Abstract
Corrosion resistant pure iron thin films were formed on silicon and silica glass substrates through 157-
nm fluorine (F2) laser-induced photochemical surface modification. When a silica glass substrate was
used, the thickness of the Fe3O4 modified layer remarkably increased from 2 to 8 nm in addition to a
change in the surface color and surface swelling of the F2 laser-irradiated sample. We discussed why the
thickness of the Fe3O4 modified layer increased, the surface color changed, and the surface swelled in
terms of the difference of thermal conductivity between silicon and silica glass. We also examined the
dependence of the thickness of pure iron thin films on the thickness of the Fe3O4 modified layer and the
surface color change. The F2 laser-irradiated pure iron on silica glass successfully showed higher
corrosion resistance to a 3 wt% NaCl aqueous solution; no rust was observed at 96 h and over, compared
with the case in silicon substrate for 48 h.
