Influence of nanomodication on structure for-mation and properties of structural steel

The state of the problem of grinding the grain structure and improving the mechanical properties of low-alloy structural steels has been studied. The state of the problem of grain structure refinement and improving the mechanical properties of low-alloy structural steels has been studied. The role of nanodispersed additives is reduced to the creation of additional artificial crystallization centers in the melt. They must be consistent with the critical radiuses of the embryos. According to our calculations, for the grinding of primary austenite grains in castings, the size of the introduced particles should be 40–50 nm. Output and modified castings of 09G2 and 09G2S steels were subjected to severe plastic deformation by equal-channel angular pressing followed by low-temperature annealing at 350 °C. In the initial state, cast steels 09G2 and 09G2S had a ferrite-pearlite structure with an average primary austenite grain size of 30 μm; after modification and deformation, the grain size was 10 μm. After quenching and cooling in water, the structure has changed insignificantly - ferritic-reed, with an average grain size of ~ 8...10 microns. After cooling the quenched samples in a solution of 20 % NaCl in water, the structure of packet martensite was obtained. In the initial state, the studied steels have insufficiently high property values: microhardness Нμ up to 3000 MPa, yield point σ 0,2 up to 800 MPa. When quenching in water, the hardness somewhat increases, the most significant increase is observed when the samples are cooled in a NaCl solution. Due to the significant grinding of martensite crystals, accelerated cooling provides a greater increase in hardness. A nanodispersed powder of titanium carbonitride Ti (CN) with a fraction of 50...100 nm was obtained by the method of plasma-chemical synthesis, the process technology was developed. Intensive plastic deformation of 09G2 and 09G2S steel castings was carried out. The structure and properties of steels before and after treatments have been studied. As a result of the combination of hardening methods, the grain size of the steels was reduced by 3 times and the yield strength increased from 3000 to 4000 MPa. Nanodispersed powder of titanium carbonitride Ti (CN) with a fraction of 50...100 nm was obtained by the method of plasma chemical synthesis, and a process technology was developed. Intensive plastic deformation of castings of 09G2 and 09G2S steels was carried out. The structure and properties of steels before and after treatments were studied. As a result of a combination of hardening methods, grinding of steel grains by 3 times and increasing the yield strength from 3000 to 4000 MPa was achieved

Effect of Aluminum Alu C and HCM-40 and Yttrium Oxides Y2O3 on the Properties of Composition Materials Based on Perfluorinated «Neofton N» Rubber

The properties of two groups of composite materials (CM) based on perfluorinated rubber (FFKM) «Neofton-N» with different contents of trivalent metal oxides: pyrogenic aluminum oxide (Alu C), hollow corundum microspheres (HCM-40) and nanodispersed powder yttrium oxide (Y2O3) were obtained and investigated,. The rheometric characteristics of CM cured with 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (BOAP) and perfluorohexamethylene-bis-perfluorohexylimidoylamidine (DPIA-65) and their mechanical properties were determined. Thermogravimetric analysis was used to study their temperature parameters. The possibility of obtaining CM with a high level of properties, operable in the temperature range 250–330 °C, has been shown.

FORMATION OF NANO-AND ULTRAFINE PALLADIUM POWDERS IN THE PRESENCE OF «RED-OX»SYSTEM«TITANIUM (III) - TITANIUM (IV)»

The results of studies on the processes of obtaining ultra - and nanodispersed palladium powders from sulphate solutions by a combined chemical and electrochemical method in the presence of a "red-ox" system of titanium (III) - titanium (IV) are presented. It has been shown that when a titanium trivalent sulphate solution is added to a solution containing palladium (II) ions, palladium ions are immediately reduced to elemental state to form a nanodispersed powder. The completeness of the above-mentioned oxidizing-reducing reactions is established on the basis of calculating the equilibrium constant (K), which is 1034 and indicates that trivalent titanium ions completely reduce palladium ions to elemental state. Effect of initial concentration of palladium ions on amount of formed palladium powder with addition of equivalent amount of trivalent titanium ions is investigated. According to the authors, upon reduction of palladium ions, elemental palladium is formed in the atomic state, and over time, the atoms begin to combine with each other. Subsequently, atomic particles are combined into colloidal particles. It has been found that in the absence of coagulants, the colloidal palladium solution is stable for 2-3 hours, and in the presence of gelatin, the stability increases and remains for 36 hours. It was shown that in all experiments powders with spherical particles are formed, the average sizes of which range from 0.116-0.240 microns. Based on the results of the presented studies, a new technology for producing ultra - and nano-sized palladium powders is proposed.

Copper Oxide of Plasma-Chemical Synthesis for Doping Superconducting Materials

Properties of nanodispersed powder copper oxide, synthesized during arc sputtering of copper in a gas mixture of low pressure oxygen, were studied. It was shown that the particles possess nanometer size and narrow size distribution. The issue of reduction, recrystallization and sintering of nanodispersed powder were discussed.

Radiation-Induced Desorption from the Nanopowder

ABSTRACTThe mechanisms of radiation-induced desorption (RID) from the nanodispersed powder (NDP) surface under the impulse excitation of heavy-current electron beam (HCEB) were studied. Electron-induced desorption (EID); temperature-induced desorption (TID) as a result of radiation heating of the adsorbent; radiation-induced diffusion of the adsorbed atoms; re-adsorption were considered.It was shown that radiation-induced desorption was observed during the first two pulses. The main mechanism of this process was electron-induced desorption (EID).