The theoretical relation between the thickness of the oxide-layer and the oxidizing time was discussed in the case of oxidation of cylindrical and sliced copper to Cu₂O in air at 990∼1045°C. Comparing the theoretical relation with experimental results, we obtain D=0.060exp[−(1.46±0.18)(eV)⁄kT] (cm²/sec) for the cylindrical specimen, and D=0.29exp[−(1.63±0.12)(eV)⁄kT] (cm²/sec) for the sliced one for the diffusion coefficients of ions in the oxide-layer. The obtained values for the activation energies and pre-exponential factors agree very well with those of cations in Cu₂O obtained by the tracer method. The order of magnitude of the pre-exponential factors can be also estimated quantitatively by the diatomic-chain model of an ionic crystal.
It is concluded that the above fomulas represent the diffusion of cations via the vacancy mechanism in Cu₂O formed on the metal and this diffusion determines the rate of oxidation of Cu to Cu₂O.

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Experiments were carried out to clarify the fundamental multiphase-diffusion behavior in Fe–Al alloys. At first, the etched structure and the hardness for each intermetallic compound in the alloys were examined in the normal state. For further observations, the diffusion couples prepared by the plating of Fe on the alloys were annealing at 800°C for several hours, and the diffusion couple with the alloy containing the Al phase was annealed at 610°C for 10 hr.
The experimental results revealed that the ζ phase (FeAl₂) had a smooth boundary with the α phase, and the η phase (Fe₂Al₅) transformed in the sequence of η→ζ→α. During the transformation of the η phase, however, a considerable amount of the ζ phase was observed between the η and α phases and the irregurality in the ζ-η boundary which was dependent upon the orientation of the original η phase was observed. With increase in Al content, in the η phase, a new η phase which protruded locally into the Fe layer appeared and consequently ζ phase was considerably reduced. The higher Al content alloy of the η_max+θ phase or the the θ+Al phase showed a local growth of the η phase, resulting in formation of the so-called bridges, the detachment of the plated Fe layer from the alloy substrate, and the formation of many voids in the newly formed η matrix.
In order to explain the above phenomena, the change in volume with the phase transformation and the effect of the anisotropy of the η phase were taken into account. Some calculations using the properties of the intermetallic compounds showed that above behavior would be ascribed to the high-diffusivity of Al atom released from the θ phase by the θ→η reaction or from the Al phase, and also to the creation of the new η phase at the Fe-Alloy interface.

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In order to elucidate the sulfidation behavior of pure iron at high temperature, kinetic studies were carried out as functions of sulfur pressure and temperature, and the sulfide phases of the scale formed were examined.
The sulfidation obeys a parabolic rate law, but the slopes of the log-log plots of sulfur pressures and corrosion rate constants change in the range 1/3.5 to 1/5.7 depending on the sulfur pressure.
The phases and preferred growth orientations of the scale were identified by the X-ray diffraction method. The results showed that the scale was composed of the pyrrhotite, troilite, and Fe₇S₈ phases, and that at higher pressures the (00l) planes were normal to the scale growth direction, while at lower pressures the (110) and/or (10l) planes were normal to that direction.
The SEM observation of the surface of the scale formed at 800°C revealed that the hexagonal step-like feature of the surface changed into a more flattened one with decreasing sulfur pressure.
From the growth mechanism of the scale it was evident that these sulfidation behavior was closely related to the vacancy configulation and diffusivity of iron ions in the scale and also to the adsorption of sulfur atoms on the particular sites of the scale surface.

