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We investigated an electroless aluminum plating based on using AlCl3–1-ethyl-3-methylimidazolium chloride (AlCl3–EMIC) ionic liquid with diisobutyl aluminum hydride (DIBAH) as a liquid reducing agent. The plating film was analyzed by measurements of X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX) and glow discharge optical emission spectroscopy (GD-OES). Consequently, a thick aluminum plating film with high uniformity was prepared from AlCl3–EMIC with DIBAH. No impurity phases were detected. Moreover, we discussed the reaction mechanism of the electroless aluminum plating.

The negative electrode performance of the electroplated Al film electrode in the LiCl saturated AlCl 3 –1-ethyl-3-methylimizadolium chloride (EMIC) + SOCl 2 melt as the electrolyte for use in non-flammable lithium secondary batteries was evaluated. In the cyclic voltammogram of the electroplated Al film electrode in the melt, the oxidation and reduction waves corresponding to the electrochemical insertion/extraction reactions of the Li + ion were observed at 0–0.80 V vs. Li + /Li, which suggested that the electroplated Al film electrode operated well in the electrolyte. The almost flat potential profiles at about 0.40 V vs. Li + /Li on discharging were shown. The discharge capacity and charge–discharge efficiency was 236 mAh g −1 and 79.2% for the 1st cycle and it maintained 232 mAh g −1 and 77.9% after the 10th cycle. In addition, the initial charge–discharge efficiencies of the electroplated Al film electrode were higher than that of carbon electrodes. The main cathodic polarization reaction was the insertion of Li + ions, and side reactions hardly occurred due to the decomposition reaction of the melt because the Li content corresponding to the electricity was almost totally inserted into the film after charging.

We investigated a series of bulk, ceramic samples of Si-added bismuth layered-structure compounds, SBTS, prepared by alloying SrBi2Ta2O9 with Bi2SiO5 or Bi4Si3O12 using a solid-state reaction method. X-ray and neutron powder diffraction were carried out to determine the crystal structures. Structural information is correlated with the measured data of the ferroelectric properties. We find that remanent polarization and coercive electric field increase with the addition of Bi2SiO5 or Bi4Si3O12 in SrBi2Ta2O9. The dielectric constants of SBTS increase markedly with increasing temperature. It is found that the ferroelectric behavior is related to the distortion and tilting of the TaO6 octahedron that are effected by variations in Bi and Si contents, respectively, in the SBTS samples.

We investigated the dependence of the properties, crystal structure and electrode characteristics on the heat-treatment of Li1.052Co1/3Ni1/3Mn1/3Oy. The crystal structure was determined by X-ray and neutron diffractions and Rietveld analysis. The electron density images were calculated by MEM/Rietveld analysis using X-ray diffraction. The discharge capacity increased, but the cycle performance was not good after a high PO2 heat treatment (450°C, PO2 2.03 MPa, 48 h, annealed). On the other hand, the cycle performance was improved by a reduced heat treatment (450°C, Ar, 48 h, annealed). Based on the crystal structural analysis, the bond length between 3b (transition metal site) and 6c (oxygen site) decreased with heat treatment in the reduction direction. From the distributions of the electron density, the (Li,Ni)[3a] site was localized and the covalent bond of (Co,Ni,Mn,Li)[3b]–O[6c] was weak due to the high PO2 heat treatment.

We investigated the preparation and characterization of the Pb–Zr–Ti–Nb–Si–O ferroelectric thick film by the electrophoretic deposition method. A ferroelectric material of (Pb,Si)(Zr1−x−yTixNby) Oz was prepared by the solid state method. The obtained samples were single phase, and the metal composition was controlled. The powder was charged into the acetone-iodine based electrodepositon bath after it was ultrasonically suspended. The maximum amount of the deposit was obtained when 1.5 g/l I2 and 5.0 g/l ferroelectric powders were added to a 100 ml acetone bath, and a uniform coating was obtained with an applied voltage at 180 V. The thickness of the film was controlled by changing the deposition time. The heat treatment condition of the deposited thick film was investigated and the conditions were 1000°C, O2, and 120 sec. The obtained thick film was relatively dense and uniform with a thickness of 15–30 µm at center position. Furthermore, the microstructure of the thick film was homogeneous. Based on these results, we obtained relatively good P-E hysterisis loops using Nb substituted Pb–Zr–Ti–Nb–Si–O thick films.

