SCHOTT North America

Solder Glasses

Solder glasses, also referred to as frit glasses, are special glasses with a particularly low softening point (below 550°C). They are used to join glass to other glasses, ceramics, or metals without thermally damaging the materials to be joined. To ensure stress-free sealing, the coefficient of thermal expansion (CTE) needs to be closely matched to the sealing partners.

Product Description

Three kinds of solder glasses can be distinguished according to their behavior during the soldering process: Vitreous solder glasses, devitrifying solder glasses, and composite solder glasses.

Vitreous solder glasses preserve their material properties during soldering and remain in the so-called “glassy” state. When reheated, they show the same softening behavior as prior to the sealing process.

Devitrifying solder glasses crystallize at least partially during the sealing process. Since this results in an increase of softening temperature, they are especially used in applications with high operating temperatures. The crystallization may lead to a change of CTE.

Composite solder glasses were developed to achieve a very low CTE while assuring low soldering temperatures at the same time. This is done by adding inert (non-reactive) fillers with low or negative coefficients of thermal expansion.

Product Advantages

Full range of glass types for different material combinations and temperatures profiles
Lead-free solutions for all major applications
Custom formulation of glass type and grain size upon request
Full support from sample quantities to mass production

Applications

Solder glasses can be used for low temperature joints of different materials in various fields, for example:

Opto-Electronic Packaging (Solder Caps, Lens Caps)
Solid Oxide Fuel Cells (SOFC)
MEMS Packaging
Sealing of Display Devices

Technology

Glass powders are manufactured in two steps:

The raw glass is first melted in specially designed aggregates

The glass ribbons are ground into fine powders of different grain sizes.

For composite solder glasses, an additional mixing step with inert fillers follows.

Features / Specifications

The choice of solder glass for joining different materials is dependent on four major aspects:

Desired soldering temperature
Thermal expansion of the materials to be joined
Operation temperature of the final application
Chemical behavior

Please refer to the following table for details on some standard SCHOTT solder glass types:

All soldering glasses are supplied as glass powder and are available in different grain sizes.

Forms of Supply and Product Packaging

Our standard packaging consists of sealed plastic bottles. For alternative packaging solutions please contact us.

Quality Assurance

Generally, all of our products are RoHS-compliant. For details on individual glasses, please contact us.

For more information on the different quality assurance programs, please refer to our quality assurance processes .

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Contact

Electronic Packaging
SCHOTT North America, Inc.

122 Charlton Street
Southbridge, MA 01550
USA

+1 (508) 765-3370

+1 (508) 765-3377

E-mail

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