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HERMETIC SEALS

Hermetic Seals (Glass to Metal Seals)

Hermetic Seals Main02Since the founding of the Durakool name over 70 years ago, our HermaSeal division has supported our Relay and Switch product line with in-house design and manufacturing of hermetic glass-to-metal seals, feed-throughs and metal-to-metal vacuum brazing. Requirements for unique and intricate seal components, which must withstand extreme challenges, are our speciality. Advanced, characteristics like:

● Ceramic-to-Glass bonding
● Metal-to-Metal brazing
● Glass-to-Metal sealing

Can all be done simultaneously using our proprietary processing. Our in-house capabilities continue to supply various niche applications with this core expertise; HermaSeal is here to support your needs.

HermaSeal is capable of manufacturing transistor packages, quartz crystal packages, housings for photodiodes, hybrid packages, diode housings, battery and power feed-throughs, sensor packages, microwave packages, and many other custom designs.

TYPES OF SEAL AVAILABLE

STANDARD PRODUCT RANGES INCLUDE

● Compression

● TO-Series headers

● Matched

● Diode packages

● Single pin

● Feed-throughs

● Multiple pins

● Flange mounted packages

 

● Sight Seals Etc.









CUSTOM DESIGN

If you require an application specific hermetic seal or combination Glass/Ceramic/Metal assembly, HermaSeal would be pleased to provide engineering support with your design.

APPLICATIONS INCLUDE

TECHNOLOGY ADVANTAGE

● Opto-electronics

● Excellent electrical insulation

● Telecommunications

● High hermeticity

● Automotive Electronics

● Pressure resistance

● Pressure Sensors

● Corrosion resistance

● Battery Terminals

● High operating temperature

 

● Mechanical strength

 

● Solderability

 

● Easy final assembly (i.e. welding or wire bonding)

 

● High reliability















TECHNOLOGY COMPARISON

COMPRESSION SEALS: The coefficient of thermal expansion of the header/seal body greatly exceeds that of both the glass and the electrode(s). The external metal component shrinks to form a compression ring around the glass. Assemblies are available in many combinations of materials, including:

Header/Body:

Electrodes:

Glass:

● Cold Rolled Steel

● 52 Alloy

● Alkali Barium

● Inconel

● Copper Cored 52 Alloy

● Lead Silicate

● Stainless Steel

● 42 Alloy

● Potash Lead

 

● 42-6 Alloy

● Soda Lime









Typical compression seals will withstand extreme temperatures, in some cases -454� F (-270� C) to 842� F (450� C) with no loss in integrity.

MATCHED SEALS: The coefficient of thermal expansion of the metal components and the glass are similar. The hermetic seal is typically made by forming a bond between the glass and the oxide created on the metal components prior to sealing. Assemblies are available in the following combinations of materials:

Header:

Body:

Electrodes:

Glass

● Kovar

● Tungsten

● Molybdenum

● Borosilicate (Alkali, Barium, Soda, Potash)




Matched seals are more susceptible to temperature excursions, and are not recommended for applications exceeding 85� F (-65� C) to 482� F (250� C).

Typical Characteristics offered by our seal assemblies

● Insulation resistance ranges from 1010 to 1012 Ohms.
● Breakdown voltage 40 VAC/55 VDC per radial .001 of glass between header and electrode
● Hermeticity 1.0 x 10-9 1.0 x 10-10Atm cc/sec (mbar l/s) He.

SURFACE FINISH

HermaSeal offer a variety of high quality surface finishes to meet the application requirements. These include but are not limited to:

Material

Advantages

Electroless Ni

● Good corrosion protection
● Good wire bonding
● Good solderability with flux
● Uniform thickness
● Good weldability

Electrolytic Ni 

● Good corrosion protection
● Good solderability
● Excellent pre-plate for Au

Pure Au flash

● Improved solderability
● Protects against tarnish/oxidation

Pure Au

● Good wire bonding
● Excellent solderability without aggressive flux

Hard Au

● Wear resistant protection for contacts, plugs, connectors

Ag � Silver

● Excellent solderability
● High electrical conductivity

Sn � Tin

● Improved corrosion protection
● Very good solderability

Cu � Copper

● Good conductivity
● Excellent pre-plate for Ag

Please contact us with your requirement:~

Company

Contact

Tel. Number

Fax. Number

Web Address

Email Address

Address

Products of Interest

Application

Final Finish

Header Finish

Electrode Material

Seal / Glass Diameter

Header Dimensions

Number of Electrodes

Electrode Diameter

Glass Specification

Special Requirements

Quantity Required

Additional Notes

Willow Technologies Ltd. Unit 3 Borers Yard, Borers Arms Road, Copthorne, West Sussex, RH10 3LH, UK

Tel: +44 (0) 1342 717102, Fax: +44 (0) 1342 717014, Email: sales@willow.co.uk

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