We investigated the relation between the cycle performance and crystal structural change during the charge–discharge process of LiMn 1.5 Ni 0.5 O 4 as a 5 V class cathode active material, which was prepared by changing the calcination temperature using the sol–gel method. The lithium content of Li 1− x Mn 1.5 Ni 0.5 O 4 ( x =0.5, 0.7, 1.0) was controlled by electrochemical lithium extraction. The crystal structure was determined by Rietveld analysis using powder neutron diffraction. As a result, all samples consisted of three phases (space group: P 4 3 32) of different lattice constants and Ni valences. The main phase, which has the maximum percentage, was shifted to a phase with a lower lattice constant with the decreasing lithium content, and then finally Li 1− x Mn 1.5 Ni 0.5 O 4 ( x =1.0) was almost oxidized to Ni 4+ by a charging process. Furthermore, LiMn 1.5 Ni 0.5 O 4, , by changing the synthesis temperature, was different for a few oxidation processes; the structure of the phase at Ni 3+ was not stable based on the distortion of each phase and the Madelung energy. It was suggested that these factors should provide an effective cycle performance.

We investigated the relation between crystal structure, electronic states and electrode performance of LiMn2-xMxO4 (M = Zn, Ni etc.) as cathode materials for lithium ion secondary batteries. The cycle performance is improved by substitution of Mn with M. The crystal structure was determined by Rietveld analysis using powder neutron diffraction. The electron density distribution was obtained by XRD using MEM/Rietveld method. From the results, the stability of the host structure is important for cycle performance.

The enhanced reduction of hydrogen peroxide (H 2 O 2 ) and electrochemical current oscillatory phenomena during its reduction were observed on a mercury (Hg) adatom-modified Au polycrystalline electrode in alkaline, acidic and neutral aqueous solutions. The enhancement of the H 2 O 2 reduction was observed in the potential region from −0.2 to −0.6 V (vs. Ag ∣ AgCl ∣ KCl (sat.)). The enhanced reduction of H 2 O 2 was independent of the pH of the solution in the pH region from 3 to 10. The current oscillation occurred in the negative differential resistance potential region (−0.4 to −0.6 V). Its amplitude and the potential width in which the current oscillation was observed depended on the surface coverage of Hg on the Au electrode and the kind of anions in the solution. The observed enhancement of the reduction of H 2 O 2 and the current oscillation were explained by taking into account the local pH increase near the Hg adatom-modified Au electrode as well as the electrode potential-dependent electrocatalytic behavior of the adsorbed species of OH − (OH ad ) on the electrode surface.

Molybdenum sulfide (MoS2) particles comminuted in a planetary ball mill dry in air at various grinding media fractions were characterized by BET surface area, element analysis, XPS, XRD and catalytic activity. Hydrogenation of 1-methylnaphthalene (1-MN) is mainly conducted to examine the catalytic activity of the comminuted MoS2 in a batch type autoclave swung at 30rpm. Relation was investigated between the characteristics of the comminuted MoS2 and apparent volume fraction of grinding media.Specific surface area, XRD line broadening, O/Mo measured by XPS and hydrogenation of 1-MN had the maximum and S/Mo by XPS had the minimum at the apparent volume fraction of 0.72. Catalytic activity was not explained soley by the increase in surface area of the comminuted MoS2. The catalytic activity was well correlated with S/Mo and O/Mo measured by XPS, which showed that unsaturated coordination sites of Mo are active sites for hydrogenation of 1-MN. In the experimental conditions the lattice strain of (001) and (100) of the comminuted MoS2 was almost constant, whereas the crystallite size was about 1/5 of as-received MoS2 at the apparent volume fraction of 0.72.

The observation of the tunnel formed on D. C. etched {100} highly ordered aluminum and analysis of the tunnel shape have been performed by using the oxide replica method. The tunnel widths (Wi) were measured as a function of the tunnel depth (li) for the tunnels obtained by D. C. etching in AlCl3, HCl+AlCl3, NaCl+AlCl3, H2SO4+AlCl3, LiCl, NaCl and KCl aqueous solutions. As has already been reported regarding HCl solution, Wi tapered exponentially with li, i. e., log (Wi/W10)=a·li, where W10 is the tunnel width at the depth of 10μm from the tunnel entrance, in all solutions examined in this study. In HCl+AlCl3 solution, Wi tapered rapidly with li compared to the case of HCl or AlCl3 solutions. The rapid decrease in Wi with li, in HCl+AlCl3 solution was considered to be caused by the increase in the concentration of Al3+and Cl- ions in the tunnel, followed by the hindrance of electrochemical dissolution of Al. On the other hand, for the tunnel obtained in LiCl, NaCl, or KCl solutions, Wi tapered with li, at the same rate. It was considered that Li+, Na+, and K+ ions play the same role in the formation of the tunnel.

