The Wicke-Kallenbach method had not been applied to the high temperature measurement due to the difficulty in preventing gas leakage from the portion between the diffusion cell and a sample. However, this problem has been overcome by the development of an Na₂O-SiO₂ cement containing liquid phase at elevated temperatures.
This technique made it possible to evaluate the effective dif fusivities of Ar-He through coke and graphite over a wide temperature range of 20 to 1300°C. The effective difusivities for CO-CO₂ up to 300°C and permeation fluxes for argon and helium up to 1000°C were also measured. From the measurements, molecular, Knudsen and surface diffusion through pores could be evaluate independently.
The technique proposed in the present work has also been applied to the in situ measurement of the effective diffusivity of Ar-He through coke in the course of oxidation with carbon dioxide.

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The lower limit of energy consumption in the actual iron ore sintering process was investigated by experiments and a simulation model. The energy consumption was reduced with the decrease in the induced air volume and in the coke breeze content in raw mix. Under the condition of maintaining the sinteryield more than 60%, the lower limit of the energy consumption was achieved at an induced air volume of 9Nm³/m²min, and a coke content of 2.6 wt% in sinter mix. This condition corresponds to the heating to the maximum temperature of more than 1250°C and the holding at high-temperatures above 1100°C over 5min.
For the improvement of the utilization efficiency of oxygen, that is, the reduction of unit air volume, the application of the double ignition sintering was investigated. Under the conditions of the high bed height and high suction pressure, the sinter productivity reached to about 57t/m² D and a slight reduction of energy consumption was accomplished, if the sinter strength values of 50 to 60(TI) are allowable.

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The kinetics of reduction of thin (136μm) flat hematite specimens by He-H2 gas mixtures were investigated at 310 and 377°C in a thermogravimetric apparatus. The values of the rate constant k_s for the interfacial reaction were determined from the experimental weight loss data. These were combined with the previous results for reduction with pure hydrogen to obtain the following relation:
log/k_s=-1.484(±0.106)-3172(±72)•T^-1
(k_s: g•atm O•cm^-2•s^-1•atm^-1)
The activation energy was found to be 60745 (±1380), J•mol^-1 which is in reasonably good agreement with the published results. The reduction of hematite conformed to a first-order behavior with respect to hydrogen partial pressure. The scanning electron micrographs of reduced specimens showed “star-shaped” pore formations with the pore-sizes significantly larger than those observed in specimens reduced with pure hydrogen.

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Equilibrium between solid Fe-Cr alloy and H₂-H₂S gas mixture was measured by the gas circulating method to determine the activity of sulfur in the alloy at 1573K.
An isothermal section of the Fe-Cr-S system at 1573K was experimentally determined over the metal/sulfide equilibrium region with the conventional silica capsule technique. The thermodynamic evaluation procedure on the basis of the modified Gibbs-Duhem integration was applied to the tie-line distribution and the phase relations obtained experimentally, which results in a stability diagram, revealing the stable fields of the metal and sulfide phases as functions of the partial pressure of sulfur and the metal ratio. The solubility of sulfur in the Fe-Cr alloy was also determined.

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An exact solution and an approximate solution have been derived for the columnar dendrite model proposed by Ohnaka, ⁸⁾ in which a solidification rate, equilibrium distribution coefficient and diffusion coefficient in solid are assumed to be constant throughout the solidification. By comparing with the exact solution, it has been shown that the approximate solution has good accuracy. Further the model is extended on the basis of the derived approximate solution by incorporating a thermal model of solidification. The extended model includes multi-component alloy accompanying phase transformation in solid and temperature dependence of diffusion coefficients, and excludes the assumption of a given solidification rate. The calculated results of the extended columnar dendrite model agreed well both with the available experimental data and the calculated results of the extended planar dendrite model proposed previously. The assumption of the solidification geometry is unimportant for quantifying the microsegregation effects.

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In view of ionic theory, a subregular solution model for cations was applied to evaluate the thermodynamic properties of complex slags. The slags studied are Fe_tO-CaO, Fe_tO-SiO₂, Fe_tO-CaO- SiO₂ and Fe_tO-MgO-SiO₂ systems. The influence of slag composition on the activity of iron oxide and the ferric to ferrous iron ratio have been discussed.
It has been confirmed that the subregular solution model is satisfied over the wide composition range in above slag systems. The iso-activity contours of iron oxide in Fe_tO-CaO-SiO₂ and Fe_tO-MgO-SiO₂ slaps in equilibrium with liquid iron at 1600°C have been calculated using the subregular solution model.

