If you need hermetic seals for specific applications, the technical information, guidelines and tips throughout the next several pages will help you select seal designs that are most efficient and competitively-priced. These data have been derived from the experiences of Specialty Seal Group engineering and production staff over more than 50 years of service to customers in a wide variety of industries.
After you have worked with us to establish the parameters for your seals, Specialty Seal Group’s state-of-the art capabilities in CAD design, CNC machining, sealing technology, mass spectrometer leak testing, and plating finishes will yield accurate, cost-effective results.
|Tensile Strength PSI||18,500||28,500|
|Compression Strength PSI||280,000||350,000|
|Modulus of Elasticity PSI
||42.45 x 106||46.09 x 106|
|Flexural Strength PSI||46,500||49,500|
|Impact Resistance, Charpy
|Specific Gravity, Bulk
|Thermal Conductivity - cal/cm2/cm/25°C
|Hardness, MOHS Scale
|Porosity, Helium Mass Spectrometer
|Firing Temperature °C
|Coefficient of Thermal Expansion > 25-700°C, cm/cm/°C
||7.8 x 106
||7.9 x 106
|Dielectric Strength V/mil||1/4" Thick||220||230|
|Dielectric Constant|| 106
|Dielectric Loss Factor 25°C||105||.0007||<.0001|
|Volume Resistivity Ohms/cm3
||6.00 x 1013
||2.00 x 1014
|| 6.00 x 1010
||1.2 x 1010|
|Composition, Alumina Content, Nominally||AL203 - 92%||AL203 - 92%|
|Si02 - Balance||Si02 - Balance|
|Mg0 - Balance||Mg0 - Balance|
|Ca0 - Balance||Ca0 - Balance|
|Cr203 - Balance|
NOTE: All data tests completed to ASTM standards. Results are average for specimen tested and should be - but are not guaranteed to be - applicable to parts made of the material.
As a rule, ceramic cost increases as the purity of raw Al2O3 increases. Specialty Seal Group excels at providing the strongest ceramic-to-metal seals and metallized ceramics with the lowest cost per alumina content possible.
Typically, 92-96% of Al2O3 ceramics prepared with Specialty Seal Group’s proprietary metallization process provide high performance where reliability and strength are critical. In addition, Specialty Seal Group ceramics promote increased thermal conductivity, chemical resistance and dielectric strength. H2SO4 and HCl, for examples, will not attack a ceramic, eliminating the probability of corrosion in a number of applications.
Those factors, along with alumina’s high temperature tolerance and high compressive strengths, make it the ceramic material of choice.