Objective
- Enhancement of fracture strength, s 0 of (thin)
glass sheets through inorganic sol-gel coatings with glass like optical (transparency),
chemical and mechanical (wear resistance) properties
Methods
- Effecting the geometry of the microcracks (reduction of the crack length, by filling out
the crack tips) or building-up of compressive stress upon the glass surface using a
sol-gel coating
- Application by dip or spin-coating
- Densification at 500 °C under air
- Determination of the fracture strength (s 0) and
Weibull modulus (m), using double ring bending (as according to DIN 52292) followed by
Weibull statistical analysis
Results
- Transparent glass like coatings (coating thickness 0.1 - 2 m
m, adjustable)
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- Enhancement of the fracture strength (s 0) from
430 MPa to 1100 MPa (by 150 %) for thin glass (500 µm) and from
120 MPa to 240 MPa (by 100 %) for 2 mm thick float glass
- Enhancement of Weibull modulus (m) from 2 up to 10
- Suppression of stress corrosion; the life time of coated glass in water is higher than
that of un-coated glass in air
Applications
- Covers for the displays
- Covering glass in the photovoltaics
- Laminates (e. g. plastic - glass)
Benefits
- Increasing of the bending strength of glass, which could not be hardened by techniques
from state of the art becuase of by their low thicknesses (< 500 µm) and
their compositions
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Laboratory Technology
