Some recent developments in the applications of thermodynamics to problems is physical metallurgy have required adaptation that are in the inventive spirit of classical thermodynamics. Diffuse interfaces and the problems that crystal lattices pose are taken as examples.

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The enhancement of magnetization intensities in Na- and K-β″-ferrites by annealing in a chalcogen (S, Se) atmosphere was studied. Although Na- and K-β″-ferrites were changed to Na- and K-β-ferrites by annealing in a Se atmosphere (P_ΣSe=31.4 kPa) at 1073 K for 1 h, the high magnetization intensities of 50 and 63 μWbmkg⁻¹ respectively, were first obtained in Na- and K-β-ferrites. The enhancement of magnetization intensity is resulted from Se absorption into ionic conduction layer. It was indicated that Se atoms may occupy in two sites on the ionic conduction layer, because its TG curve showed two steps desorption process. K-β″-ferrite annealed at 1273 K in a Se atmosphere decomposed to cubic spinel and α-Fe₂O₃ phases, on the contrary, the K-β″-ferrite annealed in a S atmosphere decomposed to only the cubic spinel phase.

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Crystallographic and magnetic properties of Ir–Mn–Sn alloys have been investigated by means of X-ray diffraction and magnetic analysis. It has been found that a new L2₁-type Heusler alloy of Ir_1.8Mn_1.2Sn exists in the Ir–Mn–Sn system in the composition range of Ir_2−xMn_1+xSn for 0.2<x<0.4. The lattice parameter of this system is from 0.6204 nm for x=0.2 to 0.6189 nm for x=0.4, the magnetic moment is from 3.2 to 2.6μ_B/Mn and the Curie temperature is from 342 to 265 K. The lattice parameter of the Ir_1.8Mn_1.2Sn compound is 0.6204 nm, magnetic moment 3.38μ_B/Mn at absolute zero degree and the Curie temperature 342 K. The magnetization and the Curie temperature of these alloys decrease with increasing x.
The C1 type ordered alloy has been obtained near the composition of equi-atomic ratio for a fairly wide composition range, but magnetic character are much different from the other ferromagnetic alloys of the C1-type.

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The atomic structure around ferric ions of the ferric hydroxide Fe(OH)₃ in aqueous solution has been studied by the anomalous X-ray scattering (AXS) and EXAFS methods. It is found that this ferric hydroxide consists of the FeO₆ octahedral unit structure and these octahedral units are connected with the edge and double-corner sharing linkage. On the other hand, the powder of the present ferric hydroxide prepared by freeze-drying the aqueous solution was also studied by the conventional X-ray diffraction method. The atomic structure of ferric hydroxide powder is also found to consist of the FeO₆ octahedra connected with the edge and double-corner sharing linkage. Referring to the crystalline structures of other ferric hydroxides and oxides, it is predicted that the FeO₆ octahedral chains formed by the edge sharing linkage are connected with the double-corner sharing linkage in the present ferric hydroxide Fe(OH)₃ solution and powder. The number of the double-corner sharing linkage in solution is about 60% of that in powder. This implies that the solution structure is characterized by the octahedral chains with a relatively large amount of vacant space.

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Differential scanning calorimeter (DSC) investigations and tension tests at 773∼848 K have been carried out in four different superplastic Si₃N₄/Al–Mg–Si composites. The DSC investigations revealed that the melting point of each composite was lower than the melting point of its matrix alloy. This is probably attributed to local melting due to segregation of solute atoms near the matrix/reinforcement interfaces. The optimum superplastic temperature for each composite, where a maximum elongation was obtained, was close to its melting point. Therefore this suggested that superplastic elongations are obtained in metal matrix composites within the solid-liquid region because the presence of a liquid phase at the reinforcement/matrix interfaces serves to relieve the stress concentrations due to sliding and thereby restricts the development of internal cavitation.