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The sulfur distributions in the iron sulfide scale formed at 700°C under various sulfur pressures were determined by X-ray diffraction.
The gradient of the sulfur distribution in the scale is not linear, different from the results in the literature. A very sharp decrease in sulfur content and some flat range of composition of about 51.5 at%S are observed near the Fe/FeS interface and at the inner part of the scale, respectively.
The inter- and self-diffusivities of iron were calculated according to Fick’s second law and Darken’s relation as the function of distance and composition, based on the sulfur distributions and were an order of 10⁻⁶ and 10⁻⁸ cm²/sec, respectively. The self-diffusivity of iron was also calculated by use of several other methods and their results were compared with each other.
The extraordinary high diffusivities were obtained at the composition of about 51.5 at%S which corresponded well to the composition of the maximum value of a₀ parameter of FeS. This behavior may be attributed to the generation of the stress by deformation of the scale, the variation of the a₀ parameter with sulfur content in the scale, and also the annealing effect on the stress during corrosion.
The effect of the inner scale on the sulfur distributions in the outer scale was also examined and showed to result in the higher sulfur content in the outer scale.
The SEM observations of the inner scale fractured mechanically revealed the formation of voids in it, suggesting contours of the perforating dissociation of the outer scale crystal.

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The self-diffusion coefficients of silver and sodium ions in the whole range of concentration of silver nitrate-sodium nitrate melt have been measured by a capillary reservoir method. Both the self-diffusion coefficient of silver ion determined by the present work and the interdiffusion coefficient determined previously by C. A. Sjöblom at 315°C have almost same value up to 80 mole per cent of silver nitrate and the self-diffusion coefficient of sodium ion is slightly smaller than that of silver ion at 315°C. The five friction coefficients calculated from the values of two self-diffusion coefficients, the published values of the interdiffusion coefficient, transport function and equivalent conductance show the similarity of transport behavior between silver ion and sodium ion in silver nitrate-sodium nitrate melt.

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In a previous paper, it was reported that the high recrystallisation temperature of Cu–Cr, Cu–Zr and Cu–Zr–Cr alloys was due to the formation of fine precipitates during recrystallisation, which obstructed dislocation climb, glide and grain boundary migration.
In the present paper, the recrystallisation behaviours in Cu–Cr, Cu–Zr and Cu–Zr–Cr alloys quenched, tempered (at 350, 450, 500, 550 and 700°C), heavily cold worked and annealed at various temperatures were studied by the resistometric method, measurements of mechanical properties and transmission electron microscopy. No fine precipitates were detected at dislocations or sub-boundaries in the low temperature annealing stage, but fine precipitates, which retard recovery, must exist since electrical resistivity decreased during low temperature annealing. The mechanism of retardation of recovery is due to the binding of dislocation jogs by fine precipitates. In the high annealing temperature range, the growth of precipitates and crystal grains was observed by transmission electron microscopy and the effect of precipitates on the retardation of recrystallisation was also detected.
The size of precipitates formed during tempering before cold working did not affect the recrystallisation temperature, because the precipitates were broken up by heavy cold work and were thus made a constant size.

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The effects of temperature, strain rate and oxygen in interstitial solid solution on the yield and flow stresses at low temperatures of alpha Ti–O alloys with 0.04∼0.45 at%O were studied to ascertain the rate controlling dislocation mechanism. The effect of interstitial oxygen atoms on the thermal component of the flow stress increases with decreasing temperature. The relationship between the thermal component of the flow stress, σ₀^* at 0°K and oxygen concentration, C is well-ruled by σ₀^*=0.24μ₀\sqrtC, where μ₀ is the shear modulus C₆₆. The Gibbs free energy of activation for plastic flow is 1.10 eV (0.154μ₀b³) at 530°K regardless of the oxygen concentration. The experimental data are utilized to construct a force-activation distance curve, yielding f_im^*=63×10⁻⁶ dynes and x^*=1.5b, which are in accord with the thermally activated overcoming of interstitial oxygen atoms by dislocations as the rate controlling mechanism.

