Hydrogen Permeability through n-type Cr₂O₃ Scale at 1273 K under the Oxygen Activities of 1.6 × 10^–18 – 1.0 × 10^–16

抄録

The effect of dissolution of hydrogen on the defect structure of Cr₂O₃ was studied. The hydrogen flux and permeability through Cr₂O₃ scale were measured at 1273 K in the oxygen activities of 1.6 × 10^–18 – 1.0 × 10^–16. The oxygen activities on the both sides of the sample were controlled by fixing the H₂/CO₂ and CO/CO₂ ratios to measure the hydrogen permeability without oxygen activity gradient through the sample. The measured hydrogen flux and permeability was proportional to a_H2^1/2 and a_O2^–1/8 respectively. The activity dependences indicate that dissolved hydrogen is the neutral hydrogen at oxygen site as a minor defect and does not affect the oxidation behavior of chromia-forming alloys.