International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Compositions of mechanoactivated silicatecontaining particles used as modifiers of polymer matrices have been developed. The morphology, particle sizes of the modifier, the nature of their distribution in the polymer matrix, as well as the topography of the friction surface of samples from modified polymers were studied using scanning electron and optical microscopy. Introduction of mechanically activated particles in concentrations from 0.01 to 2 wt. % into the polymer matrix of a reactoplastic polymer based on epoxy resin leads to multilevel modification, expressed in a change in the morphology of the test sample at the supramolecular, intermolecular and molecular levels. The effect of additives of nanophase modifiers on the wear rate of the developed nanocomposite materials is investigated. The introduction of composite mechanically activated nanodispersed particles into a reactive polymer based on epoxy resin leads to a decrease in the coefficient of friction in the studied range of modifier concentrations, loads and test speeds. Studies of the morphology of the surface of the analyzed samples have shown the presence of a separation layer on the surface of rubbing bodies, contributing to a significant decrease in the coefficient of friction. In the structure of this coating, the presence of nanophases is observed, which have a positive effect on the wear resistance of the developed composite material.

The article presents the results of studies on the study of the physical and mechanical characteristics of polymeric materials modified with mechanically activated particles. It is shown that the use of mechanically activated nanosized particles makes it possible to achieve a significant effect of increasing operational characteristics at relatively low degrees of modification of 0.05% wt. – 3% wt. The use of modifiers at such concentrations in polymer matrices makes it possible to preserve the basic technology for the processing of polymeric materials and equipment in the manufacture of composite materials on a polymer matrix.

In the present paper authors investigated the effect of 2 wt % SiO₂ addition on the initial sintering stage of tetragonal zirconia nanopowder 3Y-TZP (ZrO₂-3 mol% Y₂O₃) which was manufactured by co-precipitation and mechanical mixing methods. It has been found that small amount SiO₂ has influenced on phase composition, crystallite size and agglomeration degree of zirconia nanopowders. The sintering behavior of 3Y-TZP with and without addition SiO₂ was investigated using the dilatometric data and analytical method for determining the sintering mechanism. The shrinkage behavior of all nanopowders was measured under constant rate of heating (CRH). The sintering mechanism on the initial sintering stage of 3Y-TZP changed from (VD) volume to (GBD) grain boundary diffusion by addition 2 wt% SiO₂ (3Y-TZP+2 wt% SiO₂) which have manufactured by co-precipitation method. The nanopowder 4PMM-3Y-TZP+2 wt% SiO₂ which has manufactured by mechanical mixing methods sintered according to (VD) volume diffusion mechanism.

At the contemporary conditions of cast production there has been a permanent interest in economically more profitable technologies for obtaining moulds and cores of controlled properties. A part of this interest is related to quartz sands as a basic and the most common component in the practice of foundry mixture productions. State of sand surface and its influence in formation of foundry mould and core physico-chemical properties are of particular importance.
In this report, various conditions of mechanical activation on the surface of quartz sand in “a fluidized bed” are discussed. The theory of such activation necessity has been partly explained. The “time” factor in preserving the activated layer potential is noticed. The efficiency of the activated layer in producing foundry mixtures strength by the method “No Bake is shown.

The results of the development of a process for the production of powder porous materials (PPM) based on a granular mechanically activated aluminum oxide powder have been presented. The dynamics of the particle size change of alumina powder depending on the time of mechanical activation by means of a high-energy mill of planetary type has been studied. The development results of permeable materials based on granular mechanically activated oxide ceramic powder have been presented. The developed PPMs are applied for liquid and gas filtration, production of calibration elements for control and measuring devices and equipment.

In the present study authors examined the sintering behavior on the initial sintering stage of fine tetragonal zirconia nanopowders (containing 3 mol % Y2O3) with and without mechanical activation in a ball mill. The initial sintering behavior was examined by constant rate of heating method (CRH) at different heating rates. We defined a role of the particles surface mechanical activation and its influence on the sintering mechanisms during the sintering of yttrium-stabilized zirconia nanopowders. We found that even a small mechanical action causes change initial characteristics of nanopowdres which can accelerate sintering processes. Increases of milling time causes change of sintering mechanism from volume (VD) to the grain-boundary (GBD).