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Hot and cold model experiments were made to find out the effect of pulverized lime injection on the reaction rate during the reduction period of refining of stainless steel melt.
The reduction rate of chromium oxide and the desulfurization rate were measured by the use of a 5t test converter and an 85t top- and bottom-blown converter. The capacity coefficient for reduction of chromium oxide, which proceeds on the permanent reaction site, is proportional to ε^0.84, where ε is the input rate of stirring energy into steel melt. Desulfurization proceeds on both of the permanent and transitory reaction sites. The capacity coefficient for desulfurization in the permanent reaction site is proportional to ε^0.82, while that in the transitory one is proportional to ε^-1/3 H (m/W_m)^1.5, where H is the depth of bath and (m/W_m) is the injection rate of pulverized lime per unit weight of steel melt.
In the cold model experiment with iron powder injection, gas holdup in mercury was measured by means of the electroresistivity probe technique. The upward flow velocity of the mixture of gas, liquid and solid is proportional to the cubic root of ε.
The effects of the operation factors such as m, H and gas flow rate, q, on the desulfurization rate were analyzed under the consideration of the two reaction sites. The ratio of desulfurization rate in the transitory site to that in the overall one increases with increases in m/W_m and H, and with a decrease in q. Moreover, the relation between q and H was calculated in the lime injection practice whose desulfurization rate was equal to that without lime injection on the basis of the experimental results.

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Flow field induced by a rotating electromagnetic field in a round billet has been analyzed in terms of the kW model of the turbulence. On the basis of the analyses, simple equations to predict stirring velocities and wall shear stress have been derived. Experimental study was made to validate the analyses.

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Using a steam oxidation testing apparatus, operating under almost the same steam conditions as those in actual boilers, the influences of temperature and pressure (especially above critical pressure) on steam oxidation were investigated with austenitic heat-resisting steels such as SUS 347-HTB, 17-14CuMo, and the newly-developed 20Cr-25Ni and 22Cr-35Ni steels for advanced fossil steam plants.
Oxidation loss in weight increased with higher steam pressure and temperature. Increase of Cr and Ni contents improved the oxidation resistance. Cr concentration in inner scale increased with Cr content of steel. This caused the higher resistance to steam oxidation.
The existence of a Ni enriched layer at the scale and metal interface contributed to the improvement of steam oxidation resistance. The Ni concentration of the layer was higher in steels containing a higher Ni content.
Morphological investigation of the scale cross sections showed that considerably large amounts of voids and cavities were produced in the outer scale of SUS 347HTB and 17-14CuMo steels oxidized in steam at high temperature and pressure.

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From the point of suppressing the crack growth, an attempt to improve the resistance to fracture of ceramic matrix composites was made on Al₂O₃ matrix/tungsten fiber composite using triangularly waned fiber for the reinforcement.
On the monotonic loading flexure test, large plastic deformation was found with holding the maximum strength of the composite, where clear stepwise change in strength against deflection was observed on the load-deflection curve. These phenomena were seen under the condition that fibers were still unbroken.
Superior resistance to ratchetting of the deflection against cyclic loading was found on the cyclic loading flexure test, in comparison with straight fiber reinforced composite.
No delamination was observed on the Charpy impact test, where straight fiber reinforced composite exhibited serious delamination over the whole test piece.
Microscopic observation on the crack extension path clearly showed that triangularly waved fiber had a peculiar effect on suppressing crack growth by way of the branching or turning of the crack path.
Mechanism of the crack growth suppression was discussed from a point of the reduction of stress intensity factor induced by serious turning or branching of the crack path.

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The method of quantitative determination for in-depth profile analysis of chemical composition in coating layer of Zn alloy electroplated steel sheet using glow discharge emission spectrometry was investigated.
A suitable method for in-depth profile analysis of chemical composition was established in terms of integrated emission intensity. In the case of alloy electroplated steel sheet, the sputtering rate and atomic emission rate depend upon the alloy composition. Therefore, the calibration method was improved by correcting the profile intensity.
Analytical accuracies (σ_d) were 0.78g/m² Zn, 0.45g/m² Fe for 5-50g/m² of Zn-Fe alloy coating weight, and 0.23g/m² Zn, 0.03g/m² Ni for 3-20g/m² of Zn-Ni alloy coating weight. This method is used in the analysis for the production control of a factory.

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