Applications of surface analytical techniques for study of the interactions between mercury and fluorescent lamp materials

Several surface analytical techniques, including electron spectroscopy for chemical analysis (ESCA) (X-ray photoelectron spectroscopy) and sputtered neutral mass spectrometry (SNMS), were used to study the interaction between Hg and other components of fluorescent lamps, a very critical issue in lighting industries. Active sites, responsible for Hg interaction/deposition, can be successfully identified by comparing the x-y distribution (obtained by ESCA mapping) and depth distribution (available through SNMS) of respective lamp components with that of Hg. A correlation in both depth and x-y distribution is strong evidence of site preference for Hg interaction/deposition. A burial mechanism is, however, proposed when only depth distribution, not x-y, is correlated. Other modes of ESCA (high resolution, angle-resolved, etc.) were also helpful. Information about the valence states of the interacted Hg species would help to define the nature of the interaction.