SCHOTT Technical Glasses

61
and unique solution, particularly in high temperature environments.
The material is manufactured e.g. in sheet form and can be
further processed by using a wide variety of technologies.
The following different features are in principal producible –
all others upon request:
• Cut to size panels, flat, and surface smooth
• Ground in random shapes and with inner cuttings
• Ground, polished, with bevelled edges or drilled holes
Nextrema is a type of glass-ceramic consisting of a crystalline
and a residual glassy phase. The glass is obtained e.g.
by a rolling process and is subsequently subjected to a heat
treatment as described in the introduction before. This is
called ceramization which transforms, in a controlled manner,
the glass almost completely into both a fine grained
crystalline phase and a residual glassy phase. Mainly different
ceramization processes determine both the features and
the types of Nextrema available. Therefore no one type
of NEXTREMA is like another. The approach is to design
glass-ceramic that corresponds to the individual and specific
requirements as precisely as possible. Each product feature
individually or particularly combined can lead to new technical
developments and fields of application.
The ceramic types are available in 4 types, generally:
I. transparent
II. tinted
III. translucent (white colored)
IV. opaque (white or grey colored)
4. Smooth, non-porous surface and process inertness
NEXTREMA is process inert. Even under extreme conditions,
the material will not have negative interactions
with the process environment. There are no interfering
process factors such as gas emissions from organic components.
5. Wide transmittance spectrum means high transmittance
for wavelengths covering the visible and infrared range.
6. Very low transmittance for ultraviolet range.
7. High dimensional and shape stability of objects made
from these ceramic materials.
These outstanding technical properties guarantee suitability
for a wide range of technical applications, e.g.
• Solar processing
• LCD/OLED processing
• Heating/Lighting (e.g sauna, space heating, IR-heating/
drying)
• Food processing (e.g. grills, toasters, outdoor fireplaces,
microwave applications)
• Setters for firing electronic components
• Carrier plates in CVD-furnaces
• Cover panels for heating elements and burners
• Cover panels for projectors/beamers/photocopiers
• Windows for combustion furnaces
• Interior panels of oven doors
• Carrier/protection plates for food processing industries
• Linings for furnaces
• Ceramic carrier plates for sputtering and solar production
The technical basis of NEXTREMA covering a family of
high-performance glass-ceramics is formed by main seven
product features.
1. Near zero thermal expansion and thereby with excellent
thermal strength, Nextrema glass-ceramic consists of a
material that has an intelligent microstructure specifically
designed to achieve very low thermal expansion and
excellent heat resistance.
2. Robustness at high operating temperatures (up to
950 C °/1742 °F) and high thermal shock resistance (up to
800 C °/1472 °F).
3. High chemical resistance like multiple resistance to acids
and bases and impermeability with gas.
Nextrema high-performance glass-ceramic
10