Improved extraction-separation could be achieved in the extraction of alkali, alkaline earth and rare earth metal ions using macrocyclic ligands as ion size selective masking reagents. By adding macrocyclic ligand to the aqueous phase in the conventional chelate extraction system, the extractions of metal ions with larger ionic radii shifted to the higher pH region. Consequently, the separation among the metal ions was enhanced. Diazapolyoxabicyclic ligands (cryptand) exhibit a prominent separation ability for alkali and alkaline earths metal ions. Quantitative separation systems have been successfully developed in the synergistic extraction of alkali and alkaline earth metal ions in the presence of cryptand. A new type of water-soluble sulfonated crownethers have been prepared. The extractive separability of lanthanide ions was found to improve by adding the sulfonated crown ethers into the aqueous phase. The number of water molecules in the first coordination sphere of the central Eu³⁺ in the complex was determined by a laser-induced luminescence study. In addition, fluorescence spectra were measured to evaluate the structure of the complexes. The stabilization of the complexes formed is discussed taking into account an outer-sphere electrostatic attraction between the sulfonic acid group and the metal ion.

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In order to understand the quenching crack phenomenon in cast steel, a disk shaped low alloy cast steel specimen having a opening was quenched in water at 1123K. The behavior of a quench crack was investigated by microstructure observation and analyzed by the Heat treatment CAE software. The results obtained are as follows. (1) The quench cracking easily occured as the volume of specimen increased. The mass effect for quenching crack was significant. (2) The quench cracking was due to time lag in martensitic transformation at surface side and inner side of the quenched specimen, but not due to the thermal stress in the specimen. (3) The behavior of a quenching crack was able to be predicted by the Heat treatment CAE software. (4) Therefore, the Heat treatment CAE software is useful for a counterplan preventing the quenching crack.

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The purpose of this study is to clarify slurry-erosion mechanism of silicon particle reinforced aluminum alloy base in-situ composites. Using a series of specimens (pure Al, hypoeutectic of Al-7mass%Si, fully eutectic of Al-12.6mass%Si and hypereutectic of Al-20mass%Si, Al-30mass%Si and Al-40mass%Si), slurry erosion test was conducted for 1.26×10⁵s (35h) at 293K under a constant slurry speed of 8.55m/s. Sand volume fraction of the slurry was changed from 5 to 40vol. %. After the slurry erosion test, amount of weight loss in the specimens was measured to clarify the slurry erosion behavior. The results obtained are as follows. (1) The amount of weight loss depended on strength of the specimens in whole range of sand concentration in the slurry for pure Al and hypoeutectic specimens. (2) And also, the amount of weight loss depend on the sand concentration in slurry and/or the Si concentration in the matrix of the alloy for fully eutectic and hypereutectic specimens. The hypoeutectic specimen showed high slurry-erosion resistance for lower sand volume fraction in the slurry, though the hypereutectic specimen for higher sand volume fraction in the slurry. (3) Therefore, it is important to understand that the slurry erosion behavior depends on a combination of the microstructure of materials and the environmental condition such as sand concentration in the slurry.

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An empirical method has been proposed to correlate the reaction rate constants in mixed liquid solvents based on the Arrhenius equation. A Redlich-Kister type excess function is introduced to obtain the excess activation energy in the mixed solvent. The rate constants for isoprenemaleic anhydride reaction in dilute solution of the hexane + nitrobenzene mixture previously reported was examined. It is found that the present model can correlated the reaction rate constants with a good agreement.

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