Superconductors, Tl2-zBa2Ca1.95Y0.05Cu3Oy, with variable Tl contents were prepared. We investigated the dependence of their properties, crystal structures and Tc on the Tl content. The Cu valence decreased with decreasing Tl content, 2-z, in the region of 2-z≥1.5 but increased in the region of 1.2≤2-z

O 2 reduction on Hg adatom-modified Au electrodes has been examined in acidic, neutral and alkaline solutions using cyclic voltammetry and the rotating ring-disk electrode technique. The half-wave potential for the O 2 reduction in 0.1 M NaOH solution was 0.15–0.2 V more positive on the Hg adatom-modified Au electrode than on the bare Au electrode. That is, the O 2 reduction was accelerated on the Hg adatom-modified Au electrode surface in the potential range from ca. −0.1 to −0.5 V, compared with the bare Au electrode. Moreover, the accelerated reduction of hydrogen peroxide (HO 2 − ) to OH − could be also observed in the same potential range. Thus, it was found that the O 2 reduction on the Hg adatom-modified Au electrode proceeds with the exchange of four electrons in a series of pathways leading to the formation of OH − [O 2 →HO 2 − →OH − ] in the potential region from ca. −0.1 to −0.5 V. In the potential region from −0.3 to −0.5 V, the reduction current of O 2 decreased from the diffusion limiting current corresponding to four-electron reduction of O 2 to that for two-electron reduction of O 2 . The efficiency for the four-electron reduction of O 2 depended on the surface coverage ( θ ) of Hg on the Au electrode surface, and the highest efficiency was obtained on the electrode with θ =0.24. The four-electron reduction current of O 2 decreased with decreasing pH of the solution. The reduction of HO 2 − to OH − ion and also its oxidation to O 2 in alkaline media were found to be accelerated on the Hg adatom-modified Au electrode. The observed acceleration of the reduction of O 2 is explained satisfactorily by taking account of the potential dependent adsorption of OH − on the Hg adatom-modified Au electrode.

The purpose of this paper is to interpret the enhancement of Tc and Jc by the replacement of cations and the change of excess oxygen content for Bi-rich 2212 system, (Bi2.1-xPbx)Sr2.0(Ca0.9Y0.1)Cu2.0Oy, especially in overdoping region. The bulk samples were prepared by coprecipitation method. In bulk samples, the c-axis and Bi+Pb valence decrease and Cu valence increases with increasing Pb content, x. Tc(zero) increases with increasing x in the single phase region. On the other hand, the c-axis and Cu valence increase and Bi+Pb valence slightly increases with increasing excess oxygen content, Δy. An optimum excess oxygen content which brought a maximum Tc(zero) was found to exist at each Pb content. Furthermore, in order to elucidate the effects of metal substitution and oxygen content on Jc of the Bi2212 system, the films with the same metal compositions were prepared by the spin coating pyrolysis method. From the results of highly orientated thin films, Jc increases with increasing excess oxygen content, Δy, in the oxygen doping region, while it increases or keeps constant in the oxygen overdoping region. According to the results, the metal composition and oxygen content are very important for obtaining the highest Tc and Jc.