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In order to lay a foundation of a potentially efficient separation procedure for copper in hydrochloric acid solutions, we have investigated the adsorption of copper and several characteristic impurity elements on a strongly basic anion exchange resin in a wide range of HCl concentration. Further experiments were carried out to determine the HCl concentrations and activities in the resin phase. The initial increase of the obtained equilibrium distribution coefficients with increasing HCl concentration indicates the formation of negatively charged complex ions. This tendency of the adsorbability functions is generally reversed at higher HCl concentrations. Analysis of the ion exchange equilibrium based on the obtained adsorbability and activity functions in the higher HCl range provided an interpretation of anion exchange behavior and pointed out the probable average charges carried by the stable, exchangeable species. Possible associations of the examined ions have also been taken into consideration. Comparison of the adsorbability functions showed sufficiently large differences to allow effective purification of initially monovalent copper in chloride solutions, and the obtained average charge of the Cu(I) species can be applied to loading considerations.

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In view of the application of sodium carbonate slag to the elimination of Sn from molten copper, the thermodynamic properties of NaO_0.5–CO₂–SnO₂ slag have been studied by conducting the following experiments:
(1) Activities of NaO_0.5 in the slag were determined by the EMF method using β″-alumina as a solid electrolyte over the composition range of 1>N≥0.795{N=n_Na⁄(n_Na+n_Sn), n: the number of moles} under the partial pressures of CO₂ of 0.001∼0.08 MPa at 1423∼1523 K. It was found that the activity of NaO_0.5 did not depend on the slag composition for the constant partial pressure of CO₂ and the slag was saturated with Na₂SnO₃(s).
(2) Then the solubility of Na₂SnO₃(s) into sodium carbonate melt was measured under the various partial pressures of CO₂ and oxygen at 1523 K. With decreasing partial pressure of CO₂ the solubility increased, but the partial pressure of oxygen had no effect.
(3) Activities of SnO₂ were determined by the distribution equilibrium measurements for Sn between the Na₂SnO₃(s)-saturated slag and molten copper. From the activity of SnO₂ combined with that of NaO_0.5, the standard free energy change for the following reaction was determined as:
2NaO_0.5(l)+SnO₂(s)=Na₂SnO₃(s)
ΔG°⁄kJ=−159(1523 K)
The activity of SnO₂ in the homogeneous liquid region of the slag was also evaluated by the distribution equilibrium measurements.
On the basis of the results obtained, the distribution ratios of Sn between the slag and molten copper were estimated. The ratios decrease with decreasing SnO₂ content in the Na₂SnO₃(s)-saturated slag. The higher oxygen partial pressure and the lower CO₂ partial pressure are more preferable for the removal of Sn from molten copper.

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In order to estimate the wettability between aluminum sheet and solder, the interfacial impedance response at the interface between solid aluminum and liquid lead or lead-tin alloy was measured. The sessile drop method was also carried out to compare the wettabilities at various temperatures. It was found that the impedance for the Al/Pb interface, the compensated impedance of external measuring circuit, consists of the parallel connection of capacitance and resistance. The capacitance value is about 0.02 Fm⁻² in the non-wetting interface of Al and Pb–Sn melts at the temperatures below 823 K. However, the capacitance changes to 4 Fm⁻² above 873 K, where good adhesion of the Pb–Sn alloy is improved and this is in good agreement with the result of the sessile drop method and the interface observation by scanning electron microscopy.

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Two thermoelectric materials, BiTe and BiSbTe were prepared by mechanical attrition of elemental powders in a rare gas atmosphere. Nearly 20 min were required for the alloying of BiTe, while 10 h were required for BiSbTe. After attrition, the average powder diameter of the BiSbTe alloy was in 1.4 μm, and the impurity content, measured by Inductively Coupled Argon Plasma Emission Spectrophotometer, was less than 0.1 mass%. The MA powders were sintered by a hot pressing technique. Uniform elemental dispersions were measured by EPMA in BiSbTe alloys sintered at 623 K.

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