthesis the surface of basic nanoparticles (e.g. Si3N4) was cladded by component with high sinterability and conductivity (e.g. TiN) [2, 3]. Wearproof nanocomposites in the system Si3N4 – TiN were manufactured by the SPS and RCS technologies. The nanocomposites demonstrated high tribotechnical properties in the pairs of nanocomposite-nanocomposite and nanocomposite-hard alloy (WC-6Co) under conditions of dry friction (k <0,25, specific wear ~ 5·10-8 mm3/N·m). In addition, high stability of mechanical and tribotechnocal properties after the long-term exposition at the temperature of 80oС in H2SO4, HNO3 and NaOH has been studied.

1.	Zgalat-Lozynskyy, N.I. Tischenko, V.T. Varchenko, A.V. Ragulya, A. Polotai Tribological behaviour of Si3N4-based nanocomposites // Tribol. Int. – 2015. – №91. – Р.85-93.
2.	Tishchenko N.I., Kolesnichenko V.G., Dubovitskaya N.V., et. al. Surface modification of silicon nitride nanofibers with titanium nitride particles // Powder Metall Met Ceram . – 2009. – 48, N 11–12.– С. 627-633
3.	Zgalat-Lozynskyy, O.B., Tischenko, N.I., Ragulya, A.V. Spark Plasma Sintering of TiN (Shell)–Si3N4 (Nanofiber) System// Powder Metall Met Ceram .-2018.- 56.-P. 625-632.