Oxygen isotope exchange reaction in diffusion coefficient measurements using gas phase analysis

Mixture of O-18(2) and O-16(2) gases was used as a tracer in oxygen diffusion experiment of solid (Y-TZP) in which the concentration of O-18 in the gas phase was determined directly by a mass spectrometer. If a simple mixture of these gases was used, the formation reaction of (OO)-O-18-O-16 gas had an effect on the concentration determination, especially when the diffusion time was short, In order to go around the effect, it was essential to use a gas mixture in which oxygen isotope exchange reaction (formation reaction of (OO)-O-18-O-16 gas) was in equilibrium at the diffusion temperature.