The crystal structure of (Nd0.675Ce0.325)2(Ba0.664Nd0.336)2Cu3.00Oy is described as a modified YBa2Cu3Oy structure, in which the Y layer is replaced by a (Nd,Ce)2–O2 block. While the dependence of Tc on oxygen content differs among the rare-earth copper oxide superconductors, superconductivity appears in a range of y=9.12–9.14 in the present system. One of the reasons for this difference is related to the nature of defects associated with oxygen in the plane contained Cu. We studied the crystal structure of single-phase (Nd0.675Ce0.325)2(Ba0.664Nd0.336)2Cu3.00Oy samples of different oxygen contents by neutron powder diffraction and the superconducting properties by Tc measurements and chemical analysis. Over the y range where superconductivity is realized, the Cu valence changes from 2.32–2.33 but the Ce valence remains ca. +4. From Rietveld refinements of the neutron data, we found a direct correspondence between the oxygen content and the occupation of oxygen sites in the CuOδ plane. The average bond distances of Cu–O in CuOδ and CuO2 plane, (Nd,Ba)–O(16l) and (Nd,Ba)–O(16m) decrease with increasing oxygen content. Moreover, since the average Ce valence does not vary with respect to oxygen content, the average bond distances connecting the (Nd,Ce) site to its oxygen neighbors are almost constant. The calculated bond valence sum for the Cu(1) atoms in the CuOδ plane and the average Cu valence increase markedly with oxygen content.

The electrodeposition of the Nb3Sn alloy film from the Lewis basic NbCl5-SnCl2-EMIC melt (50 mol%

A co-deposited film consisting of activated carbon (AC) and ketjenblack powder (KB) particles was prepared using the electrophoretic deposition (EPD) method and utilized as the electrode for a capacitor cell. As a result of evaluating various organic solvents as the dispersion solvent for the EPD bath, it was found that the best deposition condition was obtained using acetonitrile (AN). However, there was the problem that the co-deposited film consisting of AC and KB particles had a poor adhesion. The co-deposited film fabricated by adding polyvinylidine difluoride (PVdF) as a binder to the bath was able to be used as the electrode for a capacitor cell. The specific capacitance per unit weight of the electrode was almost equal to that of the commercial sheet electrode.

The possibility of K + -β-ferrite as a cathode active material for lithium secondary battery was investigated. Discharge–charge characteristics based on the lithium insertion and extraction of K + -β-ferrite have been studied by constructing an electrochemical cell Li|1 M LiClO 4 PC|K 1.33 Fe 11 O 17 (K + -β-ferrite). The cyclic voltammograms for K + -β-ferrite were unchanged after 10 cycles of operation. The OCV (open circuit voltage) before discharge was 3.2 V vs. Li/Li + . The discharge potential maintained 2.3 V vs. Li/Li + up to ca. 200 mAh/g at 60°C under a constant current density of 0.1 mA/cm 2 . According to the chemical analysis, K + -β-ferrite at each discharge step certainly contained lithium, in agreement with the lithium content calculated by current integration. Lithium content y in K 1+ x Li y Fe 11 O 17 was increased up to 11. After discharge, the spinel blocks were disordered, whereas the layer structure still remained in the XRD pattern. Lithium ions seem to mainly enter into γ-Fe 2 O 3 layers (spinel blocks) of K + -β-ferrite, because alkali layers could practically contain only 1.5 alkali ions for Fe 11 O 17 . The cell voltage in charge increased up to 4.5 V vs. Li/Li + at 25°C. The potential during charge was lowered to 3.7 V by raising the temperature to 60°C. The XRD pattern of the cathode material at every step of charge was similar to that at 200 mAh/g of discharge. Degradation of discharge–charge characteristics was not observed after 10 cycles of operation.

The origin of inductive behavior in electrochemical impedance during metal deposition was discussed based on numerical analysis. Impedance was calculated by the modulation of adsorption coverage Δθ/ΔE as follows: 1/Z=AF+jωCdl, AF=aA1+aA2 Δθ/ΔE, Δθ/ΔE=aθ1(jωaθ2+1), where AF is admittance, Cdl capacitance of electric double layer, ω angular frequency, and ai constant. Results of calculation indicate that the following adsorption processes are related to inductive behavior in metal deposition: (i) adsorbed intermediate in consecutive reaction, (ii) cathodic adsorbed species as catalyst, and (iii) anodic adsorbed inhibitor.

