GLOW-DISCHARGE ENHANCED PERMEATION OF OXYGEN THROUGH SILVER

The permeation of oxygen through Ag0.05Zr over the temperature range o f 300-650-degrees-C under glow-discharge conditions has been studied a nd compared to the permeation of thermally dissociated molecular oxyge n. A low-energy dc glow-discharge in O2 has been employed which produc ed approximately 10% atoms. The permeation rate during the glow discha rge was found to be much higher (a factor of approximately 10) than wi thout the glow discharge. The small fraction of oxygen atoms generated appears to dominate the permeation because of much higher solution pr obabilities. Below 500-degrees-C, the activation energy for the permea tion with glow discharge was found to be 15.5 kcal/mol compared to 22. 0 kcal/mol without glow discharge (molecular oxygen). Above 500-degree s-C, the enhanced permeation with glow discharge gradually diminishes with increasing temperature and approaches that observed without the g low discharge at high temperature; the reason for this is primarily be cause of the thermal instability of the supersaturated high-pressure i nterface where atoms recombine and desorb back into the gas phase.