MACOR(R) Feedthroughs

Providing excellent electrical properties and easily machined, our MACOR(R) Machinable Glass Ceramic (MGC) is frequently used to create hermetic seals and electrically insulating feedthroughs.

MACOR(R) machinable glass ceramic offers exceptional electrical properties and as such it has become the natural choice within electrical insulation applications. We often utilise conductive materials through our MACOR(R) machinable glass ceramic requiring our MACOR(R) MCG feedthroughs to be sealed without sacrificing strength, hermeticity and high use temperature.

Whilst there are many sealing materials, we employ a range of sealing glasses to ensure that desirable properties are achieved without compromising effectiveness.

Sealing Glasses

Ferro Code1 Firing Cycle2 Continuous use temperature (°C) Coefficient of Thermal Expansion
7555* 450°C-20 min. 300 88.5 x 10-7/°C
7570* 470°C-30 min. 330 84 x 10-7/°C
7572 450°C-60 min. 425 95 x 10-7/°C
7575 450°C-60 min. 425 89 x 10-7/°C
1. Ferro Corporation, PO Box 6550, 4150 E. 56th Street, Cleveland OH, 44101. Tel. (216) 641-8585, ext. 7426, Fax (412) 641-8857.
2. These are idealised conditions. Heating and cooling rates and soak times are dependent on the size and geometry of the parts. The time is the hold at the corresponding temperature.
3. Vitreous solder glass.

MACOR(R) machinable glass ceramic (corning code 9658) can be used to hermetically seal glass, ceramic or metal due to its high glass content.

This glass content combined with a high coefficient of thermal expansion makes it possible to seal MACOR(R) to a wide range of different metals and glasses.

Using solder glass frit it is possible to achieve vacuum tight seals which can be used at high temperatures. MACOR(R) machinable glass ceramic and solder glass frit can be sealed to the following:


  • Platinum
  • Titanium
  • Sealmet
  • Dumet
  • Chrome-iron stainless
  • 52% nickel alloys
  • Sylvania #4


  • Fosterite

To find out more about our MACOR(R) product range, or to place an order, please contact us.

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