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X-ray photoelectron spectroscopy was used to study a lead-based relaxor dielectric ceramic to identify the grain-boundary phase most likely to be responsible for the insulation degradation of relaxor dielectric ceramics under humid loading conditions. The grain-boundary phase consisted mainly of lead and oxygen. The binding energies of Pb4f7/2 and O1s in the grain-boundary phase were found to be 137.3 eV and 528.8 eV, respectively, and these values agreed well with those for Pb3O4 and PbO2. In addition, the broadness of the Pb4f7/2 peak suggested the presence of PbO. Measurements were made of lead dissolution from dielectric ceramics in hot water; specimens with a grain-boundary phase gave a 30 to 50 times greater lead concentration in the hot water than specimens without a grain-boundary phase. This demonstrated that the grain-boundary phase easily dissolved in hot water. Thus, it was concluded that the grain-boundary phase contained water-soluble PbO2 and PbO. The results strongly supported the resistance degradation mechanism of relaxor dielectric ceramics under humid loading conditions as previously proposed by the authors.

Diamond thin films have been formed on molybdenum substrates with a mixture of methane and hydrogen gas using the electron-assisted chemical vapor deposition (EACVD) method. The surface morphology, crystal structure and composition of the films obtained were characterized by scanning electron microscopy, reflection high energy electron diffraction and secondary ion mass spectrometry. The experimental results revealed that substrate heating is necessary to eliminate the hydrogen atoms occluded into the film during the course of diamond deposition. The hydrogen is frozen in the film without the substrate heating. This may prohibit the rearrangement of the carbon atoms in the film and will produce an amorphous film.

The reaction of [RhL4]ClO4 (L=2,4,6-Me3C6H2NC and t-BuNC) with an equimolar amount of iodine yields a trans adduct, [RhI2L4]ClO4. The rate of this reaction in acetonitrile was measured employing a stopped-flow technique under pseudo-first-order conditions with excess iodine. The result indicates that the reaction proceeds via an intermediate which is presumably assigned to cis-[RhI2L4]ClO4, followed by intramolecular isomerization to the trans adduct.

The reaction of Rh(dtc)L2 (dtc=S2CN(CH3)2, L=2,4,6-(CH3)3C6H2NC) with an equimolar amount of iodine yields a trans adduct, RhI2(dtc)L2. The rate of this reaction was measured in benzene, employing a stopped flow technique under pseudo-first-order conditions with excess iodine. The result indicates that the reaction proceeds via a charge transfer complex Rh(dtc)L2·I2, which is rearranged in two consecutive zero-order reactions with respect to the I2 concentration; the rearrangement of Rh(dtc)L2·I2 to a cis adduct followed by isomerization to the trans adduct. This mechanism is supported from kinetic data for the reaction of Rh(acac)L2 (acac=CH3COCHCOCH3) with I2. It is also described that RhI(I3)(dtc)L2 and RhI(I3)(acac)L2 were obtained by reactions of Rh(dtc)L2 and Rh(acac)L2 with excess iodine, respectively.

Corrosion properties for three kinds of hafnium have been examined in 10.5 MPa steam at 773 K. Nuclear grade hafnium formed a shiny black film with a few white nodules, which were found to be monoclinic HfO 2 . Hydrogen pick-up fraction during the corrosion amounted to ca. 40% to produce hydrogen dissolved in the hafnium matrix with evolving the remaining 60% hydrogen as H 2 gas. Sponge and crystal bar hafnium were also examined and they showed superior and inferior corrosion resistance, respectively, to nuclear grade hafnium. The corrosion resistance for hafnium increased with increasing the iron content involved in hafnium for these three kinds of hafnium and, correspondingly related to the density of iron-containing second phase particles, which were characterized to be face centered cubic Hf 2 Fe. The corrosion mechanism, which was previously proposed for Zircaloy nodular corrosion, was adopted with making minor alterations, to explain the hafnium corrosion properties.

An image processor has been fabricated to examine out-of-pile nodular corrosion for Zircaloy-2 tubings. The covering fraction, which is the percentage of the nodule occupying area on the Zircaloy surface, was measured with the processor. The covering fraction showed a strong correlation with the weight gain at any corrosion time of this experiment. The correlation observed can be explained by a model for the lenticular shape of the nodules. The image processor also gives unfolded pictures of the whole Zircaloy surface. By analyzing the picture, the location of the nodules generated was found to be determined in an early stage of corrosion. New nodules were not produced later, and the nodules only grew larger with time.

Zircaloys undergo nodular corrosion in 10.5 MPa steam at 773 K. The corrosion was found to proceed via formations of zirconium dioxide, zirconium hydride and H2 gas. Clarification of the role played by the H2 gas has provided a corrosion mechanism wherein the ZrO2 film is broken to initiate nodular corrosion, when the pressure of the H2 gas accumulating in the ZrO2-Zircaloy interface exceeds the pressure the ZrO2 film can withstand. The mechanism can explain lenticular shape of nodules. Examination of influence of heat treatment and texture on the corrosion behavior supported the presumed mechanism. In connection with the mechanistic studies, second phase particles of Zircaloy have been identified.

[Rh(t-BuNC)4]ClO4 undergoes oxidative addition reactions with Ph3SnX (X=Cl, Br) to give cis-[Rh-(Ph3Sn)X(t-BuNC)4]ClO4. The adducts partly dissociate in solution to exist as an equilibrium mixture with the Rh(I) substrate and the addendum. Kinetics of the equilibrium reactions in three different organic solvents were studied spectrophotometrically under pseudo-first-order conditions with excess Ph3SnX. Rate constants for the forward reaction (kf) are strongly dependent on the solvent polarity; kf increases in the order of 1,2-dichloroethane