|Thin, transparent coatings of amorphous Si02 and Al20 3 were deposited
on soda lime glass substrates by the dip technique, using organometallic
precursor sols. The water content of the sol was found to
influence its wetting behaviour, low values of H20: Si(OC2H6),
being preferred for Si02 and high values of H20: AI(OC,H9B)3 for
Al20a coatings of sufficient uniformity and clarity. Expulsion of
volatiles and polycondensation of the coated material were allowed
to take place via (i) an initial baking step at 90°-l00°C and (ii) a
final heating step at 350°-500°C according to the sol composition.
The procedure yielded homogeneous, highly transparent coatings,
showing 84-93% transmission of the visible runge of wavelengths.