Tl2Ba1.6Sr0.4Ca2Cu3O10+y(Tl-2223) superconductor coatings on Ag substrates were prepared using the electrophoretic deposition method. The Tl-2223 single phase was obtained by applying a high Tl composition of superconducting powder at the proper sintering conditions in order to prevent evaporation of Tl during the sintering process. Nominal Tl compositions of the superconducting powders were 2.00-2.50, which were stoichiometric and excess compositions. Electrophoretically deposited coatings using these superconducting powders were buried in the superconducting powder and sintered at 815°C for 6h in air. For the case of the nominal Ti compositions of 2.20-2.30, superconducting powders were used for the electrophoretic deposition, the Tl compositions of sintered superconductors were 1.80-1.87, the critical temperature (Tc, zero) was 110-112K, and these samples were almost single phase. On the other hand, Ag2O powder was electrophoretically deposited onto the Tl-2223 electrophoretic deposition coating. After heat treatment at 315°C for 2h, the Tl-2223 pre-sintered superconductor coating was coated with silver. It was then sintered at 815°C for 6h. Although they were not buried during the sintering process, the Tl compositions of the obtained samples were 1.81-1.83 with a Tc, zero of 111-113K. This silver coat acts to restrain Tl evaporation and protects the coating of the superconducting layer. Moreover, the critical current density (Jc) of silver coated superconductor coating was 67A/cm2 (77K, 0T) when a nominal Tl composition of 2.30 superconducting powder was used for the electrophoretic deposition.

Equilibrium structures of Li 2 CO 3 and K 2 CO 3 were calculated using ab initio molecular orbital calculations carried out at the Hartree-Fock (HF) level. Of the four structures considered for Li 2 CO 3 and K 2 CO 3 , the most stable was a structure with all five atoms in a plane. The harmonic frequencies were also calculated and found to be in agreement with the present Raman measurements. Structure factors, calculated from the ab initio data for each of the four structures considered, are compared with existing X-ray results.

The initial stage of dendritic growth by zinc electrodeposits has been studied by electrochemical scanning tunneling microscopy (STM) and computer simulation. Zinc was deposited on a highly oriented pyrolytic graphite (HOPG) electrode from a 0.01mol/L ZnSO4 solution. The zinc deposits (0.018C/cm2) grew predominantly near the step line on the HOPG. Initially, the height difference (dmax) between the highest part and the lowest part of the deposit and the average roughness of the electrode surface (Ra) increased rapidly with deposition time. It is therefore suggested that the roughness of the electrode surface increases rapidly in the initial stage of electrodeposition. The simulation reproduced the morphology of the STM image (0.02C/cm2, 20nm×20nm) and the distribution of deposit heights observed by STM agreed with the result of the simulation. It was therefore confirmed that the deposition model used in the simulation is appropriate at the initial stage of zinc electrodeposition.

Charge-discharge characteristics of Al/FeS 2 secondary cells using AlCl 3 -NaCl-1-butylpyridinium chloride (BPC) melts and AlCl 3 -LiCl-BPC melts were investigated at various temperatures. Cyclic voltammetry and ac impedance measurements were performed by using planar FeS 2 and FeS electrodes at 60-150 o C in two kinds of the basic AlCl 3 -NaCl-BPC melts: BPC-rich (17 mole percent (m/o) BPC) and BPC-poor (7 m/o BPC) melt. The charge-discharge characteristic dependence on temperature and melt composition was responsible not only for the change of the conductivity of the melt but also for the change of activation and diffusion processes for the electrochemical reactions which proceed on the FeS 2 electrode

Charge-discharge characteristics of Al/FeS 2 secondary cells using AlCl 3 -NaCl-1-butylpyridinium chloride (BPC) melts and AlCl 3 -LiCl-BPC melts were investigated at various temperatures. Cyclic voltammetry and ac impedance measurements were performed by using planar FeS 2 and FeS electrodes at 60-150 o C in two kinds of the basic AlCl 3 -NaCl-BPC melts: BPC-rich (17 mole percent (m/o) BPC) and BPC-poor (7 m/o BPC) melt. The charge-discharge characteristic dependence on temperature and melt composition was responsible not only for the change of the conductivity of the melt but also for the change of activation and diffusion processes for the electrochemical reactions which proceed on the FeS 2 electrode

The thin films of K + -β- and β″-ferrites have been prepared by dipping-pyrolysis process using potassium tert-butoxide and iron naphthenate. The films exhibited a significant decrease in impedance with an increase in relative humidity. In addition, the magnitude in impedance changes at 25°C was two or three orders and increased with a rise in firing temperature from 600° to 1000°C; that is, with the progress of the crystallization of β and β″ phases. The thin films with the composition of K 2 O·6.1Fe 2 O 3 showed the reversible changes in impedance with the humidity changes. The 95% response time to the humidity change from 43% to 80% RH was 10 s for the film with 1 μm thick obtained at 1000°C. The response time was remarkably shortened in the form of thin film.

