Hydrogen Permeability of Sintered Aluminum Oxide

Abstract

Hydrogen permeability of high‐density, high‐purity sintered alumina tubes was measures is a function of temperature and pressure using tritium as a tracer. The permeability, ø, at 1200° to 1450°C and hydrogen partial pressure between 2 and 50 kPa is: φ(H atoms cm cm −2 s −1 kPa −0.43 ) = exp(48.95±0.61) exp[−318.2±18.8 kJ(g·atom) −1 (RT) −1 ] Diffusion coefficients and solubility values deduced from the permeation experiments are consistent with earlier independent measurements. No accelerated permeation due to micro‐structural defects or changes during the experiments was observed. Comparison of hydrogen permeability of alumina with the values observed for metals shows that alumina may be a suitable coating material for use as a hydrogen permeation barrier.