THERMAL OUTGASSING STUDY ON ALUMINUM SURFACES

Thermal outgassing rates of aluminum chambers vented to nitrogen atmospheres with different humidity were measured. Both desorption and diffusion phenomena were observed in the outgassing rate curves, the lower the humidity the clearer the diffusion effect. The build-up curves of water vapor were compared for different ventings, the build-up rate being insignificant for the case of venting with dryer nitrogen gas. An adsorption and desorption process of water molecules on aluminum surfaces is described and discussed.