The document discusses several coating techniques used in ceramic science: - Dip coating involves withdrawing an object from a liquid coating at a controlled speed, with coating thickness calculated by the Landau-Levich equation. Gelation then occurs through solvent evaporation and sol destabilization. - Capillary coating combines the advantages of dip coating with utilizing all the coating liquid. - Spin coating involves spinning a substrate to spread a liquid coating through centrifugal force, with final thickness determined by processing parameters in a semi-empirical formula. - Compressive stress coatings through densified ceramic or glass coatings below the substrate glass transition temperature can improve glass strength by factors of 4.

1. Ceramic science and
Dip coating techniques
If the withdrawal speed is chosen such that the sheer rates keep the system
in the Newtonian regime, the coating thickness can be calculated by the
Landau-Levich equation using:
h = coating thickness h = viscosity
gLV
= liquid-vapour surface tension r = density
g = gravity

2. Ceramic science and
Dip coating
Gelation process during dip coating process, obtained by
evaporationof the solvent and subsequent destabilization of the sol

3. Ceramic science and
Capillary coating
• Capillary or laminar flow coating process has been developed by Floch and
CONVAC Co. which combines the high optical quality of the dip coating
process with the advantage that all the coating liquid can be exploited. In
figure 7 the capillary coating process is shown schematically.

4. Ceramic science and
Spin coating
the substrate spins around an axis which should be perpendicular to the
coating area.
The spin-on process has been developed for the so-called spin-on glasses
in microelectronics and substrates with a rotational symmetry, e.g. optical
lenses or eye glass lenses.
final thickness of a spin coated layer on the processing and materials
parameters like angular velocity, viscosity and solvent evaporation rate by
the semi-empirical formula

5. Ceramic science and
Electrochromic cell

6. Ceramic science and
Hydrolysis and polycondensation

7. Ceramic science and
Un vetro antiriflesso attraverso speciali
trattamenti superficiali permette di ridurre
fino a dieci volte la quantità di luce
riflessa
Uncoated
side
AR
Coated Il processo sviluppato è stato
industrializzato e sta per entrare in
produzione
Uncoated
side
AR
Coated

8. Ceramic science and
Glass Strength improvement
Compressive stress coatings can be obtained by densifying ceramic or
glass coating systems, having a lower thermal coefficient of expansion than
the substrate glass and at the same time can be densified below the Tg
of
glass.
So it has been shown that borosillicate sol-gel coatings after densification
can improve the bending strength of float glass by the factor of 4.
Inorganic-organic composite coatings also show that the strength of glass
bottles can be improved substantially.