Thin films of (K+, Na+)-β-ferrites were prepared by the partial replacement of K+ ion in K+-β-ferrite with Na+ ion to obtain a humidity sensing element having almost linear characteristic in terms of log-impedance vs. relative humidity, with humidity-sensitive characteristic controlled by changing the K+/Na+ proportion. Replacing 4mol% of K+ ion with Na+ ion yielded the thin films showing almost linear characteristic. The impedance of the film changed by more than two orders of magnitude with an increase in relative humidity. For a change in relative humidity from 43% to 80%, 95% of the total change was completed within a response time of only 10s. For the reverse change, the response time was less than 15s. These values were faster than expected. Further, the element had excellent durability in terms of humidity-sensitive characteristic. This suggests that thin films with an K:Na alkali ratio 0.96:0.04 is applicable to humidity sensors in terms of linearity in log-impedance change, magnitude of impedance change, response time and durability.

Observation of tunnels formed on D. C. etched {100} highly ordered aluminum and analysis of the tunnel shape near the tunnel mouth were performed by using the oxide replica method. The tunnel shape near the tunnel mouth was measured as a function of the tunnel depth (li) for the tunnels obtained by the D. C. etching in HCl, NaCl, AlCl3, HCl+AlCl3, NaCl+AlCl3, H2SO4+AlCl3, and HCl+NaCl aqueous solutions. The tunnel width (Wi) tapered exponentially with li, i. e., log (Wi/Wo)=a·li, where Wo is the tunnel width at the tunnel mouth, in all the solutions examined in this study. In the solutions containing H+ ions, the tunnel width increased with the increase in the tunnel depth near the tunnel mouth at depths of 4 to 5μm from the aluminum surface, followed by a decrease of the tunnel width at depths of 5μm or more. The degree of expansion of the tunnel width increased with increasing H+ concentration. This indicated that the increase of the tunnel width with an increasing tunnel depth near the tunnel mouth was closely related to the presence of H+ ions. Corrosion (Al→Al3++3e-, 2H++2e-→H2) of aluminum near the tunnel mouth, in which H+ took part, was suggested as the origin of the tunnel width expansion near the tunnel mouth. In HCl+AlCl3, NaCl+AlCl3, and H2SO4+AlCl3 aqueous solutions, the degree of expansion of tunnel width decreased rapidly compared to the HCl and AlCl3 solutions. Al3+, Cl-, and H+ ion played an important part in determination of the tunnel shape near the tunnel mouth. The rapid decrease of the degree of the tunnel width expansion near the tunnel mouth was considered to be caused by the increase in the concentration of Al3+, Cl-, and H+ ion in the tunnel, followed by the hindrance of the electrolytic dissolution of Al.

Orthorhombic LiMnO 2 (o-LiMnO 2 ) was prepared as a cathode material for Li secondary batteries by the solid-state, sol-gel, and reflux heating methods. Reflux heating yielded a single phase whose composition we were able to control. The particle size distribution of this o-LiMnO 2 was uniform. Its discharge capacity at 25°C was the lowest and its cycle performance the most stable among the LiMnO 2 produced by the three methods. The discharge capacity increased with cycle number and stabilized at about 30-40 cycles at 25°C. We investigated the relationship between the Li + diffusion coefficient (D L i + ) and the crystal structure during the cycles. The D L i + for Li 1 - x MnO 2 at the stable cycle region is larger than that at the initial cycle and was almost constant during the charge-discharge process at 25°C. The D L i + at 30, 40 cycles corresponded almost exactly to that of the spinel Li 1 - x Mn 2 O 4 . Refinement of the sample was performed in 30 cycles by assuming two phases of space group Fd3m. The electron-density images suggest that the covalent bond of Mn-O was stronger for the sample synthesized by reflux heating than those synthesized by the solid-state method. The high-crystallinity o-LiMnO 2 leads to better stability and slower conversion to spinel LiMn 2 O 4 .

