A praseodymium-added zinc oxide film was successfully obtained by dip coating using zinc acetate dehydrate and praseodymium oxide as starting materials with ethanol as a solvent and one of ethanol amines as an aid for film preparation.
Several sets of ethanol amines were examined for their thermal decomposition and crystallization of zinc oxide to find the optimum condition for the film preparation. In order to obtain the uniform and dense structure of zinc oxide film, a coating solution should be prepared to contain diethanol amine/zinc molar ratio=1. Calcination in an oxygen stream was necessary to remove organic residues after each dipping. Smaller average value and narrower size distribution of grain were observed for the zinc oxide film compared to a disktype praseodymium-added zinc oxide prepared by a precipitation method.
Appreciable non-linear characteristic was confirmed in voltage-current for the zinc oxide film obtained.

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By use of a microscopic fracture model, a computational estimation method of bending strength of ultra fine-grained cemented carbides was developed on the basis of micromechanics. A macroscopic breakage of the cemented carbides was supposed to occur when a matrix crack, which generated from a defect in ultra fine-grained cemented carbides, extended unstably. In this paper, ultra fine-grained cemented carbides which contained vanadium carbide and chromium carbide were examined, and then η-phase in them was paid attention as defects. In order to evaluate the stability of the extension of the matrix crack. stress intensity factor was introduced. After the amount of the η-phase was related to the carbon content of ultra fine-grained cemented carbides under the concept of material balance, the bending strength was estimated. The estimated results were in good agreement with the experimental ones. The effects of the carbon content of carbides and the average size of η-phase on the bending strength were also examined. The results were presented in the figures and its application to material design was discussed.

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Graft copolymers of Poly [(2-vinylpyridiniu bromide-co-vinylalcohol)-gacrylamide] were prepared by the reaction of acrylamide with Poly (2-vinylpryidinium bromide-co-vinylalcohol). The flocculating abilities for 5% aqueous kaolin suspension were investigated in the relation to the structures by measuring the sedimentation rate, the sedimentation volume and the turbidity.
The results obtained are as follows. 1) For every graft copolymer, the optimum copolymer concentration required to flocculate 5% kaolin suspension was 40-80ppm. 2) Suitable mole fraction of acrylamide (F_AM), and that of quarternary ammonium salt group of 2-vinylpyrdine (F_Q2VP) in copolymer required for flocculating abilities was respectively 0.75, and 0.17. 3) Suitable pH values for the floccculating action were in the broad range of about 2 or below-12 or above. 4) While an isoelectric point was found in the vicinity of pH 4.6, optimum flocculating ability was observed in the pH range of 6-10. 5) Copolymers were more effective for typical commercial flocculants such as Sumifloc FC, PAS-A and Himoloc Neo 600

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Losses in the production of zinc is a serious problem. Zinc alloy is difficult to work with since it is a brittle metal. In spite on this, it has already been successfully industrially produced for use in super plastic alloys (SPZ). The rate of workability however is low. The present report therefore aims in presenting basic data on the workability of zinc alloy. A third metal element was added to Zn 22mass%Al binary alloy. The third element investigated may be V, Cr or Mn. The experiment resulted in an alloy which shows high-speed super-plasticity. From the facts described above, zinc alloy is given a new usage.

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The effect of the some additions on the electrical properties of the BaTiO₃-based dielectrics have been investigated. The addition of every additives decreased the dielectric constant. Cr₂O₃ and MgO improved the temperature dependence of dielectric constant. But, the addition of NiO, Co₃O₄ and MnO didn't improved the temperature depen-dence.
Dielectric constant of MgO added sample is 2600, but that of Cr₂O₃ added sample is 2400. We thought this difference is caused the formation of hexagonal BaTiO₃. The Cr₂O₃ added sample contained hexagonal BaTiO₃, though MgO added sample contained only tetragonal BaTiO₃.

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Stress corrosion cracking (SCC) of solution-treated Al-Zn-Mg alloy was mainly examined in 0.2N-H₂SO₄+7.2×10^-3M-NaCl (Solution-A) and 0.4N-H₂SO₄+2.4 x 10^-3M-NaCl (Solution-B) solutions in relation to pitting potential, crack initiation sites and crack morphology. Pitting potentials (Vc) obtained from current-time curves under various potentials were at-0.78V in solution-A, and at -0.68V in solution-B. The time to fracture decreased with an increase of applied potential in both solutions. It seems that the critical potential for SCC corresponds to the pitting potential under stress (V'c σ). Transgranular SCC was observed in both solutions. The crack directly initiates on the surface in the range of V'cσ-Vc, and initiates at the bottom of pits in the range of Vc-Vc* (potential which crack growth rate equals to pit growth rate). Mechanical fracture occurred in the potential above Vc*. Cracks initiating from the bottom of pit stops growing below the protective potential (E_R). Therefore, it is necessary for SCC that dissolving pits be present. The crack path is at the grain boundary at pH=3.3 depending on the pH, however, crack and pitting potential does not exist at pH=5.8.

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For a further understanding on the effect of grain sizes on the mechanical properties of OFHC-Cu and α brass, a dead load creep test of OFHC-Cu (grain size 0.040mm and 0.076mm) and 7-3 brass (grain size 0.022mm and 0.118mm) was conducted at elevated temperatures (from 523K up to 723K) using different loads. Rupture time and creep curves of OFHC-Cu and 7-3 brass were obtained. The creep strength of OFHC-Cu remained independent of grain size. Creep strength of 7-3 brass, however, showed, a very different value. Equi-cohesive temperature appeared in 7-3 brass, but did not in OFHC-Cu. OFHC-Cu showed an irregular creep curve due to the dynamic recrystallization at a large value of the Zener-Hollomon parameter.

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Effects of Ti content on the reaction products of Al₂O₃-Kovar joints were studied using active filler metal. The variation of microstructures of reaction products formed at the interface between Al₂O₃ and active filler metal was investigated by scanning electron microscopy, auger electron microscopy and xray diffraction. Increace of Ti content in the active filler metal improves shear strength of Al₂O₃-Kovar joints brazed at 1123K for 900s and addition of 8.lmass% Ti improves shear strength about 40% at the same brazing condition. Reaction layer (TiO) containing higher Ti content were formed in the interface between active filler metal and Al₂O₃ and these reaction layers are attributed to higher shear strength of Al₂0₃-Kovar joints.

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Supercritical fluid technology has been received much attention in many fields. Supercritical fluid is a compressible fluid above its critical temperature and pressure, which has dissolving power comparable to that of liquid and has transport properties intermediate between gas and liquid. The unique physical properties of supercritical fluid can be advantageously utilized in environmentally benign separation, reaction, and material processing. Applying supercritical fluids to various systems and processes is attractive both from an academic and an engineering point of views. In this paper, reaction characteristics in supercritical fluids and their application are reviewed.

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