ANOMALOUS BEHAVIOR OF SOUND-VELOCITY AND ATTENUATION IN LIQUID FE-NI-S

The compressional wave velocity in molten iron containing 5 percent ni ckel and 10 percent sulfur increased with increasing temperature. This anomalous behavior was determined to be attributable to-the presence of sulfur, which conditions the formation of large molecular units in the liquid. Temperature-induced breakup of macromolecular units result ed in greater packing efficiency and an increased velocity. Ten percen t sulfur increased attenuation by one to two orders of magnitude compa red with liquid iron, Such behavior at outer core pressures and temper atures would constrain the velocity gradient in the outer core and wou ld enable the discrimination of potential light alloying elements.