Ceramic-to-Metal

Ceramic-to-Metal End Seals Give Top Performance in Harsh Industrial Environments


Specialty Seal Group (SSG) offers ceramic-to-metal seals for a wide range of uses...

Single & Dual-Lead Seals


Typical Applications
  • Industrial Heaters
  • Terminating Power Cables
  • Isolating Other High Heat or Power Sources
Functions
  • Provide vacuum-tight insulated feed thru termination for heating elements or power cables
  • Protect heating element from attack by oils, grease moisture, and toxic fumes
Materials
  • Insulator – Glazed Ceramic 92-96% Al2O3 (white or pink)
  • Threaded Stud - Monel, Steel, Inconel or Nickel
  • Tube - Nickel
  • Cap-Nickel
  • Weld Sheath - Nickel
  • Consult Specialty Seal Group for optional Sleeve Adaptors suitable for wedding (stainless steel or alternative materials)
Special Characteristics
  • Rugged End Seal Construction withstands normal torch assembly and retains hermeticity in spite of extreme operating temperatures, vibration, shock, and corrosive atmospheres
  • Assembled to heater by torch or induction brazing. the most common braze material for customer assembly is ASTM # Bag-1 (MP-1125/1145 Degree F.) Braze materials with melting points up to 1500 Degree F have been used successfully
  • Shipments from stock or quick deliveries from production (in house components)
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High-Temperature Feed thru Terminals


Designs
  • Feedthrus or Pin Seals are custom made to specifications that determined by the electrical, temperature, and environmental condition requirements.
  • The parts illustrated on this page are a cross section of Feedthrus/Pin --Seals manufactured at Specialty Seals Group
  • Standard parts are available
Applications
  • Aerospace
  • Defense Industries
  • Aviation
  • Medical Equipment
  • Industrial Application
  • Nuclear Equipment
Functions
  • Insulated feedthru for electrical connection
  • Compatible for vacuum technology
Materials
  • Insulator-Glazed Ceramic 92-96% Al2O3 (white or pink)
  • Feedthru Tube - Nickel, Kovar, Copper
  • Weld Shealth/Flange-Nickel, Kovar, 304 Stainless Steel
Special Characteristics
  • High Abrasion Resistance
  • High Mechanical Strength
  • Pressures over 10,000 PSI
  • High Temperature Usage
  • Low Dielectric Loss
  • Mass Spectrometer Leak Tested
  • High Chemical Stability
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Specialty Seals


Designs
  • Feedthrus or Pin Seals are custom made to specifications that determined by the electrical, temperature, and environmental condition requirements.
  • The parts illustrated on this page are a cross section of Feedthrus/Pin --Seals manufactured at Specialty Seals Group
  • Standard parts are available
Applications
  • Aerospace
  • Defense Industries
  • Aviation
  • Medical Equipment
  • Industrial Application
  • Nuclear Equipment
Functions
  • Insulated feedthru for electrical connection
  • Compatible for vacuum technology
Materials
  • Insulator-Glazed Ceramic 92-96% