Technique to determine solute diffusion coefficient and partial pressure simultaneously

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A simple technique to measure simultaneously the diffusion coefficient and the partial vapor pressure of a solute in a homogeneous solid solution is presented. The analysis is based on the mathematical solution of the diffusion equation for a cylindrical system with a solute loss term at the cylinder surface. The magnitude of the loss term is proportional to the solute concentration at the surface. Three zirconium rods, one with 3 at. % Sn, one with 5 at. % Sn, and one with 4 at. % Ti, were treated in vacuum at 1875 K for 7, 5, and 2.5 h, respectively. Results from these specimens indicate that Sn and Ti both diffuse via a vacancy mechanism in β-Zr. Also, the Sn–Zr bonds appear to be much stronger than the Sn–Sn bonds, whereas the Ti–Zr bonds seem to be a little weaker than the Ti–Ti bonds.

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