Hermetic Seals (Glass to Metal Seals)

Since 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 of the available combinations are shown in the table below.

Typical compression seals will withstand extreme temperatures, in some cases -454o F (-270o C) to 842o F (450o 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:

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

Material	Compression Seal	Matched Seal
Header / Body	● Cold Rolled Steel, Inconel, Stainless Steel	● Kovar, Tungsten, Molybdenum
Electrodes	● 52 Alloy, Copper Cored 52 Alloy, 42 Alloy, 42-6 Alloy	● Kovar, Tungsten, Molybdenum
Glass	● Alkali Barium, Lead Silicate, Potash Lead, Soda Lime	● Borosilicate (Alkali, Barium, Soda, Potash)

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

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地址：台北市长安东路二段171号4楼之3

Address：4F-3. No.171. Sec.2. Chang An.E.Rd. Taipei. Taiwan. R.O.C.

电话：(02)27111093~5

Tel：886-2-27111093~5

传真：(02)27310902, 27764624

Fax：886-2-27310902,27764624

Email:jinzon@ms2.hinet.net