The aqueous oxidation of zinc sulfide in diluted hydrochloric acid was carried out in order to obtain fundamental data on acidic leaching conditions.
Deaerated hydrochloric acid of pH 1∼3 and of 10⁻¹∼1 mol/L Cl⁻ was used as acidic media. The amount of zinc sulfide powder suspended in the acidic solution was 10⁻²∼10⁻¹ mol/L . The solution was set under certain temperatures between 25°∼60°C and stirred at 600 rpm.
Results obtained from the experiment were as follows:
(1) The main dissolution reaction of zinc sulfide in acidic media was of the type of hydrogen sulfide formation and showed a parabolic behavior. The reaction was of diffusion control.
(2) The influence of pH to the dissolution rate of zinc sulfide was linear and the rate of dissolution was decreased with increasing value of pH.
(3) The presence of chloride ion positively influenced the dissolution of zinc sulfide, especially at high temperature.
(4) The relation between the dissolution rate of zinc sulfide and the unit surface area of the ore powder suspended was almost linear. The rate was proportionally increased with increasing area of ore powder.
(5) The dissolution rate of zinc sulfide was large at the initial stage and then decreased with the lapse of time. The rate of dissolution of zinc sulfide was probably decreased with the coexistence of Zn²⁺ in the solution.

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Time decrease of permeability (disaccommodation) was studied on the ceramic Sr-doped YIG, Y₃Fe_5−xSr_xO₁₂ (0≤x≤0.08).
Two kinds of disaccommodations were observed; one (DA1) was at approximately −170°C and the other (DA2) was at approximately 50°C. The activation energy of DA1 for all specimens was 0.06–0.12 eV, which agreed well with that of electrical conductivity at low temperatures. The activation energy of DA2 was 0.7–1.2 eV, and from the compositional dependence of DA2 and the electrical properties on Sr concentration, it was concluded that Fe⁴⁺ ion induced by substitution of Sr²⁺ ion contributes to DA2 and Fe²⁺ ion to DA1.

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The electrodeposition of nickel-zinc alloys was performed using mixed solutions of nickel and zinc sulphates. The internal stress, composition, and crystal structure were investigated.
(1) The crystal structure of the deposits obtained were face-centered cubic, complex cubic and hexagonal close-packed, depending on the composition of the electrolyte and on the composition of the deposit.
(a) In the region of f.c.c. corresponding to the α-phase, the internal stress is tensile and its magnitude increases with increasing proportion of zinc in the deposit.
(b) In the region of c.c. corresponding to the γ-phase, the internal stress is compressive and its magnitude has a maximum when the proportion of zinc in the deposit is between 75 and 80%.
(c) In the region of h.c.p. corresponding to the η-phase, the internal stress is compressive and its magnitude increases in proportion to the content of nickel in the deposit.
(2) After the electrodeposition, the internal stress in the deposit was changed by holding the deposit in the air or by hydrogen discharge on its surface.
(a) The tensile stress in the alloy deposited as the α-phase increases when it is exposed in the air, and decreases by the electrodeposition of hydrogen on its surface. The change of internal stress becomes larger with increasing zinc content in the deposit.
(b) The compressive stress in the alloy deposited as the γ-phase decreases when it is exposed in the air, and increases by the electrodeposition of hydrogen on its surface.

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A study by means of an X-ray small angle scattering method was carried out on the structure and the growth of Guinier-Preston zones in a binary aluminum-6.8 at% zinc alloy. By the isothermal measurement of scattering intensities of the alloy aged at 40°C, it was found that both models for the structure of G.P. zones proposed by Walker and Guinier and by Gerold and Schweizer were not suitable at the early stages of aging, but that the latter model was suitable at the later stages. Moreover, the mechanism of growth of these zones was indicated to be accordant with the diffusion-controlled Ostwald ripening.

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A high-temperature cell assembly attached to a Hitachi Model EPU-2A spectrophotometer was constructed to measure the absorption spectra of fused salt solutions. The measurable spectrum range of this instrument is 50000 to 5000 cm⁻¹ over the temperature range from 300° to 890°C.
Absorption spectra of Pd(II) in fused LiCl–KCl eutectic were measured in the spectrum range from 29000 to 10000 cm⁻¹ at various temperatures between 400° and 700°C. Only one absorption band was found at 20200 cm⁻¹ and its molar absorptivity was 315 at 400°C. An increase in temperature caused both a shift of the absorption maximum to a lower wave number and an increase in molar absorptivity. Some discussions on the species of Pd(II) in this solvent are made in comparison of these results and absorption spectra of Pd(II) in aqueous solutions of high chloride concentration.

