Nickel sulfide hollow whisker formation

Hollow, high-aspect-ratio nickel sulfide whiskers were formed during aqueous corrosion experiments at 250 degrees C by the U. S. Department of Energy. The whiskers grew radially from Teflon thread at the waterline in acidic sodium sulfate solutions containing chloride additions. The hollow morphology is consistent with that reported for the mineral millerite found in nature in hematite cavities. The data suggest that iron and chloride impurities are necessary for the observed whisker structure. (C) Elsevier Science Inc., 1997.