scholarly journals Chemical reactions during sintering of Fe-Cr-Mn-Si-Ni-Mo-C-steels with special reference to processing in semi-closed containers

2015 ◽  
Vol 47 (1) ◽  
pp. 61-69 ◽  
Author(s):  
A. Cias
Keyword(s):  
Mechanical Properties ◽  
Carbon Monoxide ◽  
Special Reference ◽  
Water Vapour ◽  
Chemical Reactions ◽  
Thermodynamic Data ◽  
Alloying Elements ◽  
Bearing Steels ◽  
Kinetics Of

Sintering of Cr, Mn and Si bearing steels has recently attracted both experimental and theoretical attention and processing in semiclosed containers has been reproposed. This paper brings together relevant thermodynamic data and considers the kinetics of some relevant chemical reactions. These involve iron and carbon, water vapour, carbon monoxide and dioxide, hydrogen and nitrogen of the sintering atmospheres and the alloying elements Cr, Mn, Mo and Si. The paper concludes by presenting mechanical properties data for three steels sintered in local microatmosphere with nitrogen, hydrogen, nitrogen-5% hydrogen and air as the furnace gas.

scholarly journals METHOD FOR DETERMINING QUASI INVARIANTS IN KINETICS OF CHEMICAL REACTIONS

2018 ◽  
Vol 59 (5) ◽  
pp. 72 ◽  
Author(s):  
Vladislav Kh. Fedotov ◽  
Nikolaiy I. Koltsov
Keyword(s):  
Carbon Monoxide ◽  
Chemical Reactions ◽  
Oxidation Reaction ◽  
Equilibrium Constants ◽  
Kinetic Relations ◽  
Kinetics Of

A method was developed for determining the approximate kinetic relations (quasi-invariants), which connect equilibrium constants of multi- step reactions with reagent concentrations measured in several non-stationary experiments (multi-experiments). With this method use the quasi-invariants were defined for the oxidation reaction of carbon monoxide proceeding through different mechanisms.

Analysis of the kinetics of sublimation of alloying elements in alloys with allowance for chemical reactions

1986 ◽  
Vol 21 (6) ◽  
pp. 566-570
Author(s):  
V. S. Pavlina ◽  
V. N. Fedirko ◽  
Ya. S. Matychak ◽  
T. S. Tarlupa
Keyword(s):  
Chemical Reactions ◽  
Alloying Elements ◽  
Kinetics Of

scholarly journals Interaction of steam and charcoal at low pressures

1947 ◽  
Vol 189 (1016) ◽  
pp. 1-10 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Water Vapour ◽  
Adsorption Data ◽  
Initial Adsorption ◽  
Low Pressures ◽  
Kinetics Of

The reaction between charcoal and water vapour at temperatures up to 700° C and at pressures of less than 1 mm. has been studied. Water vapour, hydrogen and carbon monoxide have all been shown to be reversibly adsorbed at the reaction temperatures. Hydrogen is adsorbed strongly and rapidly; carbon monoxide is adsorbed in considerably smaller quantity and much more slowly. When charcoal reacts with water vapour at low pressures, the pressure falls during the rapid initial adsorption of the water vapour, and subsequently rises during the desorption of the product gases. The proportions of carbon monoxide and hydrogen in the product gases were found to vary throughout the reaction in a special manner. The variations can, however, be simply explained on the basis of the adsorption data. The kinetics of the reaction at higher pressures are discussed: they can likewise be adequately explained on the basis of the adsorption data. Reasons are given for supposing that the water vapour is adsorbed in the molecular condition.

Study of nickel-molybdenum catalysts for methanation of carbon monoxide

1980 ◽  
Vol 45 (3) ◽  
pp. 783-790 ◽  
Author(s):  
Petr Taras ◽  
Milan Pospíšil
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Mixed Oxides ◽  
Minor Component ◽  
Fast Neutrons ◽  
Scanning Calorimetry ◽  
Low Concentrations ◽  
Γ Rays ◽  
Molybdenum Catalysts ◽  
Kinetics Of

Catalytic activity of nickel-molybdenum catalysts for methanation of carbon monoxide and hydrogen was studied by means of differential scanning calorimetry. The activity of NiMoOx systems exceeds that of carrier-free nickel if x < 2, and is conditioned by the oxidation degree of molybdenum, changing in dependence on the composition in the region Mo-MoO2. The activity of the catalysts is adversely affected by irradiation by fast neutrons, dose 28.1 Gy, or by γ rays using doses in the region 0.8-52 kGy. The system is most susceptible to irradiation in the region of low concentrations of the minor component (about 1 mol.%). The dependence of changes in catalytic activity of γ-irradiated samples on the dose exhibits a maximum in the range of 2-5 kGy. The changes in catalytic activity are stimulated by the change of reactivity of the starting mixed oxides, leading to different kinetics of their reduction and modification of their adsorption properties. The irradiation of the catalysts results in lowered concentration of the active centres for the methanation reaction.

New highly efficient coulometric cell with homogenous potential distribution on the working electrode

1986 ◽  
Vol 51 (3) ◽  
pp. 636-642
Author(s):  
Michal Németh ◽  
Ján Mocák
Keyword(s):  
Chemical Reactions ◽  
Potential Distribution ◽  
Anaerobic Conditions ◽  
Highly Efficient ◽  
Working Electrode ◽  
Constant Potential ◽  
Quantitative Analyses ◽  
Mechanism And Kinetics ◽  
Kinetics Of

A highly efficient coulometric cell was designed and constructed, ensuring a constant potential over the whole surface of the working electrode and suitable for very rapid electrolysis. It consists of concentric cylindrical Teflon parts; also the working and auxiliary electrodes are cylindrical and concentric. Electrolysis can be carried out under anaerobic conditions. Functioning of the cell was tested on the oxidation of hexacyanoferrate(II) and chlorpromazine and reduction of hexacyanoferrate(III). The new cell is suitable for routine quantitative analyses and in studying the mechanism and kinetics of moderately rapid chemical reactions.

Kinetics of catalytic conversion of methanol at higher pressures

1980 ◽  
Vol 45 (12) ◽  
pp. 3402-3407 ◽  
Author(s):  
Jaroslav Bartoň ◽  
Vladimír Pour
Keyword(s):  
Low Temperature ◽  
Reaction Kinetics ◽  
Water Vapour ◽  
Kinetic Data ◽  
Catalytic Conversion ◽  
The Given ◽  
Kinetics Of

The course of the conversion of methanol with water vapour was followed on a low-temperature Cu-Zn-Cr-Al catalyst at pressures of 0.2 and 0.6 MPa. The kinetic data were evaluated together with those obtained at 0.1 MPa and the following equation for the reaction kinetics at the given conditions was derived: r = [p(CH3OH)p(H2O)]0.5[p(H2)]-1.3.

Kinetics of catalytic reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst

1983 ◽  
Vol 48 (11) ◽  
pp. 3202-3208 ◽  
Author(s):  
Zdeněk Musil ◽  
Vladimír Pour
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxide ◽  
Rate Equation ◽  
Catalytic Reduction ◽  
Zero Order ◽  
Spectroscopic Measurements ◽  
First Order ◽  
Ir Spectroscopic ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst (8.36 mass % CuO) were determined at temperatures between 413 and 473 K. The reaction was found to be first order in NO and zero order in CO. The observed kinetics are consistent with a rate equation derived from a mechanism proposed on the basis of IR spectroscopic measurements.

Sign in / Sign up

Export Citation Format

Share Document