Sealing Glass | Hermetic Glass Seals

Product Description

To manufacture hermetic and highly insulating electrical seals between different materials such as metal or ceramics, the use of sealing glasses is wide spread in the electronics industry. Sealing glasses typically have a processing temperature of 800–1000°C.

Sealing glasses mostly belong to the borosilicate and aluminosilicate glass families.

To manufacture reliable hermetic glass seals, the correct choice of coefficient of thermal expansion (CTE) is a key factor. The applied glass composition depends on the materials, which should be joined, the required temperature profile as well as their CTE. For matched seals, the CTE of the glass is matched as closely as possible to those of the sealing partners. In case of compression seals, a well-defined mismatch of the CTE is used intentionally to compress the sealing materials onto each other.

SCHOTT offers sealing glass for both sealing concepts and a variety of materials ranging from silicon to stainless steel.

SCHOTT provides sealing glasses in the form of fine ground powder, paste, granulate and preforms. 

SCHOTT provides glass and glass-ceramic sealants for technical ceramics in high-temperature applications. Please refer to the download tab for more information.


  • Great scope of different glass types and grain distributions
  • Lead-free solutions for virtually all possible applications
  • Custom formulations upon request
  • Full support from sample quantities to mass production with decades of experience in glass-to-metal sealing technology


  • Glass-to-metal seals
  • Solid oxide fuel cells (SOFC)
  • Flash lights
  • High temperature sensor applications
  • Molten sodium batteries (Na/S, Na/NiCl)

Technical Details


Glass powders are manufactured in two steps:

Features / Specifications

Please refer to the tables below to choose the right sealing glass for a variety of material combinations.
All sorts of sealing glasses are available in a number of different grain sizes. 

Forms of Supply and Product Packaging

Our standard packaging consists of sealed PE-Bags in cardboard drums. For alternative packaging solutions, please contact us.

Sealing glasses for high-temperature applications:
Sealing Partner
SCHOTT Glass Number
CTE* (10-6/K for 20-300oC) 
Tg  (oC)
Sealing temperature (oC)
Maximum operating temperature (oC)
SiC 8253 4.6 785 1320 735
AlN G018-200 4.6 557 665 550
Al2O3 G018-266 6.9 585 770 530
  G018-346 7.3 720 1270 670


685 940


  G018-385 8.4** 992 950 950oC (1000)
ZrO2 G018-339 9.2** 627 990 760**



622 850


*CTE = coefficient of thermal expansion   **p.c. = partially crystalline

SOFC sealing glasses:

Glass No.
α(20-300) [ppm/K]*
Tg [oC]*
Dil. Ew [oC]*
Sealing temperature [oC]
Sealing partners
GM31107 9.8 543 592 3.70 700 Crofer, ITM, StS
G018-281 12.1 639 >850 2.70 1000 CFY
G018-311 9.9 612 686 3.80 850 Crofer, ITM, StS
G018-354 9.2 637 711 3.90 850 Crofer, ITM, StS
G018-381 12.1 652 >850 2.30 950 CFY
G018-385 8.4 992 >1000 3.14 1000 CFY
*partially crystalline


For more information on the different quality assurance programs, please refer to our quality assurance processes.
Exhibitions & Events
Exhibition CIOE - China International Optoelectronic Exposition, Shenzhen, China, 09-01 to 09-03-2021
Exhibition Gastech, Singapore, Singapore, 09-13 to 09-16-2021
Electronic Packaging
SCHOTT North America, Inc.

15 Wells Street
Southbridge, MA 01550
E-Mail to SCHOTT+1 (508) 765-7450
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