speeds, zone lengths and numbers of passes were tried to know the optimum refining conditions. The impurity content was estimated from the residual resistivity, and the highest resistance ratio in bulk R300/R4.2 obtained in the present work was 50000.

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In order to study how the scattering anisotropy influences the dc size effect, measurements have been made on the orientation dependence of the size effect in dilute Al - Ag and Al - Si alloys at 4.2 K. The solute Ag decreases the relaxation time near the zone boundaries, while Si has a reverse effect. The surface orientations of the specimens were set parallel to the crytallographic planes {100} and {110} in the light of the anisotropic size effect found in pure Al. The axis orientation of the specimens (direction of current flow) was . The results show that the size effect in these specimens can be well described by means of the Fuchs - Sondheimer theory, with the specularity parameter p = 0 and the product of bulk resistivity and bulk mean free path . This is contrary to the theoretical prediction that the size effect in Al is sensitive to the anisotropy of the relaxation time due to the impurities.

Characteristicsof pit initiation of SUS 304 L and SUS 316 L stainless steels were studied using iodine solutions in which triiodide ions (I3-) accumulate with time due to the dissolution of metal between 333 and 363 K. The pit initiation process of SUS 304 L and SUS 316 L stainless steels followed exponential laws. It was found that a stable pit growth in the triiodide solution occurred when the pit depth reached 0.1mm regardless of temperature, the initial triiodide concentration and materials. Stable pit growth had a tendency increasing linearly for SUS 304 L and exponentially for SUS 316 Lwith time.