Liudmila O. Root

Growth of aluminum nitride single crystals under thermal explosion conditions

The process of aluminum nanopowder combustion in air under thermal explosion conditions has been studied. It is established that the presence of a constant magnetic field with an induction of 0.4 T favors the formation of aluminum nitride single crystals under non-steady-state combustion conditions.

The rise of energy accumulated in metal nanopowders

The influence of nanopowder irradiation by fast (4-MeV) electrons on the energy stored in nanopowders is studied. It is found that the irradiation of the nanopowders increases the amount of accumulated energy by 2.5 times as a maximum compared with the thermal effect of nonirradiated nanopowder oxidation.

Scientific research on nanopowders diagnostics

The four parameters of chemical activity are proposed in the paper for testing of metal nanopowders and their mixtures stability to oxidation and chemical interaction. For estimation the thermodynamic conditions of the “metal nanopowder-gas” systems it is suggested to investigate their electrochemical characteristics.

Measuring the Changes in Copper Nanopowder Conductivity during Heating as a Method for Diagnosing its Thermal Stability

This work researches the impact of the temperature of compacted copper nanopowder on the amperage of the current flowing through the nanopowder sample. It was determined that upon reaching its oxidation temperature (~ 1900C), the copper nanopowder started conducting electricity, and at 280-320°C electric breakdown of sample was occurring. This is caused to irreversible processes taking place in nanomaterials during heating, such as sintering and mass-transfer, those processes leading to the formation of conductivity channels. This speaks in favor of an evident dependency between copper nanopowder conductivity and the chemical transformations taking place in it; this allows for recommending this research method for instant diagnostics of copper nanopowders.

Application of Aluminum Nanopowder for Pure Hydrogen Production

The problems of hydrogen energetic as well as a method of high pure hydrogen obtaining are presented in the paper. It was suggested to use the reaction of aluminium nanopowder with water, as the reaction proceeds with high rate even at ambient conditions (the rate of hydrogen emission reached 18 ml/(s∙g)) and high degree of conversion (up to 100 %). The unreasonableness of the replacement of aluminium nanopowder to coarse-grained powder in this reaction due to the low efficiency is shown in the article. As a solution for pure hydrogen obtaining, a phenomenon of self-heating of aluminum nanoparticles and the resulting hydrogen, as well as the effect of its high-temperature diffusion through the membrane of ultrahigh molecular weight polyethylene were used.

The Influence of Aluminium Nanopowder Density on the Structure and Properties of its Combustion Products in Air

The intermediate and final combustion products of pressed aluminum nanopowder are studied. It is found that the main combustion product is aluminum nitride. In the intermediate stages of combustion, aluminum oxide (γ-Al2O3) and oxynitride (Al5O6N) are the first to form on the sample surface, and aluminum nitride is formed next. The use of sliding (incident at a small angle to the surface) synchrotron radiation made it possible to determine with high accuracy (in time) the sequence of stages of formation of crystalline products during combustion of the aluminum nanopowder.

Raise of nanopowders excess energy by electron beams exposure

It has been found that metal nanopowders produced by wire electrical explosion have stored energy, which is higher than the standard heat of melting. Continuing studies on stored energy the influence of electrons flow (accelerator ELU-4) on iron and nickel nanopowders has been investigated in the paper. It was found that the thermal effect of oxidation for iron nanopowders after exposure increased in comparison to the thermal effect of unirradiated nanopowders 4 times, and for nickel nanopowders 1.4 times. The model of metal nanoparticle with stored energy has been proposed in the article.

Intermediate combustion products of aluminium nanopowder in air

Experimental methods for aluminum nitride rate increase at combustion of aluminium nanopowder in air, such as increase of aluminum nanopowder sample mass, air volume limitation, etc. are examined in the paper. The influence of infrared radiation on aluminium nanopowder and its mixtures samples on aluminum and titanium nitrides rate in combustion products was experimentally investigated in the work. The complex effect of infrared radiation on nitrides rate was established in the paper.

Structural and energetical properties of nanoparticles and nanopowders

It has been found that metal nanopowders produced by wire electrical explosion have stored energy, which is higher than the standard heat of melting. Continuing studies on stored energy the influence of electrons flow (accelerator ELU-4) on iron and nickel nanopowders has been investigated in the paper. It was found that the thermal effect of oxidation for iron nanopowders after exposure increased in comparison to the thermal effect of unirradiated nanopowders 4 times, and for nickel nanopowders 1,4 times. The model of metal nanoparticle with stored energy has been proposed in the article.

Raise of nitrides rate in combustion products of aluminium nanopowder

Experimental methods for aluminum nitride rate increase at combustion of aluminium nanopowder in air, such as increase of aluminum nanopowder sample mass, air volume limitation, etc. are examined in the paper. The influence of infrared radiation on aluminium nanopowder and its mixtures samples on aluminum and titanium nitrides rate in combustion products was experimentally investigated in the work. The complex effect of infrared radiation on nitrides rate was established in the paper.