The selection of stainless steels to prevent stress corrosion cracking (SCC) in hot sodium hydroxide solution containing small amount of sodium sulfide was determined by order of the critical temperature of SCC occurrence and by the electrochemical behaviour. SCC susceptibility of stainless steels might be governed by chemical compositions, the nickel and chromium content.It was possible to presume that SUS 310S had enough resistance to use in industry.
In comparison with SCC behaviour of SUS304L conducted with various SCC test methods, the detecting SCC was able to reproduce with not only the Lehigh restraint test but also the slow strain rate tensile tests at the same test conditions as in the U-bend test.

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From the corrosion aspect, there are increasing demands for stainless steel clad plates consisting of corrosion resistance alloys superior to stainless steels of a conventional class such as type 304 or 316.Fundamental study was carried out on effects of chemical compositions and thermo-mechanical conditions for hot-rolling on sensitization to corrosion, to develop type 310 suited for the clad plate production.Optimum conditions for the 310 clad plate rolling were also studied.Based on these consideration, a great success in manufacturing the 310 clad plates of superior corrosion resistance even after thermal cycles such as normalizing, welding and stress relieving has been made.

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Metal fine-particles were prepared by adding hydrazine to aqueous solution containing paradium and copper ions.The prepared fine particles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The measured diameters of the prepared particles were in the range of 2 to 100nm and independent of reaction temperatures.The constituent of the particles measured by EDS was found to be determined only by the ion constituent in the solution.XRD analysis of the prepared particles revealed that they were solid solution consisting of paradium and copper.Further, XRD analysis suggested that an amorphous stucture would be contained in the products.

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This presents a theoretical analysis on the transient response of an inhomo geneous elastic layer subjected to a mechanical impulsive load.The closed-form solution for a delta impulse is obtained by making use of the Laplace transformation and convolution technique.
The response to a gaussian impulse is formulated from linear superposition of the exact fundamental solution for the delta impulse.
Deduced expressions to the gaussian impulse are estimated numerically for two cases of inhomogeneous layers such as the functionally gradient materials of SiC-C and SiC-TiC.These transient wave forms are compared with the form propagating inside a homogeneous SiC layer. Then, it is found that, as the time flies, the wave forms are distorted and the intensity of the wavefront reduces gradually because of the effects of the inhomogeneity of the layer.

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In attempt to obtain chemically pure and homogenous product, a wet chem ical method has been applied to synthesize zinc oxide varistor, which is marketed by sintering after mixing of powders by a ball mill.Efficient yield was attained for precursors by a precipitation method using zinc acetate and zinc acetyl ace tonate as starting materials with praseodymium oxide and cobalt chloride as additives.Calcination process, crystalline size of zinc oxide, additives distri bution and voltage-current curve were characterized by thermogravimetric analyzer, reflected right microscope, SEM-EPMA and varistor tester.The samples sintering over 1200°C showed a decreasing tendency of the grain size of zinc oxide with the increase of praseodymium content.Uniform distribution of praseodymi um was observed for the samples obtained by the wet chemical method, especially for the samples with calcination before sintering, rather than the samples ob tained from zinc oxide and praseodymium oxide powders by using a ball mill.
Non-linearity of voltage-current curve was observed for the both samples of ZnO-PrO₂ obtained by a wet chemical and a conventional ball-mill methods. The non-linearity, however, was not observed for a cobalt-added sample except for a sample containing high cobalt content obtained by a wet chemical method.

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A manganese oxide type Au adsorbent was prepared by heating a mixture of MnCO₃and Ag₂CO₃ (or Ag powder) at 390°C for 4.5 hours. At present, there are many papers on separating or recovering Au from various Au solutions. In these papers, activated carbon, chelate resin and algae were principally used as the adsorbent for separating or recovering Au. However, as far as the author has investigated, papers on manganese oxide type Au adsorbents have not been published to date. The author has been studying a manganese oxide type Li adsorbent, and the knowledge was applied in preparing a manganese oxide type Au adsorbent. The composition of the Au adsorbent was analyzed as Mn0_3.4 Ag_0.15. The x-ray diffraction pattern showed weak intensity peaks at 30.8, 36.7 and 65.36 as 2θAvalues.
This adsorbent was activated by acid treatment, and adsorbed the Au-Cl complex ion selectively from an artificial geothermal water (1mg/lAu). The enrichment ratio of Au in the first 10ml eluted from the adsorbent saw a 375 fold increase over the initial concentration (1mg/lAu). Additional elution yielded a result of 4.52mg/g Au adsorbed per unit weight of the adsorbent. The adsorbent also adsorbed Ca and Mg ions. The property of the adsorbent to adsorb Ca and Mg ions with the objective ion, is similar to the properties of manganese oxide type Li adsorbent. Thus, it is considered that this property is a common property among manganese oxide type adsorbents.

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In order to study the effects of surface pickling in acid solution and test atmosphere on the fatigue strength of an ultra-low carbon steel (Interstitial free steel), the reversed bending fatigue tests were carried out under a bending stress range of 140-340MPa in air and Ar atmospheres.
The results obtained were as follows.
(1) The fatigue life for the test in air strongly depended on the time of pickling in the acid solution. The life increased as the pickling time increased, however it did not depend on the pickling time for a time span of less than 10minute. The fatigue life for a10minute pickling time increased with decrease in bending stress and a fatigue threshold existed at around120MPa.
(2) The fatigue fracture surface showed that thecrack propagation process is dominated bx the formation of ductile fatigue striations and that the crack growth mechanism is a mixed mode of transgranular and intergranular.
(3) However, the crack growth process was mostly intergranular in surface region and gradually changed to transgranular in the interior region.
(4) The tendency of intergranular in the surface region was more distinguished in the longer pickling time and/or in air atmosphere.
(5) The micromechanism of intergranular was believed to be related to a combination of hydrogen atoms dissolved during the pickling and, oxygen atoms penetrating from the test atmosphere at the crack front in the grain boundary region.

