Toshisada Mori

Free energy of formation of MoO2 at steelmaking temperature from EMF measurement

The standard free energies of formation of MoO2 and CoO were determined by means of solid oxide galvanic cell; The free energy of formation of MoO2 at steelmaking temperature calculated fromthe data of cell(I), cell(II) and the free energy of formation of NiO is quite consistent with that calculated from the emf of cell(III). An experimental difficulty for the case of the CoCoO electrode above 1673K is discussed. One check on the applicability of the MoMoO2 electrode as an oxygen sensor is included.

Oxygen permeability of calcia-stabilized zirconia

Oxygen permeability of commercial calcia-stabilized zirconia has been measured at 1673 to 1823 K by the following cell; O2 ZrO2(CaO) N2 - O2 (P’tO2 = 1 atm) solid electrolyte (P″O2 = 0.39 - 1010-3 atm). Oxygen permeability of calcia-stabilized zirconia is proportional to (1 - P″O21/4). From the permeability measurement, the conduction properties of the electrolyte were log σ-‡b+ = 0.28- 5100/T and logPb+ =-0.87 + 15,400/T where σ-‡b+ is the þ-@#@ type electronic conductivity at PO2 = 1 atm, and Pb+ is the oxygen activity at which the þ-@#@ type electronic conductivity and the ionic conductivity are equal.

Electronically driven transport of oxygen from liquid iron to CO + CO2 gas mixtures through stabilized zirconia

Transport of oxygen in the following electrochemical system was investigated;O (liquid iron) Oin2− (in ZrO22−CaO) O2 (CO + CO2)An alumina crucible was charged with liquid iron containing 580 ± 10 ppm oxygen. A calcia-stabilized zirconia tube (closed at one end) was immersed in the liquid iron. The inside of the zirconia tube was flushed with a stream of CO + CO2 gas mixture. Oxygen was removed from liquid iron to the CO + COO2 gas mixture without application of an external current. Kinetics of oxygen transport in this system are discussed in terms of mixed ionic and electronic conduction of the zirconia, and also diffusion of oxygen in liquid iron. The rate controlling step for this oxygen removal process was found to be transport of oxygen across a boundary layer in the melt at the melt/electrolyte interface.

Electrochemical measurement of oxygen in liquid nickel

Abstract E.m.f. measurements on the galvanic cell: Mo|Mo + MoO 2 |ZrO 2 (CaO)|O(in Ni)LaCrO 3 |Pt were performed at 1773, 1823, and 1873 K to determine the thermodynamic properties of oxygen dissolved in liquid nickel. The Gibbs energy change for the solution of oxygen in liquid nickel was determined as ΔG° (O)/kJ mol −1 = −RT In [a (O) /p {O 2 (Ni)} 1 2 ] = −{81.8 + 0.0084( T K )} ± 1.2 where p{O2(Ni)} is the oxygen partial pressure in equilibrium with oxygen dissolved in liquid nickel, and the Henrian activity a(O) of oxygen is referred to the dissolved oxygen in hypothetical (Ni + 1 mass per cent O) solution.

Oxygen Permeability of Calcia-Stabilized Zirconia at Low Oxygen Partial Pressures

AbstractThe oxygen permeability of commercial ZrO2 +5.8 to 5.9 wt pct CaO has been measured between 1673 and 1823 K by the following cell: The oxygen permeability of calcia-stabilized zirconia is proportional to . From the permeability measurements, the conduction properties of the electrolyte were obtained.

Thermodynamic study of liquid PbO + GeO2 slags by means of solid-oxide galvanic cell

Abstract The thermodynamic properties of liquid PbO + GeO 2 slags have been measured by means of the solid-oxide galvanic cell: Ni(S)|NiO(s)|ZrO 2 (CaO)|(GeO 2 )(1)|Pb(1) The activities of PbO were obtained with an accuracy of ±3.7 per cent. The Gibbs energies, enthalpies, and entropies of mixing were obtained as functions of slag composition. The polymerization theory of Masson was applied to the system, and it was found that the ionic distribution in lead germanate was quite similar to that in lead silicate. The standard Gibbs energies of formation of the complex compounds 4PbO·GeO 2 , 3PbO·2GeO 2 , and PbO·GeO 2 were calculated.

