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GAS PHASE HYDROGEN TRANSPORT IN ZIRCONIUM
Abstract
Commercially pure zirconium was machined into hollow cylinders of various radius ratios and wall thicknesses. Steady state permeation rates as well as transient rates of permeation were determined with a quadrupole residual gas analyzer at temperatures between 800(DEGREES)K and 1000(DEGREES)K and pressures between 0.025 and 0.25 torr (3.3235 to 33.235 Nm('-2)). Geometry dependence shows that the permeation is not inversely proportional to the log of radius ratio alone. J(,t), the rate of permeation, is empirically expressed as (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) The temperature dependence of the permeability, (phi), is given by (phi) = (phi)(,0) exp (-Q(,p)/RT) where (phi)(,0) = 2.86 x 10('6) (cm('3) (.) s('-1) (.) cm('-1) (.) (Nm('-2))('-0.8)) Q(,p) = (230,560 (+OR-) 12,160) (J (.) mole('-1)) The pressure dependence coefficient of 0.8 suggests that the permeation is controlled by surface reactions as well as lattice diffusion. These observations are confirmed from an analysis of lag-time diffusion data. Diffusivity calculated from an expression corresponding to output surface reaction control namely (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) gives the best fit with previously reported data. The diffusivity can be expressed as (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)
Subject Area
Metallurgy
Recommended Citation
GOKHALE, ABHAY ANANT, "GAS PHASE HYDROGEN TRANSPORT IN ZIRCONIUM" (1981). ETD collection for University of Nebraska-Lincoln. AAI8201035.
https://digitalcommons.unl.edu/dissertations/AAI8201035