Plasma-chemical
synthesis method of nanostructured materials for space-rocket engineering G.G.Raykunov, G.N.Zalogin,
A.V.Krasilnikov FGUP One of the most
perspective directions for goal technologies realization in space-rocket
engineering is nanostructure materials using. In space-rocket engineering the
possible applications of nanomaterials and containing such materials coverings
are next: ·
reduction of the
onboard equipment weight and reduction of power supply at the expense of
element base using on the basis of carbon nanomaterials in microelectronics; ·
increase of solar
batteries efficiency for the bill improvement of silicon production processes
and drawing; ·
expansion of
solid fuel burning speed regulation limits and decrease of a specific pulse
loss in the combustion chamber of the rocket engine at the expense of
application in fuel of nano dispersion metal combustible (aluminum, magnesium,
borum, their alloys and updating); ·
increase of the
constructional materials durability characteristics by addition carbon
nanotubes; ·
improvement of
manned space ship life-support systems by filters development with titanium
nanodioxed (ТiO2)
using for liquids clearing; ·
increase of space
ship friction units normal functioning (for example, in devices of solar
batteries disclosing), at the expense of the nanomaterials additives in greasing
or coverings drawings (switching nanodiamond) on dry friction units; ·
increase constructional materials heat durability and
heat-resistant for the bill by more heat-resistant materials drawing on their
surface (such as carbides WC, NiC, MO2C, TaC, SiC, nitride BN or
carbon-metal composites and firm alloys Сu-C, Ni-C, WC-CoC etc.); ·
change of the
space vehicles reflecting and absorbing characteristics in UV, IR and
radar-tracking ranges of waves lengths by drawing nanomaterials multifunctional
coverings. The development of technologies
using nanomaterials restrains because of absence opportunities of their
production in enough. Well recommending themselves in laboratory researches the
ways of carbon nanostructure production (fullerenes, nanotubes etc.) based on
use of an electrical arch and laser evaporation have a lot of lacks and do not
give in to scaling on productivity of process. A small temperature way of
carbon nanotubes (CNT) production - chemical deposition method from pair based
on carbon hydrogen decomposition (for example, acetylene) on catalysts (Ni, Co
etc.), requires careful substrates manufacturing with the nanostructured
catalyst. Very promising in this respect is the
plasma-chemical method for of nanostructured materials synthesis using the
heating and sublimation, or decomposition of precursors in the high-frequency
induction plasma gas discharge. The advantages of the proposed method in
comparison with the common arc method are: -
no
restrictions on deposited power and the consequent possibility of a substantial
increase in productivity; -
ability
to work with the precursors in different states of aggregation (powders, gases,
liquids); -
easy
to prepare mixtures of starting materials with catalysts; -
passage
of the nanostructures formation outside the zone of high frequency
electromagnetic fields and radiation level influence; -
the
possibility of the main parameters remote diagnostics determining the formation
of nanomaterials, in particular, the spectral gas temperature measurements and
composition of the mixture (through a window available in the working part of
the installation); -
opportunities
to optimize the process by an independent control of pressure, energy input and
expenditure ratios plasma gas, carbon-containing substances and catalyst; -
quasi
(outside the discharge zone) and the laminar flow, which makes it possible
reliably to calculate parameters of the gas with the vapor source material at
all stages of the movement, including the boundary layer on the cooling water soot
trap; -
the
possibility of flow forming using various additional devices (nozzles) and by
changing the geometrical parameters (in particular, the distance from the
inductor to soot trap). This allows to get in the plasma flow containing a pair
of carbon and a catalyst of sufficient length with a high vapors concentration
and optimal values of temperature and pressure for the nanostructures
formation. Compared to electro arc plasmatrons
which are also used in plasma chemical processes, but in the workflow where
there are impurities erosion products of the electrodes (copper or tungsten), HF-plasmatrons
can obtain chemically pure plasma flows and high-purity nanomaterials
synthesis. Key challenges in development of the most
promising nanotechnology, using the approach bottom-up-assembly of
nanomaterials at the atomic or molecular level (fullerenes, carbon nanotubes,
nanopowders,etc.), are next: determine the most optimal in performance terms
and energy cost of initial material transfer in an atomic or molecular state; establish
a condensation and trapping process of the resulting product from vapor. Research to test the methods of nanomaterials
obtaining and nano plasma enhanced deposition method is carried out using both
experimental techniques and methods of mathematical modeling and optimization of
nanomaterials formation processes. The principle of plants with high frequency gas
heating based on the known physical phenomenon of heat conductive medium
electric current induced in them by alternating electromagnetic field. In HF-plasmatrons