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Copper single crystals grown in vacuum (10⁻⁴∼10⁻⁵mm Hg) by the Bridgman method were subjected to the following three kinds of annealing treatments in vacuum (∼2×10⁻⁵mm Hg): (1) thermal cyclic annealing using a moving furnace, (2) thermal cyclic annealing using a fixed furnace, and (3) isothermal annealing. Changes in the dislocation distribution, the dislocation density, and the length of sub-boundaries per unit area with annealing time or annealing cycle were examined by means of the etch-pit technique.
Thermal cyclic annealing was much more effective than isothermal annealing in reducing the dislocation density and the length of sub-boundaries. Little differences were observed between thermal cyclic annealings using a moving furnace and a fixed furnace. Thermal cyclic annealing was more effective in crystals with large subgrains than in crystals with small subgrains.
In crystals with subgrains larger than a few millimetres, the dislocation density of the order of 10⁵/cm² was reduced to ∼2×10³/cm² by thermal cyclic annealing for about 100 hr with a period of 15 or 30 min.

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In the current investigation, the reduction kinetics of synthetic nickelferrite powder and pellet with hydrogen gas has been studied by a thermobalance method at temperatures between 400° and 900°C. The hydrogen reduction process of nickelferrite powder has also been examined by means of an X-ray diffractometer, infrared absorption spectra and a transmission electron microscope. The experimental results obtained are summarized as follows:
(1) The beginning point of the reduction of nickelferrite with hydrogen gas is about 315°C and the fractional reduction, R, of nickelferrite increases parabolically with increasing reduction time. Furthermore, the reduction curves of the nickelferrite pellet in the range 0 to 80% in the fractional reduction are well represented by the experimental equation derived by McKewan, which is commonly used for the reaction controlled by the interfacial areas.
(2) Apparent activation energies on the hydrogen reduction of the nickelferrite pellet are 15.8 kcal/mol below 600°C and 9.1 kcal/mol above 600°C, respectively. The values agree well with those obtained previously for iron oxide.
(3) The rate of reduction of the nickelferrite pellet is proportional to the partial pressure of hydrogen gas at 500° and 700°C.
(4) According to the data obtained from X-ray analysis and infrared absorption spectra, it is obvious that the reduction process of nickelferrite with hydrogen gas may proceed in the order of the following steps; 3NiFe₂O₄+4H₂→3Ni+2Fe₃O₄+4H₂O and Fe₃O₄+4H₂→3Fe+4H₂O at 500°C, and 3 NiFe₂O₄+4H₂→3Ni+2Fe₃O₄+4H₂O, Fe₃O₄+H₂→3FeO+H₂O and FeO+H₂→Fe+H₂O at 700°C. The reduction products, metallic iron and nickel, finally form an iron-nickel alloy.
(5) From the observation under transmission electron microscopy, it is found that the reduction products formed by the hydrogen reduction of nickelferrite preferably exist as a complex mixture rather than the unit particles.

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Use of germanium coated substrates for electrodeposited permalloy thin films used as high speed memories remarkably improves the magnetic properties and their reproducibility. Effective features of the germanium coated substrates (germanium/silver/glass) were investigated in comparison with the silver coated substrates (silver/glass and silver/germanium/silver/glass), using a B-H loop tracer, an electron microscope and an X-ray diffractometer. The experimental results suggest that the advantage of germanium coated substrates comes from the amorphous structure of a germanium layer.

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The solubility of hydrogen in liquid pure copper and several liquid binary copper alloys has been measured by the Sieverts’ method or the sampling method. The alloying elements, Ni, Co, Fe, Mn and Te increase the solubility while Sn, Zn, S, P and Sb decrease it. The standard free energy of solution of hydrogen in pure copper for the reaction
(Remark: Graphics omitted.)
in the temperature range of 1096° to 1288°C obtained by Sieverts’ method is given by
ΔG°=10800+7.51T cal/g-atomH.

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Masumoto et al. have previously discovered that Ni–Mn alloys near in composition to Ni₃Mn exhibit a high magnetic permeability when an optimum degree of order is attained. These alloys are named “Nimalloy”. A series of experiments has been carried out on the effects of various additive elements on the properties of Ni–Mn alloys, and the highest initial permeability of 76000 and the highest maximum permeability of 441000 have been obtained in the Ni–Mn–Fe–Cr system. With increasing Ge and Nb additions to Ni–Mn alloys, both initial and maximum permeabilities at first increase slightly and then rapidly reach their peaks, after which the values decrease gradually. In the case of Ge additions, the composition of 77.89% Ni, 17.98% Mn and 4.13% Ge corresponds to the highest initial permeability of 15180, and the composition of 78.27% Ni, 17.11% Mn and 4.62% Ge to the highest maximum permeability of 167000. In the case of Nb additions, the highest initial permeability of 32500 and the highest maximum permeability of 151000 have been obtained with the composition of 77.55% Ni, 19.52% Mn and 2.93% Nb.

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Mg–Sn alloys rapidly quenched from the liquid state were examined by X-ray diffraction. A metastable phase of the face-centred cubic structure was obtained in the composition range between 14 and 18 at% Sn, corresponding to 2.28 and 2.36 (s+p) electrons/atom, respectively. The lower limit of the range coincides approximately with Engel’s empirical limit for the stability of FCC phase.
An intermediate phase tentatively analysed to be of an orthorhombic structure was obtained in the alloys richer in tin than Mg₂Sn.

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