Plasmachemical Synthesis of Nanopowders in the System Ti(O,C,N) for Material Structure Modification

Abstract

Refractory nanoparticles are finding broad application in manufacturing of materials with enhanced physical properties. Production of carbide, nitride, and carbonitride nanopowders in high volumes is possible in the multijet plasmachemical reactor, where temperature and velocity distributions in reaction zone can be controlled by plasma jet collision angle and mixing chamber geometry. A chemical reactor with three Direct Current (DC) arc plasma jets intersecting at one point was applied for titanium carbonitride synthesis from titanium dioxide, propane-butane mixture, and nitrogen. The influence of process operational parameters on the product chemical and phase composition was investigated. Mixing conditions in the plasma jet collision zone, particles residence time, and temperatures were evaluated with the help of Computational Fluid Dynamics (CFD) simulations. The synthesized nanoparticles have predominantly cubic shape and dimensions in the range 10-200 nm. Phase compositions were represented by oxycarbonitride phases. The amount of free (not chemically bonded) carbon in the product varied in the range 3-12% mass, depending on synthesis conditions.

Synthesis of Superhydrophobic Barium Hexaferrite Coatings with Low Magnetic Hardness

“…A high temperature makes it possible to create a gas phase in a short period of time, and subsequent chemical transformations and condensation make it possible to synthesize nano and micropowders. Consequently, the use of low-temperature thermal quasi-equilibrium plasma is considered to be most optimal in the plasma–chemical synthesis of powders [ 4 , 5 ]. It appears that it is possible to control the degree of influence and structural-phase composition through the duration of plasma treatment, which will allow the control of the properties of coatings of various shapes and morphologies during the recrystallization of surface layers.…”

Plasma-chemical synthesis of highly dispersed core–shell structures from a mechanical mixture of titanium carbide and titanium nickelide

“…По мере перехода температуры кипения жидкий никель активно взаимодействует с тугоплавкими зернами. В этих условиях происходит формирование титан-никелевого нитрида Ti 0,7 Ni 0,3 N [21] в соответствии с теорией зародышеобразования Б. Чалмерса [31], отдельные положения которой приведены в [8] по уравнению реакции TiN y (тв) + Ni (ж) + N 2 ↑ → Ti 0,7 Ni 0,3 N.…”