Study of the outgassing behavior of SnO 2:F films on glass in vacuum under external energy excitation

Abstract

Vacuum glazing consists of an evacuated space between two sheets of glass. Vacuum glazing has a large effect on energy savings in houses and buildings. Vacuum glazing can achieve higher insulating performance than conventional insulated glazing. Nippon Sheet Glass has successfully developed conventional vacuum glazing. In this study we investigated an advanced form of vacuum glazing. Its thermal insulation ability is equivalent to 100 mm thick glass wool thermal insulation. This vacuum glazing contained a SnO 2:F low emissivity surface. The influence of the residual gas in a vacuum space on heat flow is important to performance. For long-term thermal stability, it is very important to maintain vacuum stability. To understand this better, we studied the behavior of outgassing from the inside glass surfaces exposed to an external energy source. We have studied the behavior of outgassing from a glass surface using a Nd:YAG laser (operated at 355 nm wavelength) and Q-mass spectroscopy in vacuum. As a result, we identified both carbon compounds and water as outgassing products. The behavior of the carbon compound (mass number 44) was different from water (mass number 18). We investigated the relationship between outgassing behavior, baking temperature and laser intensity. Surface analysis was performed on the glass surface. As a result of XPS analysis on the glass surface, the amount of carbon compound observed was a function of baking temperature. SIMS showed that the amount of adsorbed carbon in the SnO 2:F film was reduced with the increasing baking temperature, and with UV irradiation. For samples baked at 400 °C in vacuum, the carbon adsorption in SnO 2:F film does not show significant difference between before and after UV irradiation.