Variously shaped superconducting oxides with various substrates have been prepared by the electrophoretic deposition method. The maximum J c was about 600 A/cm 2 , because the oxides were fairly porous. Therefore, the deposition was attempted at high voltages for the substrate having a thermal expansivity close to that of the oxides. In the case of the stainless steel (19Cr-13Ni-3Si-0.1Nb), the superconducting phase did not have cracks, even if it was deposited at high voltage. Moreover, the preparation of BSCCO superconductor was studied by this method.

The preparation of Tl2Ba2Ca2Cu3O10+ x (TBCCO) superconducting oxide coating on Ag wire by the electrophoretic deposition method was investigated. Because it was the TBCCO powder is chemically stable in cyclohexanone, and a cyclohexanone bath (20 m l cyclohexanone+2.0 mg iodine+0.4 g TBCCO powder) was used. The deposited sample dried by hot air was sintered at 785° C for 10 min in Tl atmosphere, and T c,zero was 104 K. The superconductivity of the Tl2Ba1.6Sr0.4Ca2Cu3O10+ x (TBSCCO) coating was improved if the deposited sample was completely covered with a large quantity of TBSCCO powder to control the evaporation of Tl from the sample. When the sample was sintered at 815° C for 6 h, a uniform and approximately single high-T c phase coating was obtained with a T c,zero of 113 K.

BaTiO3 thick films on Pt substrates were fabricated by the electrophoretic deposition method. The suspension was prepared with fine powder (0.1 µm in diameter) of BaTiO3, acetone and iodine. Dense and strong films were formed in an applied DC field of 500 V/cm. The films sintered at 1200°C were crystallized into the tetragonal phase at room temperature. The coercive field E c and the remanent polarization P r were estimated to be 1.6 kV/cm and 2.1 µC/cm2, respectively, from the P-E hysteresis loop observation.

アミドブラック10B(AB10)の過酸化水素による退色が,アルカリ性においてコバルトの共存により著しく促進されることから,このことを利用した接触分析法による微量のコバルトの定量法を検討した.AB10の退色による吸光度変化を600nmで測定し,反応開始1分後と6分後の吸光度(A1,A6)の比の対数In(A1/A6)から反応速度に影響を及ぼすコバルト量を評価した.最適定量条件,pH12,タイロン6×10-3M,AB10 5×10-5M,過酸化水素0.25%で,5から30ppbのコバルトが定量でき,再現性は30ppbのコバルトに対し,相対標準偏差2.5%(n=6)であった.本法により,市販ニッケル試薬中に含まれる0.02から0.3%程度のコバルトを,特別な前処理もなく直接定量することができた.

The structure of the molten salt 50 mol% AlCl3–50 mol% NaCl has been investigated using the radial distribution function based on X-ray scattered intensity data collected at 200 °C and has been analysed by the correlation method. Using an analysis of the first peak of the radial distribution function it has been confirmed that the main ion existing in this molten salt is AlCl–4. The nearest-neighbour distances between the Al–Cl, Na–Cl, Cl–Cl and Na–Al pairs are 2.13, 2.80, 3.48 and 4.20 A, respectively. There are ca. eight NaAlCl4 units around each NaAlCl4 unit, with an average interunit distance of 6.98 A. These results are in good agreement with those obtained from a computer simulation using the molecular-dynamics method.

It is thought that the electrode kinetics of Al in a molten AICl3 + NaCl + KC1 electrolyte proceed by a three-electron reaction, but there is some doubt as to the existence of certain intermediate products. Thus rotating ring disk electrode (RRDE) measurements were carried out to analyze the electrode reaction and to confirm the existence of the intermediates. The disk electrode was of glassy carbon or 99.99% aluminum and the ring was of glassy carbon. When the disk was cathodically polarized at a sweep rate of 100 mV s−1 and the ring was potentiostated at a certain potential, two waves were observed on the disk polarization curve and a significant anodic current was detected at the ring as soon as the disk current reached the second stage of rise. The anodic ring current is considered to confirm the existence of the intermediates. The ratio of the number of electrons for the intermediate formation reaction on the disk to the number for the disappearance reaction on the ring was calculated to be 2. It is therefore assumed that Al(III) (i.e., AlCl4−) is reduced to Al(I) on the disk and that the Al(I) is oxidized to Al(II) on the ring. Some intermediates were also detected in the anodic reaction of Al, but the details are still under investigation.

The structure of molten 50 mol% AlCl3–50 mol% LiCl has been investigated using the radial distribution function based on X-ray scattered intensity data collected at 200 °C and analysed by the correlation method. The existence of AlCl–4 ion in this molten salt has been confirmed by an analysis of the first peak of the radial distribution function. The nearest-neighbour distances of the Al–Cl and Cl–Cl pairs are 2.15 and 3.50 A, respectively. There are approximately four AlCl–4 units around one AlCl–4 unit with an average interunit distance of 6.75 A.

The structures of AlCl3–n-butylpyridinium chloride (BPC) mixtures have been investigated using the radial distribution function (r.d.f.) based on X-ray scattered intensity data and have been analysed by the correlation method. By an analysis of r.d.f., it was confirmed that the AlCl4 tetrahedron is the fundamental structural unit in AlCl3–BPC melt. The nearest-neighbour distances of Al—Cl and Cl—Cl pairs for AlCl–4 in a 1:1 AlCl3–BPC melt at 60 °C and for Al2Cl–7 in a 2:1 AlCl3–BPC melt at 20 °C were 2.15 and 3.51 A, respectively. The Al2Cl–7 ion in a 2:1 AlCl3–BPC melt at 150 °C decomposed partly to AlCl–4 and Al2Cl6.

The corrosion behavior and corrosion resistance of electroformed nickel were investigated. The following experiments were conducted to confirm the singular feature of the corrosion of electroformed metals:(a) Immersion test(b) Measurement of activation energy for corrosion(c) Measurement of polarization curve(d) Electron microscopyThe following results were obtained.(1) The decreasing order of degree of corrosion of nickel specimens in acidic solutions containing Cl- was as follows: bright nickel>non-bright nickel>rolled nickel. However, the highest corrosion resistance was observed in bright nickel in HNO3. The above facts were explained by the studies on effects of co-deposited sulfur, true surface area of specimen, and effects of Cl-.(2) The difference between rest potential and corrosion potential was explained from the effects of adsorbed hydrogen and adsorbed Cl-.(3) The values of corrosion current density calculated from the amount of corrosion corresponded well with those values obtained from the polarization curves when the true surface area of the specimen was estimated.(4) There were three ranges in activation energies of corrosion; approximately, 1, 4-5, and 8.4-8.8Kcal/mol. These facts were interpreted by the discussion of hydrogen overvoltage, transfer coefficient, mechanism of anodic dissolution of nickel, and adsorption of Cl-.

The effects of anions and agitating conditions on the corrosion of 18-8 stainless steel were studied by immersion tests and measurements of polarization curves.The results obtained were as follows:(1) The amount of corrosion in Cl- solution was much larger than that in ClO4- or SO42- solution and it increased with the increase of Cl- concentration up to 19, 000p.p.m.The value of corrosion rate obtained from the polarization curves was in appreciably good accordance with that calculated by the immersion test for a long time.(2) It was explained that the rest potential varied with the lapse of time; in particular, remarkably in Cl- solution.(3) It was also explained that the temperature of Cl- solution and the agitating conditions of ClO4- or SO42- solution had great effects on the limiting current density for dissolution of iron. The effects of agitating conditions on the limiting current density for reduction of oxygen were theoretically analyzed, and the relation between the diffusion current (id) and angular velocity of rotation (ω) for a rotating cylindrical electrode was derived as follows;id=Aω1/2(4) The activation energy of corrosion was discussed and the singularity of Cl- was explained.

The way in which structure of molten AlCl3–NaCl mixtures changes with AlCl3 concentration and temperature has been investigated by x‐ray diffraction analysis. It was confirmed that AlCl4 tetrahedra are the fundamental structural units in the mixture of 50–70 mol % AlCl3. The nearest‐neighbor distance of the Al–Cl, Na–Cl, and Cl–Cl pairs were 2.13, 2.80, and 3.48 A, respectively. It was considered that the variation of the Q ⋅ i(Q) curves with AlCl3 concentration is due to the change of the mole ratio of AlCl−4 to Al2Cl−7 and the effect of the Na–Cl pair. It was supposed that AlCl−4 is tetrahedral and Al2Cl−7 is constructed from two corner‐sharing AlCl4 tetrahedra. Both the concentration of Al2Cl−7 and the coordination number of Cl around an Na increased with increasing AlCl3 concentration at constant temperature, but decreased with increased temperature. The structure of the melt changed with variation of temperature at constant AlCl3 concentration.