Rapid Report on Diffusion Measurement of Liquid Pb(t-x)SnxTe using the Sounding Rocket TR-IA 4

Abstract

In order to obtain the -true- diffusion coefficient of liquid Pbc1-x)SnxTe, a microgravity experi­ment was conducted using the Japanese sounding rocket, TR-1A 4. The diffusion couple (Pbo.sTe-­ Pb0_7Sn0_3Te) of a 2 mm diameter column was melted and kept at 1277 K followed by quenching with injecting helium gas. The diffusion during heating and cooling periods was taken into account in an analytical solution of Fick's second law with the assumption of D = AT 2 (A is constant). The diffusion coefficient at 1277 K was obtained as 7.9 X 1-0 9 m2/s for the present, which is larger than a calculated value from the diffusion coefficient of 1227 K obtained by TEXUS rocket experiment with the assumption of D = AT 2 (A is constant). The results of detailed analysis are to be presented in the near future.