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Several reports have hitherto been submitted in relation to the studies on R(Cu, Co)₅ cast magnets in which Co is substituted by Cu in RCo₅ series permanent magnet alloys. The purpose of the present study is to put the anisotropy on the ternary alloy and to produce it with less expensiveness by a practical utilization of the chill-cast process, and to examine the relations between the magnetic properties and the microstructures. That is, the specimen is subjected to a heat-treatment at specific temperatures in Ar atmosphere for 1 hr either in the as-cast state or at 300∼1200°C; thereafter, the changes in the magnetic properties and in the microstructures, etc. are examined on both furnace-cooled specimens and air-quenched specimens. The results are given as follows:
(1) In the cast state, the ternary composition (Ce–MM)CuCo₄ exhibited the most conspicuous chill effect, and the values for magnetic properties were 4πI_r⁄4πI_10K=0.96 and (B·H)_max=5.5MG·Oe.
(2) In the heat-treated specimens, a comparison between the furnace-cooled and air-quenched specimen revealed that the magnetic properties of the latter were to those of the former. That is, by heat treatment at 500°C for 1 hr the (Ce–MM)CuCo₄ alloy exhibited 4πI_10K=5450 G, 4πI_r=5200 G, _IH_C=3700 Oe and (B·H)_max=6.0 MG·Oe.
(3) The specimens heat-treated at temperatures higher than 800°C exhibited snake-like I-H curves. By means of X-ray diffraction, the Ce₂Co₁₇ phase was newly detected in addition to the CeCo₅ phase, which may be considered as a cause for forming the I-H curves.

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The chlorination of high-titania slag to give titanium tetra-chloride is of growing importance. The present work was done to study the effect of some factors on the chlorination process in presence of solid carbon as a reducing agent. The factors involve the temperature, flow rate, and particle size. A synthetic slag near in composition to the natural slag obtained from reduction smelting of titani-ferrous ores was chlorinated in a fluidized bed silica reactor. A pre-chlorination step was necessary to get rid of the non-volatile chlorides causing the sticking and agglomeration of fluidized slag particles.
It was found that the temperature and flow rate of Cl₂ greatly affect the chlorination rate with points of maximum effect. Different particle sizes give distinctly different conversion curves with the smaller size giving higher conversion. The energy of activation was obtained from the Arrhenius plot as 19400 cal/mol.

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The effects of niobium on the cold-rolling and recrystallization textures in low carbon steel sheets were examined using X-ray techniques and electron microscopy. In the hot-rolled strips containing niobium, numerous precipitates about 150Å in diameter were observed. These precipitates had an effect on the cold-rolling textures to increase the {111} component with cold reductions up to 75%. The {111} component decreased abruptly and the {211} ⟨011⟩ component increased for reductions greater than 75%. The recrystallization textures could be closely related to the cold-rolling textures. The recrystallization textures changed continuously from {554} ⟨225⟩ to {211} ⟨011⟩ along the loci of the R.D.-60°⁄⁄⟨110⟩ fiber texture with the cold reductions prior to annealing. It was also found that fine precipitates retarded the recrystallization and inhibited the appearance of the (110) [001] component.

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The extraction equilibrium of Eu(NO₃)₃ from aqueous solution into Versatic acid 911-benzene solution was studied. The vapor pressure of benzene in this binary organic solution was measured by the transpiration method at 15, 25 and 35°C. And the activity coefficient of Versatic acid 911 in this solution was calculated by the Gibbs-Duhem equation.
On the other hand, the distribution equilibrium of Eu³⁺ ion between aqueous and organic solutions was measured at the above-mentioned temperatures by using a mixture of Eu¹⁵² and Eu¹⁵⁴ as the radioactive tracer. The composition of extracted species and the equilibrium constant of extraction were determined by taking the calculated values of activity of Versatic acid 911 into consideration. Furthermore, enthalpy and entropy changes of the extraction were calculated in the following way:
Extracted species: EuR₃·4RH
ΔH°=15.4(kcal/mol) ΔS°=37.8(e.u.)

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High density zircaloy-2 rods containing B₄C particles (5800 ppm) were fabricated by hot swaging.
In the case of the rod swaged with small-sized B₄C (−600 mesh), B₄C particles were found to be continuously distributed along the grain boundary of zircaloy-2 matrix, while in the case of the rod swaged with large-size B₄C (+200 mesh), B₄C particles were present sporadically.
ZrC and ZrB₂ were found to be formed in the rod swaged at 1000°C, while no reaction products were found in the rod swaged at 800°C. The examination of the properties by various testing methods such as corrosion testing, metallography, and hardness change measurement after annealing have indicated the characteristics that depend on the manufacturing condition and the size of dispersed B₄C particles.

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