Journal of Surface Science and Technology

E. A. Baklachev ¹, N. M. Beylerian ¹, H. A. Ghasarian ¹

Affiliations
1 Depurtmenr of Physical and Colloid Chemistry, Yerevan Stute University, Yerevan-375049, Munoogian st. 1, IN

Abstract

Dispersed oxides, e.g. silica, when treated with penetrating radiation in the region of small doses (50-150 Gy) show maxima in physical properties (specific density, surface concentration of hydroxyl groups, adsorption ability) with raditation doses. The radiation yields (Y) of the determined physical parameters are of the order 10⁴ per 100 ev. A reorganization of the surface hydrate-hydroxylic via glass state-quartz-glass state path has been considered to occur.

Keywords

Radiation Modification, Surface Properties, Silica Modification.

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N. M. Beylerian ¹, E. A. Baklachev ¹, H. A. Ghazarian ¹

Affiliations
1 Department of Physical and Colloid Chemistry, Yerevan State University, Yerevan-375049, A. Manoogian St. 1, AM

Abstract

The modification of TiO₂, surface properties under the action of small doses (D ≃ 10₂ Gy) of γ-radiation has been studied. It has been established that the used doses are enough to stimulate polymorphic changes in the surface layers of dispersed TiO₂. In spite of the fact that the radiation energy is being absorbed by the volume of the subject, surface structure reconstruction occurs only in the narrow presuperficial layers. The changes of the properties studied (for example, the adsorption ability, crystal density, surface hydroxylic cover concentration, the ratio of acid/base centers) are due to the change of the crystal structure of the initial oxide on γ-iradiation in the region of small doses.

Keywords

Titanium Oxide, Radiation Modification, Surface Properties, Hydrated Layer Reconstruction, Action of Small Doses.

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E. A. Baklachev ¹, N. M. Beylerian ¹, H. A. Ghazarian ¹

Affiliations
1 Department of Physical and Colloid Chemistry of the Yerevan State University, Yerevan-375049, Manoogian st. 1, AM

Abstract

Some surface reactions which occur between modified under the action of small doses (D) of penetrating radiation on aerosil with polyamide and epoxy resins have been studied. Experimental data on the basis of the reconstruction of surface hydratehydroxylic cover have been discussed. It has been shown that adhesive properties of glues prepared using aerosil-type modified fillers depend on the conditions of preliminary treating of blends. The diffractographic analysis of unmodified and modified with γ-radiation (D = 100 Gy) silicon samples shows that under the action of radiation, phase transition occurs on SiO₂ crystoballite and tridimite phases are formed.

Keywords

Aerosil, Radiation Modification, Filled Composites, Phase Transition.

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E. A. Baklachev ¹, N. M. Beylerian ¹

Affiliations
1 Department of Physical and Colloid Chemistry of the Yerevan State University, Yerevan-375049, Manoogian st. 1, AM

Abstract

The modification of ZnO surface properties using γ-radiation of small doses (D ∼ 10²Gy) has been studied. The adsorption of stearic acid, triethylamine, phenylglycidylether, polyamide and polyepoxide type resins, the adsorption and desorption of water molecules on modified ZnO have been investigated.

The increase of their adsorption has been discussed assuming that under the action of small doses of radiation a reconstruction of hydrated-hydroxylated cover on ZnO surface occurs.

The important role of crystalline side-specificity has been shown. The radiation changes the microstructure of each side, e.g. (0001), (0001) (1010).

Keywords

Zinc Oxide, Radiation Modification, Surface Properties, Dehydration and Dehydroxylation of Surface Layers, Crystalline Side-Specificity.

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E. A. Baklachev ¹, N. M. Beylerian ¹, H. A. Ghazarian ¹

Affiliations
1 Department of Physical and Colloid Chemistry, Yerevan State University, Yerevan-375049, A. Manoogian St. 1, AM

Abstract

The adsorption ability, specific surface area, density changes and also the dehydration regularities of two kinds of MgO, obtained from Mg(OH)₂, under different conditions and irradiated with small doses (D) of γ-radiation, have been studied. Combining these results with the data concerning the thermo- and X-ray phase analysis, crystalochemical transformations occurring on MgO surface layers have been established. The dependence of the studied properties on D shows that in the regions D ≤ 100 - 150 Gy and D ≥ 150 Gy, different transformations occur which pre-determines the external character of property versus dose dependence. The observed changes are due to the reconstruction of surface layers by the route : brucite → periclase → brucite.

Keywords

Magnesium Oxide, Radiation Modification, Surface Properties, Small Doses Action.

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E. A. Baklachev ¹, N. M. Beylerian ¹, H. A. Ghazarian ¹

Affiliations
1 Yerevan State University, Yerevan-375049, AM

Abstract

The influence of irradiation in air in the region of small doses on the surface properties of alumina has been studied. Three types of alumina have been used, each of which differs from the others in density, specific surface and content of α-phase in them. On the basis of experimental data concerning the adsorption and desorption of triethylamine, stearic acid and water, X-ray phase analysis, surface acid-base centres and density changes, it has been concluded that an appreciable reconstruction of surface structure with unusually great yields, occurs at room temperatures.

Keywords

Alumina, Surface Properties, Radiation Modification.

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