English English

Keywords: nanoparticles

Plasma electrolyte production of titanium oxide powder

https://doi.org/10.58224/2618-7183-2022-5-6-75-84
, , ,
 75-84 p.
Abstract
The work is devoted to the research of plasma-electrolyte process realized in conditions of cathodic polarity of active metal electrode and its immersion into electrolyte to produce titanium oxide micro- and nanoparticles as well as titanium oxide-coated particles up to 10 μm in size. Two modes of discharge combustion differing in heat generation and concentration of electrolyte solution on particle size distribution were found to influence. Voltage increase can result in discharge combustion in arc mode due to thermal emission of electrons and intensive heating of titanium cathode. This, in its turn, leads to formation of titanium particles up to 10 μm in size, which surface is oxidized. It was found that discharge combustion in the regime with less heat emission leads to formation of titanium oxide particles sized less than 1 µm. These powders can be used in additive manufacturing, powder metal-lurgy and as additives in composite materials.
PDF

Structure and analysis of amorphous silicon dioxide nanoparticles

https://doi.org/10.58224/2618-7183-2022-5-6-85-94
, , , , , ,
 85-94 p.
Abstract
One of the most common methods of studying as well as controlling the environment and production products is the method of chromatography. The main working element that separates components into components, in particular, is silicon dioxide powder of nano and micro sizes. At the same time powder materials are widely used and relevant for powder technologies of additive construction. The aim of the work is to study the structure and analysis of obtained nanoparticles of amorphous silicon dioxide, satisfying the characteristics for use in high-performance liquid chromatography columns, as well as in various additive technologies. Studies have shown that the method of introducing water vapor in the plasma chemical reactor of the installation for the production of amorphous silica significantly affects the presence of free hydroxyl groups. In the infrared spectrum of the product, which was caught at a distance of 2 meters the line 3750 cm-1 is absent. At a distance of 1 meter the intensity of the line as a reference with 100% value. When a small amount of NaCl was added to the briquette used in spraying, the intensity dropped by 50%. When removed 1.5 meters away, the intensity is 75%. It follows that in the hotter gas during rapid cooling more OH hydroxyl groups are formed on the surface of the aggregates, when moving away from the reactor i.e. cooling the outgoing gas OH groups are formed less.
PDF

Study of the plasma-electrolyte process for producing titanium oxide nanoparticles

https://doi.org/10.58224/2618-7183-2022-5-5-70-79
, , , ,
 70-79 p.
Abstract
The work is devoted to the investigation of the process of obtaining titanium oxide nanoparticles by burning high voltage DC gas discharge in an argon atmosphere when an aqueous solution is used as one of the electrodes. It was found that using an aqueous glycine solution in an inert gas medium, the plasma-electrolyte process using a streamer discharge is well suited for producing titanium oxide nanoparticles. An important regularity of particle size decrease with the increase of argon pressure in the chamber was revealed. Thus, when the pressure is increased from 1 MPa to 3 MPa, a sharp decrease in the average particle size from 62 nm to 16 nm is observed, while the changes in the aver-age particle size are not cardinal already in the process of pressure increase up to 5 MPa. A narrowing of the dispersion composition scatter with increasing pressure for 1 MPa - ± 40 nm, 3 MPa - ± 20 nm and 5 MPa - ± 8 nm was determined. The presence of titanium oxide particles was confirmed on the basis of plasmon resonance detection at 224, 230 and 235 nm.
PDF

Development of a plasma-chemical method for producing amorphous silicon dioxide nanoparticles

https://doi.org/10.58224/2618-7183-2022-5-5-80-90
, , , , , ,
 80-90 p.
Abstract
One of the most promising areas of production is additive technologies of building, in particular powder 3D printing. The aim of the work is to create a plasma-chemical method of obtaining amorphous silicon dioxide, satisfying the characteristics for the use of additive technologies of build-ing products, as well as in columns used in high performance liquid chromatography - one of the most common methods of study, as well as control of the environment and production products. One of the main requirements for particles is a porous structure with a surface that has a chemically bonded or physically coated active phase used for separation. Experimental installation for obtaining amorphous silica was developed, the feature of which was the possibility of rapid and continuous supply of pressed briquettes, rather than powdered material as it was previously. Studies have shown that the developed plasma-chemical process implemented in the condition of evaporation of briquettes consist-ing of 70% sand and 30% coke is effective enough to produce silicon oxide nanoparticles smaller than 200 nm. The developed method of obtaining nanoparticles should be further investigated on the ability to obtain nanoparticles smaller than 20 nm, it is so necessary to obtain the specific surface area of 200 m2/g, which will make it possible to produce from this raw material particles of the fixed phase carrier column of high-performance liquid chromatography.
PDF

STUDY OF ARTIFICIAL CERAMIC BINDERS BASED ON SILICATE MATERIALS FOR CERAMICS INDUSTRY

https://doi.org/10.34031/2618-7183-2018-1-3-11-16
, ,
 11-16 p.
Abstract
This article discusses the possibility of using artificial ceramic binders obtained by the technology of highly concentrated binder suspensions in the production of ceramic materials and products. The results of complex studies of suspensions of artificial ceramic binders based on feldspar and quartz sand, as well as the results of tests of the samples obtained on their basis are presented. A definite advantage of entering the suspensions in the molding compositions of the slurries used in the manufacture of certain varieties of pottery is proved. The solution of the problem of import substitution of raw materials components, caused mainly by the difficult political situation in the country, as well as the lack of its own raw material base of good quality, in connection with which the paper proposes the use of technology of highly concentrated binder suspensions, which allows to optimize the quality of domestic raw materials. The use of technology of highly concentrated binder suspensions, allows not only to expand the assortment and range of products produced by this technology, but also to improve the quality and economic feasibility of individual varieties of ceramics. The emphasis on the introduction of technology of highly concentrated binding suspensions in certain areas of ceramics production is explained by the formation of a completely different structure of materials due to the increased content of nanoparticles in the composition of artificial ceramic binding suspensions, which contributes to a significant increase in mechanical strength while optimizing other basic technological quality indicators for ceramic materials and products. The possibility of reducing the firing temperature by 50-100°C, however, this issue requires additional research.
PDF