Methanation of carbon monoxide on nickel and nickel-copper alloys

1976 ◽  
Vol 44 (3) ◽  
pp. 439-448 ◽  
Author(s):  
M ARAKI
Keyword(s):  
Carbon Monoxide ◽  
Copper Alloys ◽  
Nickel Copper

Overlapping energy bands and the theory of collective electron ferromagnetism

1953 ◽  
Vol 49 (1) ◽  
pp. 115-129 ◽  
Author(s):  
A. B. Lidiard
Keyword(s):  
Curie Point ◽  
Energy Band ◽  
Spontaneous Magnetization ◽  
Copper Alloys ◽  
Implicit Assumption ◽  
Energy Bands ◽  
Unknown Parameters ◽  
Nickel Copper ◽  
Predicted Values ◽  
A Minor

ABSTRACTThe theory of collective electron ferromagnetism given by Stoner applies to a system of electrons in a single energy band; for iron, cobalt and nickel this is identified with the band of states derived from atomic 3d functions. To bring in the generally assumed overlapping of the 3d band by the wide 4s band in these metals, the theory has been extended to take account of the transfer of electrons from 3d to 4s states with change of temperature. A previous calculation of this transfer effect must be regarded as inadequate, for the part played by the exchange energy in determining the distribution of electrons between the two sets of states was omitted. The general equations are derived in § 2 and used as a basis for discussion of the properties of nickel-copper alloys at absolute zero in § 3. In §§4 and 5 numerical results are presented which show the effect of the overlapping 4s band on the magnetic properties of a system such as nickel both above and below its Curie point. Comparison with the measured paramagnetic susceptibility of pure nickel above the Curie point strongly suggests that for this metal the overlapping 4s band has only a minor influence, although in principle the effect could be very large (cf. Fig. 4). This result is not unambiguous, however, because values thus inferred for the two unknown parameters lead to inaccurate predictions below the Curie point. First, the predicted values for the spontaneous magnetization are too small. Secondly, the theory demands that the nickel-copper alloys should only be ferromagnetic below a copper content of about 20 %, whereas experimentally the limit is known to be about 60 %. In conclusion, it is suggested that the implicit assumption of Stoner's theory that the exchange integrals between all pairs of 3d states are equal to one another is a more serious restriction on the theory than the consideration of only a single energy band.

The repassivation of nickel-copper alloys in sulphuric acid

1984 ◽  
Vol 24 (4) ◽  
pp. 305-323 ◽  
Author(s):  
R.D.K. Misra ◽  
G.T. Burstein
Keyword(s):  
Sulphuric Acid ◽  
Copper Alloys ◽  
Nickel Copper

scholarly journals Metal reduction by hydrogen from the B2O3-СaO-Ni(Zn, Pb, Cu)O melts thermodynamic modeling

2020 ◽  
Vol 61 (2) ◽  
pp. 145-151
Author(s):  
Alexander S. Vusikhis ◽  
◽  
Evgeny N. Selivanov ◽  
Stanislav N. Tyushnyakov ◽  
Viktor P. Chentsov ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Thermodynamic Modeling ◽  
Reduction Process ◽  
Reducing Agent ◽  
Metal Reduction ◽  
Oxide Melt ◽  
Reduction Processes ◽  
Lead And Zinc ◽  
Nickel Copper ◽  
Copper Lead

Thermodynamic modeling is used to describe the metal reduction processes by hydrogen from oxide melt in the B2O3-CaO- MeO (Me – Ni, Zn, Pb, Cu) system. Open systems approximation with periodic removal of metal particles and gases from the working melt composition is used in the method. By this work we present the thermodynamic modeling results of metal reduction processes (Ni, Cu, Pb, Zn) by Hydrogen. The reducible metals oxides content in the all melts was 3 mass %, and the mass ratio of B2O3/CaO was taken as 3 to be close to eutectic composition. The calculations made it possible to determine such parameters as oxide melt compositions and elements reduction degree depending on the induced gas quantity. of the Nickel, Copper, Lead and Zinc reduction process simulation from B2O3-CaO-MeO melts proved the reduction process by Hydrogen is similar to that which was earlier established when Carbon monoxide was used as the reducing agent. When Copper is reduced from CuO, the process occurs with intermediate Cu2O oxide formation (CuO → Cu2O → Cu). The Nickel (NiO → Ni), Lead (PbO → Pbs + Pbg) and Zinc (ZnO → Zng) recovery have been realized by one stage. The non-ferrous metals change content in the oxide melt and the degrees of its reduction depending on temperature and reducing agent quantity introduced are described by the second-order polynomial functional equations. Comparison of the Carbon monoxide and Hydrogen used for Nickel, Copper, Lead, and Zinc reducing to 90% metallization degree proved much less Hydrogen consumption.

THE BEHAVIOR OF FERROMAGNETICS UNDER STRONG COMPRESSION

1956 ◽  
Vol 34 (3) ◽  
pp. 304-311 ◽  
Author(s):  
F. D. Stacey
Keyword(s):  
Magnetic Fields ◽  
Saturation Magnetization ◽  
Copper Alloys ◽  
Strong Increase ◽  
High Magnetic Fields ◽  
Magnetization Curves ◽  
Nickel Copper ◽  
Strong Compression ◽  
Thin Disks

Specimens in the form of thin disks have been subjected to strong compression simultaneously with high magnetic fields by means of a new design of permeameter, with which their magnetizations have been measured. Magnetization curves extending to saturation have been plotted for a number of materials at (non-hydrostatic) pressures up to 10,000 atmospheres. The most interesting result is the strong increase in saturation magnetization shown by nickel and the nickel–copper alloys.

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