Sealing and Solder Glass
Sealing glasses help create powerful bonds in high-temperature scenarios and corrosive systems, such as fuel cells and batteries. Solder glasses achieve excellent sealing at lower temperatures without thermal damage to partner materials.
With a typical processing temperature of 800-1000°C, sealing glasses are used to create hermetic, highly insulating electrical seals between different materials such as metal, ceramics, or glasses. SCHOTT’s diverse range of standard and custom sealing glasses features a comprehensive variety of coefficients of thermal expansion (CTE). We are able to perfectly match the coefficient of materials that the glass type is being sealed with. SCHOTT Sealing Glasses are available as powders or sintered preforms.
- Complete technical support from sample quantities to mass production using decades of experience in glass-to-metal sealing.
- Lead-free solutions for virtually all possible applications.
- Sodium-resistant glass handles highly corrosive processes.
- Glass-to-metal seals
- Solid oxide fuel cells (SOFC) and electrolyzer cells (SOEC)
- Hydrogen generation and fuel cells
- Flash lights
- High-temperature sensor applications
- Molten sodium batteries (Na/S, Na/NiCl)
Thanks to a particularly low softening point (below 550°C), solder glasses (also referred to as frit glasses) allow the joining of glass to other glasses, ceramics, or metals without thermally damaging the materials. To enable stress-free sealing, the coefficient of thermal expansion (CTE) needs to be closely matched to the sealing partners. SCHOTT Solder Glasses are available as powders or sintered preforms.
- Full range of glass types for different material combinations and temperature profiles.
- Lead-free solutions for all major applications.
- Custom formulation of glass type and grain size upon request.
- Opto-electronic packaging (solder caps, lens caps)
- MEMS packaging
- Sealing of display devices
TYPES OF SOLDER GLASSES
- Vitreous glasses: able to preserve their material properties during the soldering process, remaining in a ‘glassy’ state.
- Devitrifying glasses: partially crystallize while sealing, which raises their softening temperature.
- Composite glasses: maintain a very low coefficient of thermal expansion, while enabling low soldering temperatures.
Granulates and Preforms
SCHOTT also processes sealing and solder glasses down into granulates and preforms. The granulates are agglomerates of glass powder particles, which are held in shape by an organic binder, and provide the basis for the manufacture of sintered preforms used for hermetic glass-to-metal seals and other electronics components.
The preforms are pressed and sintered glass pearls, discs or rods which, for example, are used as spacers. Preforms come in customized geometric shapes and sizes, with diameters ranging from less than one millimeter to several centimeters. SCHOTT also ensures tightly controlled tolerances for preform weight and shape.
- Preforms are ideal for hermetic glass-to-metal seals.
- Available in standard or customized geometric shapes and sizes.
- Closely controlled tolerances for preform weight and shape.