Electrochemical measurements of oxygen in liquid iron + nickel alloys at 1873 K

An electrochemical method involving solid electrolyte has been applied to the determination of thermodynamic properties of oxygen dissolved in liquid iron + nickel alloys at 1873 K. The electrochemical cell is Mo|Mo + MoO2|ZrO2(CaO)|O(in Fe + Ni)|Mo . The activity of oxygen determined from the e.m.f. of the cell showed a fairly good agreement with the results in earlier literature by means of H2H2O equilibrium method, but showed a fairly large discrepancy with the results by means of COCO2 gas equilibrium method for high nickel alloys.

A Stduy on the Heat Treatment of Cr-Mo Steel (Second Report)

Rectangular specimens and chain link plate specimens were taken from a cold rolled Cr-Mo steel plate. Various factors that affect the elongation of these specimens were investigated. These factors are as follows:1) Quenching temperature, 2) Holding time at quenching temperature, 3) Tempering temperature, 4) Coloring temperature and time.The elongation of specimen was measured by means of a jig boring machine having the precision of 10-3mm. The obtained results are summarized as follows:(1) Quenched rectangular specimen without annealing pretreatment scarcely shows any bending.(2) Quenching temperature and the holding time have the greatest effect on the change of elongation of the rectangular specimen.(3) The effect of tempering and coloring treatment on the elongation of the rectangular specimen is quite similar to that in the case of the annealed specimen, which was shown in the previous report.(4) The average value of the contraction of the rectangular specimen given by the whole tratment is 2.8×10-3mm/cm.(5) Quenching temperature has the greatest effect on the change of the elongation of the chain like plate specimen.(6) Tempering temperature is more sensitive to the elongation in this case than in the case of the rectangular specimen, and, therefore, the variation of tempering temperature must be kept as small as possible.(7) The change of the condition of coloring treatment does not show any significant effect on the elongation of the specimen.(8) Chain link plate specimen is deformed irregularly by the whole treatment.(9) The average value of the contraction of chain like plate specimen given by the whole treatment is 2×10-3mm/cm in the direction of the longest axis.

On the Schnadt Impact Test of Higth Strengh Low Alloy Steels by

Four kinds of Si-Mn high strength low alloy steels were hot rolled into plates of 12 and 22 m/m in thickness. Schnadt impact test was carried out in the range of temperature from -80 to 97°C to investigate the effect of the degree of reduction in plate thickness, gas cutting, shearing, welding, and chemical composition on the transition temperatures and impact properties of these plates.The results obtained are as follows;1) Schnadt impact properties of the specimens taken from the thin plates are generally superior to those of the specimens taken from the thick plates.2) Gas cutting seems to reduce the notch sensibility of the plates which is rather advantageous, while the sheared surface has the trend to be notch sensible. Weld metal used is excellent in toughness.3) Suitable contents of aluminum and nitrogen in the form of aluminum-nitride seem to have a good effect on the impact properties of steel plates. Attention should be paid, therfore, in the deoxidation of molten steel to leave a small content of metallic aluminum in the steel.4) The temperature of complete brittleness (i.e. Bifractance defined by Schandt) of the specimens is lower than -15°C when the Venant number is assumed to be 20, while that of full plasticity (Octafractance) lies in a relatively high temperature range. This tendency is more conspicuous in the thick plates.5) Transition temperature is lowered as the number of Venant is increased. Transition temperature of the thin plates is lower than that of the thick plates.6) These results show that the test plates belong to high or moderate class of high strength low alloy steels when compared with the various foreign types of steels of the same kind.