HERMETIC SEALS & FEEDTHROUGHS
Complete Hermetics formulates a multitude of Glass/Ceramics to Metal seal materials successfully for various hermetic
seal applications.
Complete Hermetics is dedicated to customer service. Our engineers will help design and build your hermetic application, whether it is a 5 piece small run or 50,000 piece mass production.
Ceramic to Metal Seal & Feedthroughs
Ceramic Materials Include:
- Aluminum Oxide (Al2O3) at 99.5%
- Aluminum Nitride (AlN)
- Silicon Carbide (SiC)
- Boron Carbide (B4C)
- Silicon Nitride (Si3N4
- Zirconium Oxide (ZrO2)
- Beryllium Oxide (BeO)
- Sialons, YAG, YSZ, etc.
Metal/Alloys Materials Include:
- NiFe Alloys & NiFeCO(Kovar)
- 300 & 400 Series SST
- Molybdenum, Niobium, Tungsten
- Aluminum Silicon Carbide (AlSiC)
- Cu and Cu Alloys
- Nickel & Alloys (Inconel)
- 42, 46, 49 Alloys
- Titanium
Glass to Metal Seals & Feedthroughts
Complete Hermetics provides commercial and in house custom seals on compression and match sealing glasses
commonly used in electronic packages and feedthroughs. Typically glass to metal seals
are divided into: Compression
Seals and Matched Seals.
Compression Seals
Compression Seals: When the CTE (Coefficient of thermal expansion) of the header body or housing greatly exceeds
that of the glass or electrodes, the outer housing components shrink and
mechanically compresses against the glass
to form a compression seal. Steel and Alloy 52 is a common combination of materials to form a compression seal.
- Body Materials: Cold rolled steels, Stainless steel, Inconel, etc.
- Glass Materials: Corning 9010/9013 (Alkali Barium), Soda lime, Lead silicate, etc.
- Electrodes Material: Alloy 52, Copper Cored 52 Alloy, Alloy 42, etc.
Typically Compression Seals withstand temperatures ranging from -250°C to 400°C. Allowable operating temperatures
would be from -60°C to 200°C under thermal cycling and shock.
Matched Seals
Matched Seals: When the CTE (Coefficient of thermal expansion) of the body or housing material matches the CTE of the
glass or electrode material a matched seal is formed. The hermetic seal is
made by forming a bond through wetting and chemical reactions between the glass and metal. Kovar is the most commonly used material for matched seals.
- Body Material: Kovar, Alloy 42, Tungsten, Molybdneum
- Glass Material: Corning 7056 (Alkali Borosilicate)
- Electrodes Material: Kovar, Alloy 42, Tungsten, Molybdneum
Typically Matched Seals maximum allowed temperature is limited by the glass material strain point.
Application
Glass Seals are effective in sealing hermetically during severe changes in temperature, pressure, and humidity compared
to o-rings or epoxy seals.
The highest performance electric seal systems employ ceramics for exceptional hermeticity, integrity, cycling, mechanical
shock, and corrosion. However ceramic materials require more complex
manufacturing processes and engineering costs.
Glass Seals are a cost effective hermetic seal solution and employed on broader industrial applications.
Hermetic Seal Properties
- Insulation Resistance: Typically exceeds 1 Gigaohms at 100 VDC
- Dielectric: Dielectric constants of some commonly used glass: Corning 9010– 6.3; 7052–4.9; 707– 4.1.
- Mechanical Strength: up to 20,000 PSI with proper design and processing.
- Hermeticity: up to 1x10-9 atm cc/sec Helium.
Partial Customer List:
