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A TiO 2 film was deposited onto alumite using an electrochemical technique, where the initial electrodeposition was carried out by ac electrolysis in (NH 4 ) 2 [TiO(C 2 O 4 ) 2 ] solution, followed by pulse electrolysis in TiCl 3 . This is a new method to prepare a mesoporous TiO 2 photocatalyst film consisting of nanosized particles and to directly fix them onto the alumite substrate (Al/Al 2 O 3 ). The sizes of the TiO 2 particles in the prepared film were about 5 nm, and they consisted of mixtures of the anatase, rutile, and amorphous phases. This film had a high catalytic activity for the decomposition of acetaldehyde even under fluorescent lamp illumination. Moreover, the preparation cost is very low compared with other methods. Therefore, the prepared Al/Al 2 O 3 / TiO 2 plate is very useful for the practical photodecomposition of chemical contaminants in the atmosphere. The mechanisms of the TiO 2 deposition and the photocatalysis are discussed.

Ionic conductivities of yttria-stabilized zirconia (YSZ) single crystals deformed at high-temperature were measured by the AC impedance method. A correlation between ionic conductivity and dislocation structures of deformed YSZ single crystals were investigated. Electrical conductivity measurements of the deformed YSZ crystals were performed for two different current directions of [1 1 10] and [ 1 1 1 11]. The [1 1 10] direction is parallel to edge dislocations introduced by the primary slip system, while the [ 1 1 1 11] direction is normal to the edge dislocation lines. Transmission electron microscopy observations showed that the dislocations due to the primary slip system of (001) [110] were mainly generated at the strain of around 1% strain, while the secondary slip systems, such as (1 1 1 1 1)[101] and (1 1 11)[011], were also activated at about 10% strain. It was found that the deformed samples with larger strains exhibited higher electrical conductivities irrespective of the measured current directions. However, the electrical conductivity along [ 1 1 1 11] was higher than that along [1 1 10], suggesting that mobility of oxygen ion is sensitive to the dislocation structures. From the activation energy for oxygen diffusion in the deformed samples, it was found that the oxygen migration enthalpy for deformed samples became smaller than that for undeformed samples, whereas the association enthalpy for the deformed samples became larger. The increase in the association enthalpy might be due to interaction between oxygen vacancies and dislocations. It is thus considered that oxygen vacancies concentrate around dislocations, and are able to move very quickly along the dislocation lines.

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