V. D. Khoruzhii

A plant for studying radiation and thermal desorption of gases from inorganic materials

A high-vacuum plant and methods for studying thermal and radiation-stimulated desorption from solid-state materials are described. Radiation-stimulated desorption was studied using an electron gun with a 1- to 120-keV beam energy, featuring a new technology of power supply units. Partial pressure gages with a sensitivity of up to 10−13 Pa were used to record mass spectra of residual gases. Results of studying thermal- and radiation-stimulated yields of hydrogen from submicrocrystalline samples of a BT-6 alloy are presented to demonstrate the serviceability of the created procedures.

Features of the plasma saturation of nanocrystalline and coarse-crystalline titanium samples with hydrogen and deuterium

We investigate the laws governing the saturation of nano- and coarse-crystalline Ti-6Al-4V alloy samples with hydrogen from high-frequency and glow discharge plasmas with a view to finding materials suitable for making hydrogen accumulators. We conclude that nanocrystalline Ti-6Al-4V alloy holds promise for creating hydrogen accumulators, and hydrogen plasma of high-frequency discharge origin is a cleaner hydrogen saturation medium than that of non-self-sustained discharge origin.

Features of hydrogen accumulation in metals during saturation in plasma, electrolyte, and hydrogen under pressure

Features of the temperature spectra of thermally stimulated gas evolution are investigated to determine features of the incorporation of hydrogen into titanium, palladium, and steel of 12Kh12M1BFR grade (metals substantially different with regard to hydrogen solubility) from media of various aggregate states. The conclusions are drawn with regard to the order of filling of high-temperature and low-temperature traps in dependence on the metal and method of saturation.

Features of the ionization mechanism of radical recombination luminescence excitation

A comparison of the temperature-time cycles of radical recombination luminescence (RRL) in atomic hydrogen, based on ZnS and ZnCdS at different partial pressures, is presented. The obtained results allow us to explain the temperature dependences of chemisorption of the charged form of N+ and the optical transition rate upon RRL.

An installation for the investigation of radiation and thermal gas liberation from inorganic materials

A high-vacuum installation for the qualitative and quantitative investigation of the content of monatomic and molecular gases (hydrogen, oxygen, nitrogen, water vapors, gaseous hydrocarbons, CO2, CO, etc.) on the surface and in the near-surface layers of compact and porous materials is designed. Methods of radiation-stimulated and thermally stimulated desorption, as well as a technological method for degassing solid materials via electron irradiation, are achieved in the installation. The results of an investigation into the hydrogen content upon saturation and its emission from polycrystalline (average grain size d > 1μm) and submicrocrystalline (d < 0.1 μm) titanium under radiation and thermal effects are presented as an example of the use of the abovementioned methods.

Luminescence of solids excited by adsorbed oxygen atoms

The luminescence excited upon the discharge of molecular gases O2, N2O, and CO onto a Zn2SiO4-Mn crystalline phosphor surface prefilled with oxygen atoms is studied. An interpretation of this phenomenon in terms of the model of acceleration of the surface heterogeneous recombination of oxygen atoms in the appearing adsorption layer of oxygen-containing molecules O2, N2O, and CO by the exchange-association mechanism is given.

Dynamics of the luminescence spectra of ZnS-Cu and ZnS-Ag crystalline phosphors in atomic hydrogen

It is shown that the luminescence spectra of the ZnS-Cu and ZnS-Ag crystalline phosphors excited by hydrogen atoms depend on the time of exposure of a sample to hydrogen atoms. The changes in the spectra manifest themselves in the redistribution of the luminescence energy. The nature of these changes and the mechanisms of luminescence excitation by hydrogen atoms are discussed.

Heterogeneous chemiluminescence (GHL) of the ZnSCdS-Cu and phosphors activated by Re ions

Data have been presented of the luminescence of crystalline phosphors, the generation of electron-hole pairs in semiconductors, and simulation of nonequilibrium electron and ion emission from solid surfaces by thermal atoms. The excitation occurs in the process of the energy transfer of several vibrational quanta of the bond, formed on the capture of the atomic particle by the surface, to electrons of the luminescence and emission centers, and to electrons of the valence band, by the surface ions. Relaxation via several vibrational levels is connected with anharmonism of vibrations and is possible in the first order of the bond dipole moment expansion in internuclear coordinates. The population of the upper vibrational levels occurs due to the energy released on capturing the atomic particles by the surface. The vibration electronic and vibration-vibration mechanisms are most effective at the excitation of a solid by light atoms (H, C, O) or, in the presence of such atoms in the newly formed bonds. The probability of the solid excitation per capture act, in this case, can reach tens of percent. The experimental results are presented on the luminescence excitation of phosphors ZnSCdS-Cu and phosphors activated by Re ions in atomic hydrogen.

Temperature-time cycles of radical-recombination luminescence in dependence on the partial pressure of the atoms

A comparison is made of the temperature -time cycles of radical-recombination luminescence in atomic hydrogen of phosphors based on ZnS and ZnSCdS with different partial pressures. The results obtained allow us to plot temperature dependences of the concentration of the charged form of chemisorption N+ and the optical transitions during RRL excited by atomic hydrogen.

The mechanism of radical-recombination luminescence in zinc oxide

The temperature-time relationships of the intensity of radical-recombination luminescence (RRL) and the surface electroconductivity of zinc oxide with excitation by atomic hydrogen have been studied. The results are analyzed on the basis of the electron theory of chemisorption and catalysis and the band theory of crystal-phosphor luminescence. The effect of the state of the gas phase and the deep trapping level on the intensity of the RRL is elucidated. A mechanism is proposed for the RRL excitation of this phosphor.