Figure 6. XPS spectra (Ag 3d core-level) of Ag standards, AgZ, Ag0Z, and aged Ag0Z in dry air and humid air at 150 oC for 2 months; D-2m-Ag0Z is for the aged Ag0Z in dry air for 2 months and H-2m-Ag0Z is for the aged Ag0Z in humid air for 2 months.