such a heated conductive medium is an ionized gas. An alternating
electromagnetic field is created inside the inductor, under the influence of
this field free electrons available in the gas is accelerating. Acquired by an
electron energy is large enough, part of this energy is transferred to
molecules in collisions, causing the heating of the gas. In this regard, in the
zone of discharge there is a considerable difference in temperature of
electrons and heavy particles. As the distance from the inductor and increasing
the pressure, this difference decreases. High temperature gas T ~ 10000 K can
disperse up to the atomic state, even the most refractory material. A more
detailed description of the flow in the RF plasma torch can be obtained by
simultaneous solution of equations of gas dynamics, taking into account the
real gas properties and the Maxwell equations. The experimental and theoretical study of the
nanomaterials synthesis by plasma chemical method in plasma flow generated in
the HF plasmatron showed that: -
use
of high-frequency plasmatrons in nanotechnology to produce nanomaterials and
coatings is a very promising area of research; -
power
density (specific heat flow) is supplied to the powder particles in the plasma
flow can be up to 20 MW/m2
and more that can vaporize carbon particles, and the most high melting metals,
alloys, ceramics, etc.; -
the
effectiveness of the carbon particles sublimation process increases with
increasing input energy (plasma temperature), gas pressure, using the
plasma-forming gases with lower molecular weight and with particle size powder
decreasing; -
flow
near carbon particles with a diameter less than 30 microns is the free molecule; -
collisions
of carbon particles or other material between them can be neglected; -
carbon
particles or other substances processed at a time heated evenly, the amount of
radiation energy absorbed by the particles is small compared with the radiated
one and the integral emissive of the
material has little effect on the particles temperature; -
carbon
flux of molecules incident on the carbon particle from the gas phase is small
compared with the flow of sublimated carbon molecules. The use of plasma-chemical nanomaterials production
method and the use devices with high-frequency plasmatron of high power for its
implementation will allow to develop a competitive industrial scalable
technology to meet the increasing nanomaterials demand. The universality of the
plasma method of materials dispersing enables the use of the installation of
such type as to produce various nanomaterials and coatings. Gennadiy Gennadyevich Raykunov, General Director (Central Research Institute
of Mechanical Engineering - "TsNIImash"); graduated from Volgograd Polytechnic
Institute (1975); Doctor of technical sciences, Professor, Academician,
Vice-President of K.E.Tsiolkovskiy Russian Academy of Cosmonautics (TRAC), Head
of "Space Mechanical Engineering and Design of Space Systems" section and
"Space Mechanical Engineering and Design of Automatic Space Vehicles"
department of TRAC, the first Vice-President of Moscow regional TRAC
department, Honoured mechanical engineer of the Russian Federation, Honoured
tester in space engineering. G.G.Raikunov is a famous scientist in the fields
of system analysis, space and rocket systems of special purpose, ballistic
support of flights, design, construction and experimental testing of
rocket-and-space systems, complexes and facilities of civil and strategic
purposes. He has developed a new scientific direction based on the system
approach to complex application of aerospace, geophysical and geological
information to solution of natural resource problems. Scientific results of his
works have been published in 118 scientific papers, reported at 21 conferences
and stated in more than 250 scientific reports. Georgiy Nikolaevich Zalogin, Chief scientific associate ("TsNIImash"), graduated from Moscow
Institute of Physics and Technology (1963, engineer in physics); Doctor of
technical sciences, Laureate of the National Prize of USSR in science and
engineering (1998); Corresponding Member of K.E.Tsiolkovskiy Russian Academy of
Cosmonautics. He participated directly in tryout of a large
number of space engineering products. During "Buran" project he conducted
extensive experimental research in HF plasmatron. Since He has published 131 papers (3
monographs, 124 journal articles and papers in conference transactions, 3
invention applications, and 1 patent). Arthur Vladimirovich Krasilnikov, Chief scientific associate ("TsNIImash"), graduated
from Moscow Institute of Physics and Technology (1965, department of
aerophysics and applied mathematics, specialized in flying vehicles); Doctor of
technical sciences, member of Scientific Councils of "TsNIImash" and Joint
Institute of High Temperatures of RAS, Academician of K.E.Tsiolkovskiy Russian
Academy of Cosmonautics, Fellow of American Institute of Aeronautics and
Astronautics, Laureate of N.E.Zhukovskiy Prize, S.P.Korolev medal and
Yu.A.Gagarin medal. Participated directly in theoretical and experimental
studies, design, production and implementation of "TsNIImash" experimental
base, with support of a large number of experiments conducted on different
aerodynamic plants, plasmatrons and shock tubes. He has published 103 papers,
including 7 monographs and 5 invention certificates. |
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