Nanostructured particles of boron, aluminum, and silicon nitrides by thermally coupled SHS reactions of nitriding

Abstract

The paper shows the investigation results of structure and phase formation of boron, aluminum and silicon nitride particles in gaseous nitrogen of high pressure (10–40 MPa) under the terms of thermocoupled high- and low-exothermic reactions (so-called chemical furnaces). In this case the high-exothermic reaction is an additional heat source for the low-exothermic one. The reactions are separated in space and chemically independent. The nitriding terms which are close to extreme ones (high burning temperatures of aluminum, boron and silicon, high heating rates, etc.) provide the reagent evaporation and promote gastransport reactions with the combustion mechanism transition from the solid-phase to gas-phase or vaporliquid due to volatile intermediate products of nitriding and impurities. As a result, the SHS products contain not only well-known forms of nitride particles (nano-fibers, nano-filaments, nano-plates, nano-whiskers, etc.) but such structures as BN nano-tubes with various types of morphology and cubic modifications of BN and AlN as well. It is to be studied additionally.