LATE INTRA-MOULD GRAPHITIZING MODIFYING IS EFFECTIVE WAY OF PREVENTION OF CHILLING EFFECT IN IRON CASTING

The efficiency of the method of late intra-form graphitizing modifying of composition of modifiers Superseed 75, SB5 and фс65р3М1 as compared to ladle modification for disposal of such foundry defect as corner chill is shown

Influences of Co-Content on the Physico-Chemical and Catalytic Properties of Perovskite GdCo_xFe_1−xO₃ in CO Hydrogenation

The effect of the substitution of cobalt into the GdFeO3 perovskite structure on the selective hydrogenation of CO was investigated. A series of GdCoxFe1−xO3 (x = 0; 0.2; 0.5; 0.8; 1) samples were synthesized by sol-gel technology and characterized by XRD, BET specific area, DSC, TG, EDX and XPS. The experimental data made it possible to reveal a correlation between the state of iron and cobalt atoms, the fractions of surface and lattice oxygen, and catalytic characteristics. It has been found that varying the composition of GdCoxFe1−xO3 complex oxides leads to a change in the oxygen-metal binding energy in Gd-O-Me, the ratio of metals in various oxidation states, and the amount of surface and lattice oxygen, which affects the adsorption and catalytic characteristics of complex oxides

THE MODERN APPROACH TO THE QUALITY INCREASE OF CASTING BLOCKS AND HIGH-PERFORMANCE COMPOUNDS FOR PROCESSING OF MELTS ON THE BASIS OF ALUMINUIM

In the article there is given the group of measures, aimed at increase of quality of cast ingots and of high-performance compounds for processing of melts on the basis of aluminium

Features of the Catalytic Cracking of Propane with a Step-Wise Change Pr_xYb_2−xZr₂O₇

In this paper, the features of catalytic cracking of propane with a step-wise change in the composition of the catalyst from Pr2Zr2O7 to Yb2Zr2O7 were considered. For the research, samples of catalysts Pr2Zr2O7, (Pr0.75Yb0.25)2Zr2O7, (Pr0.5Yb0.5)2Zr2O7, (Pr0.25Yb0.75)2Zr2O7 and Yb2Zr2O7 were synthesized and analyzed. Analysis of the results from catalytic experiments showed that for the catalyst (Pr0.25Yb0.75)2Zr2O7, at a temperature of 700 °C, the conversion of propane reaches values of 100%, but for Yb2Zr2O7, this indicator decreases to 84%. The selectivity for ethylene is consistently reduced from 85% to 28% in several catalysts (Pr0.75Yb0.25)2Zr2O7 > Pr2Zr2O7 > (Pr0.5Yb0.5)2Zr2O7 >(Pr0.25Yb0.75)2Zr2O7 > Yb2Zr2O7. An increase in the number of surface adsorption centers leads to a predominant rupture of the C–C bond in the propane molecule with the formation of ethylene. When ytterbium ions are introduced into the catalyst, the amount of ethylene in the reaction products decreases, but the selectivity for propylene increases in the series Pr2Zr2O7 0.75Yb0.25)2Zr2O7 0.5Yb0.5)2Zr2O7 2Zr2O7 0.25Yb0.75)2Zr2O7, which is associated with a decrease in the binding energy of carbon atoms in propane with the catalytic center during adsorption

ON MECHANISM OF FORMING OF STRUCTURAL CONSTITUENTS AT CRYSTALLIZATION OF MODIFIED EUTECTIC IN SILUMINS .

The mechanism of silumins structure formation on the basis of data of thermal, metallographic, microentgenospectral analysis is discussed.The theoretical conclusion is that crucial role in structure formation of eutectic belongs to Si-phase

EFFECTIVE WAYS OF THE REFINING-MODIFYING PROCESSING OF HYPEREUTECTIC SILUMINS

New effective preparation for modifying of hypereutectic silumins AK18 — piston alloy is created on the basis of research-experimental-industrial works

SOME PECULIARITIES OF TECHNOLOGY AND ORGANIZATION OF ALUMINIUM AND ITS ALLOYS RECYCLING

Some peculiarities of technology and organization of recycling of aluminium and its alloys are examined. Analysis of peculiarities of the melting technology in rotor furnace and organization of aluminium and its alloys recycling shows that modern production provides high efficiency of the process, ensuring high quality of alloys

Insights into the Reactivity of Gd_2−xSr_xFe₂O₇ (x = 0 ÷ 0.4) in CO Radical Hydrogenation

The effect of strontium substitution in the structure of the complex oxide Gd2SrFe2O7 on the production of light olefins by CO hydrogenation was investigated. Perovskite-type oxides Gd2−xSr1+xFe2O7 (x = 0; 0.1; 0.2; 0.3; 0.4) were synthesized by sol–gel technology and characterized by XRD, Mössbauer spectroscopy, BET specific area, acidity testing, and SEM. The experimental data revealed a correlation between the state of iron atoms, acidity, and catalytic performance. It was found that with an increase in the content of Sr2+ in the perovskite phase, the basicity of the surface and the oxygen diffusion rate increased. This contributed to the CO dissociative adsorption, formation of active carbon, and its further interaction with atomic hydrogen