Influence of Different Type of Irradiation to Carbon Nanotubes
581
The stability of materials and components of onboard equipment to the influence
of the surrounding outer space plays an important role in ensuring the trouble-free
operation of spacecraft. More than half of refusals in the operation of onboard equipment are due to the influence of the factors of outer space: electron fluxes, cold and
hot cosmic plasma, solar electromagnetic radiation, meteoric matter, solid particles
of artificial origin (space debris), etc. [12]. Analysis of the statistics of the conditions for the occurrence of anomalies in the work of spacecraft shows that in most
cases failure and failure are due to the influence of cosmic radiation on materials and
elements of space equipment [13].
The radiation impact on the spacecraft is due to electrons and ions with energy
10
3 –10
6 eV capable of penetrating depths of more than several tens of micrometers,
causing in the volume of matter ionization of atoms, the formation of local electrical
charges, the formation of defects, nuclear transformations, etc.
Radiation effects are any changes in the structure, properties, state of a substance
or material caused by the action of radiation. Such conversions may have a reverse
and irreversible character. The most sensitive to the effects of cosmic radiation are
semiconductor and optical materials, to a lesser extent polymeric materials, the most
resistant to radiation exposure are metals [14].
Radiation effects arising from ionizing radiation in nanostructures have a number
of peculiarities in comparison with similar effects in objects whose sizes lie in micro
and macro ranges.
Most nanocomposites have a higher radiation resistance relative to the various
components of cosmic ionizing radiation compared to traditional composite materials, but the amount of these data is currently insufficient.
The high radiation resistance of nanocomposites is due to the physical model,
which is based on the notion of a less dense, compared with bulky bodies, anisotropic
packaging of atoms in the CNT and the adsorption surface of the tube with carbon
atoms that it is bulging [15]. Migration processes lead to the healing of radiation
defects [16]. CNTs are able to shield electromagnetic radiation due to high strength
characteristics and to remove thermal loads, static voltage charges due to high heat
and electrical conductivity [17]. It is obvious that during the interaction of an electron
or an ion with the sufficiently high energy characteristic of cosmic radiation, only
very small energy of the incident particle is transmitted to nanoparticles [18]. In a
nanosized object, there is a small number of additional charge carriers or structural
defects. At the same time, with increasing energy of the flying particles, the number
of created carriers and defects will decrease in line with the decrease of the linear
transmission of energy. By contrast, in conventional bulk materials, the total number
of charge carriers and structural defects increases with increasing energy of flying
particles if their run is invested in the linear dimensions of the object.
Figure 1 shows electron microscopic images of CNTs containing inside the catalyst (a) and the microstructure of the catalyst Al 2 O 3 –Fe 2 O 3 –MoO 30,21 in the initial
state (b)
581
The stability of materials and components of onboard equipment to the influence
of the surrounding outer space plays an important role in ensuring the trouble-free
operation of spacecraft. More than half of refusals in the operation of onboard equipment are due to the influence of the factors of outer space: electron fluxes, cold and
hot cosmic plasma, solar electromagnetic radiation, meteoric matter, solid particles
of artificial origin (space debris), etc. [12]. Analysis of the statistics of the conditions for the occurrence of anomalies in the work of spacecraft shows that in most
cases failure and failure are due to the influence of cosmic radiation on materials and
elements of space equipment [13].
The radiation impact on the spacecraft is due to electrons and ions with energy
10
3 –10
6 eV capable of penetrating depths of more than several tens of micrometers,
causing in the volume of matter ionization of atoms, the formation of local electrical
charges, the formation of defects, nuclear transformations, etc.
Radiation effects are any changes in the structure, properties, state of a substance
or material caused by the action of radiation. Such conversions may have a reverse
and irreversible character. The most sensitive to the effects of cosmic radiation are
semiconductor and optical materials, to a lesser extent polymeric materials, the most
resistant to radiation exposure are metals [14].
Radiation effects arising from ionizing radiation in nanostructures have a number
of peculiarities in comparison with similar effects in objects whose sizes lie in micro
and macro ranges.
Most nanocomposites have a higher radiation resistance relative to the various
components of cosmic ionizing radiation compared to traditional composite materials, but the amount of these data is currently insufficient.
The high radiation resistance of nanocomposites is due to the physical model,
which is based on the notion of a less dense, compared with bulky bodies, anisotropic
packaging of atoms in the CNT and the adsorption surface of the tube with carbon
atoms that it is bulging [15]. Migration processes lead to the healing of radiation
defects [16]. CNTs are able to shield electromagnetic radiation due to high strength
characteristics and to remove thermal loads, static voltage charges due to high heat
and electrical conductivity [17]. It is obvious that during the interaction of an electron
or an ion with the sufficiently high energy characteristic of cosmic radiation, only
very small energy of the incident particle is transmitted to nanoparticles [18]. In a
nanosized object, there is a small number of additional charge carriers or structural
defects. At the same time, with increasing energy of the flying particles, the number
of created carriers and defects will decrease in line with the decrease of the linear
transmission of energy. By contrast, in conventional bulk materials, the total number
of charge carriers and structural defects increases with increasing energy of flying
particles if their run is invested in the linear dimensions of the object.
Figure 1 shows electron microscopic images of CNTs containing inside the catalyst (a) and the microstructure of the catalyst Al 2 O 3 –Fe 2 O 3 –MoO 30,21 in the initial
state (b)