This article describes how to improve the technology of manufacturing "body pump" parts of EPAN composite material reinforced by nanoscale carbon fibers.
Purpose of research. To study the process of molding and consolidation of preforms from mechanically synthesized powders of europium and cerium hafnates.Methods. Complex compounds of europium hafnateEu2HfO5 and cerium hafnate Ce2HfO5 have been synthesized from europium, hafnate and cerium oxides using mechanochemical synthesis in a planetary centrifugal mill. The rotational speed of the disk was 600 - 900 rpm and the rotational speed of the drums is 1000 - 1800 rpm, with the ratio of grinding bodies to the mass of the powder charge (35 - 45): 1, in an argon atmosphere. Synthesis lasts 5 - 120 minutes.Results. An X-ray phase analysis has been performed showing the formation of Eu2HfO5 and Ce2HfO5; as well as the study of the morphology of particles of the obtained powders, their technological properties, granulometric composition, formability and compaction, as well as the process of their consolidation.Conclusion. On the basis of the experimental studies aimed at studying the molding process and consolidation of preforms from mechanically synthesized powders of europium and cerium hafnates, it has been revealed the optimal mode of synthesis of cerium and europium hafnates. We have obtained a cerium hafnate powder with a particle size of 30-100 nm and a europium hafnate powder with a particle size of 40-70 nm by the method of mechanical activation. Using X-ray phase analysis, TEM and SEM methods, the mixed structure of lanthanide hafnates powders obtained by mechanosynthesis have been studied. The technological properties of mechanically synthesized powders of cerium and europium hafnate, as well as, their compaction and formability after pressing and sintering have been determined and studied. Samples from europium hafnate powder have a relative density higher than samples from cerium hafnate powder after consolidation at temperatures of 900-1200 ° C and isothermal holding time from 30 to 120 min. A study of the microhardness of lanthanide hafnate samples after sintering has shown that europium hafnate samples have greater hardness than cerium hafnate samples .
In the article the study of the effect of temperature electropulse sintering of powder on the properties of steel. The optimal conditions for obtaining medium-carbon steels, cold brittleness threshold is defined, which allows to judge about the possibility of powder steel for use with impact loads at low temperatures.
The purpose of the study is to determine the effect of nanosized additives on the structure and properties of the T15K6 hard alloy.Methods. These studies were carried out using an S-3400N electron microscope. The mechanical and physical properties of the structure of a hard alloy of the WC-TiC-Co system were studied using the example of T15K6 when nanosized tungsten powder and nanosized tungsten carbide powder with cobalt deposited on it were introduced into the initial charge using an optical and electron microscope; An X-ray spectrum analysis of the obtained samples of the T15K6 hard alloy was carried out on a DRON-4 X-ray diffractometer.Results. A hard alloy of the WC-TiC-Co system was studied with the introduction of nanosized tungsten powder into the initial charge, as well as with the introduction of nanosized tungsten carbide with cobalt deposited on its surface.In the work, the used powders of tungsten, nano-tungsten, cobalt, titanium carbide, tungsten carbide, nano-powder of tungsten carbide were studied, and the microstructure of the obtained hard alloys was also studied. It is shown that the coercive force of the T15K6 alloy depends on the size of the cobalt phase regions in the alloy; measuring its value makes it possible to judge the size of carbide grains. To improve the strength properties of hard alloys of the WC-TiCCo system, it is recommended to introduce nanosized WC additives or WC nanopowder with deposited cobalt.Conclusion. To improve the strength properties of hard alloys of the WC-TiC-Co system, it is recommended to introduce nanosized WC additives or WC nanopowder with deposited cobalt. The introduction of these additives into the composition of the powder charge of the T15K6 hard alloy leads to an increase in the ultimate bending strength by 15%. The introduction of nanosized WC additives or WC nanopowder with deposited cobalt makes it possible to obtain a fine-grained structure with a grain size of no more than 4–6 μm.
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