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We previously researched whisker growth from solder, and reported that whiskers occurred from a non-corroded tin layer that was sandwiched between the non-uniform progressed corroded tin layers in a high-temperature and high-humidity atmosphere.Here, we report further on the results obtained from the EPMA analysis and the electrochemical properties. First, it was ascertained that the corrosion of tin was promoted as bromine in the ux invaded the solder. Furthermore, in addition to the high-temperature and high-humidity environment, oxygen was found to be indispensable for the generation of whiskers, and to nally change into tin oxide through tin hydroxide.In addition, from an experiment that varied the temperature while maintaining a uniform relative humidity, it is understood that the activation energy was 0.84 eV when whiskers were generated from the solder. Also, an experiment that changed the relative humidity while maintaining a uniform temperature revealed that a plot of the whisker-generating time forms a straight line on a semi-log plot for the reciprocal number of the relative humidity.

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The surface oxide layer of Fe-Cr-Al alloy was modified for use as the metal support of SOFCs. The Fe-Cr-Al alloy was firstly coated with LSCF and pre-heat-treated in a vacuum at 1000 °C for 1 h. In comparison with heat treatment at 700 °C, in which the surface oxide was identified as columnar γ-Al 2 O 3 /Sr 3 Al 2 O 6 , durability was greatly improved while maintaining electric conductivity at the same level. High-resolution STEM/TEM analysis revealed that the morphology was a similar columnar structure arranged in the same direction. The primary component was α-Al 2 O 3 polycrystal (>80%) and the secondary component was Sr 3 Al 2 O 6 (∼15%). After the formation of columnar γ-Al 2 O 3 /Sr 3 Al 2 O 6 in the low temperature range (<800 °C), γ-Al 2 O 3 was transformed to a more stable α-Al 2 O 3 by increasing the temperature to 1000 °C. Ionic diffusion paths, which cause growth of the oxide during operation, were reduced in the columnar structure. Electronic conduction similarly occurred for both γ