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To evaluate effect of hydroxide and chloride ions on dissolution of iron and titanium, anodic polarization behaviour has been investigated in both xNaCl+yHCI and xHCIO₄+yHCI solutions (x+y=4.50kmol·m^-3). The anodic dissolution of iron in low [H⁺] -concentrated chloride and highly acidic-low [Cl^-] solutions can be interpreted by the hydroxide mechanism. On the other hand, it is explained by the chloride mechanism for highly acidic-high [Cl^-] and high [H⁺] -concentrated chloride solutions. The amount of adsorbed intermediate, ΔQ measured using a channel flow double electrode method increases with decreasing the concentration of [H⁺] in low [H⁺] -concentrated chloride solutions and increasing that of [Cl^-] in highly acidic-high [Cl^-] solutions. X-ray photoelectron spectroscopy shows that the hydroxide mechanism brings. γ-FeOOH and Fe₂O₃ as the final reaction products, while the products by the chloride mechanism are FeCl₂ and FeCl₃. The anodic dissolution of titanium is characterized that the hydroxide mechanism does not occur and hydroxide ions act as an inhibitor to the chloride mechanism.

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The preferential enrichment of noble gases in amorphous materials are discussed based on Xe in amorphous silica and Ne in natural glasses. For studying the enrichment of Xe in silica, silica samples generated by the leaching of rocks in acid geothermal waters were used in addition to those synthesized by the precipitation on some materials in neutral geothermal waters. Oxygen isotope fractionation factors between these amorphous silicas and geothermal waters indicate that silica samples from the acid waters also are generated in isotopic equilibrium with the water by the processes of dissolution and redeposition. Xe enrichments are observed in both silica samples from neutral and acid waters, in spite of no enrichments of other noble gases. The lower the precipitating temperature of silica, the higher the content of Xe in silica become. These Xe gases can be released at high temperature of 1100-1700°C. These observations seem to suggest that Xe is not adsorbed on amorphous silica but occluded in the framework or structure of the silica, of which the space is suitable for atomic size of only Xe in noble gases. On the other hand, Ne excess is a common feature generally seen in natural glasses such as obsidian, tektite, Darwin glass and submarine glasses. The release of Ne from these glasses can be taken place in the low temperature of 400°Cto 500°C, with a exception of tektite being degassed mainly at 1600°C. It is conceivable that the occurrence of Ne excess can be explained by diffusion into the glasses from the atmosphere based on the Ne isotopic data. The Ne excess has been produced by gas-solid interaction after the glasses solidified, because of high diffusivity of Ne. These Ne and Xe enrichments in silica and natural glasses and the difference between release patterns of noble gases from them indicate that only gas having suitable atomic or molecular size for the the frameworks and structures of materials can be preferentially occluded in them. Though noble gas enrichments have been reported only for the amorphous materials such as silica and glasses, it may be expected that such preferential enrichments of noble gases make a contribution to study the chemical and physical effects caused by gases occluded in crystalline materials.

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The thermomechanical properties of composite materials are influenced by various factors such as defects, reactions between matrix and fillers, orientation of fillers, mismatch of the coefficient of thermal expansion (CTE) between the matrix and the fillers.The effect of these factors on the thermomechanical properties of sintered composites is estimated theoretically and the theoretical evaluations are compared with the experimental data.The theory used in this calculation is based on Eshelby's equivalent inclusion method, with which we can solve the three-dimensional elastic problem by assuming ellipsoidal fillers to be embedded in an infinite elastic body.This method applies to various types of fillers by changing the aspect ratio of the ellipsoidal fillers such as: long fibers, whiskers, spherical particles and so on.Within this formalism, we have analyzed the effects on the thermomechanical properties of composites of interface debonding between matrix and fillers, dispersion of pores, phase reactions among constituent phases, anisotropically dispersed fillers, residual stress induced by shape memory effect, and CTE mismatch between matrix and fillers.
The microstructure of the sintered composites, can be controlled widely by changing the mixtures of powders, sintering conditions and the heat treatment, thereby we can obtain specimens with a variety of thermomechanical properties. In this study, the microstructural parameters for Eshelby's analysis have been determined directly from microstructural observations of the composites, and the thermomechanical properties have been predicted theoretically using the observed data.We have got an excellent agreement between the experimentally determined thermomechanical data and the theoretical predictions.It has been shown that the present method will be a versatile tool for the analysis of the properties of the sintered composites, as well as for their material design.

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The recent trend of FRAM (Ferroelectric Random Access Memory) including Y1 (Bi₂SrTi₂O₉) is reviewed with special reference to crystal structure, spontane ous polarization, ferroelectric hysteresis loop, memory-cell structure, and vari ous methods for synthesizing ferroelectric thin films. The size effect, induced by grain size, domain structure, crystal structure, soft mode, and other factors, is discussed based on the data of powder ceramic processing. Further, nearly size effect-free ferroelectric thin films obtained by artificial superlattice oxides are introduced. To obtain a high performance FRAM as a ferroelectric non volatile memory, it is indispensable to accomplish (i) the enhancement of ferro electricity, (ii) the improvement of fatigue, and (iii) the microstructural control of cell structure with 1 transistor/1 capacitor.

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