Low-Pressure Solubility and Diffusion of Hydrogen in Zirconium

Low‐pressure solubilities were determined for H in α‐ and β‐Zr and in two Zr‐O alloys at 700°–1000°C and pressures of 0.1–4 µ Hg. The data followed Sieverts' law for each phase, and H solubility decreased with increasing temperature at a given pressure. Also, there was a slight increase in H solubility in α ‐Zr with increasing oxygen content. Diffusion coefficients for H in α‐Zr were obtained in the range 300°–600°C by analysis of prepared concentration gradients. In the range 600°–800°C, degassing coefficients were determined from rate of H evolution from Zr cylinders. Degassing coefficients were much lower than expected from diffusion theory, and it was concluded that the degassing was not a pure diffusion phenomenon. Terminal solubilities obtained from the gradient analysis were in good agreement with those found by previous investigators.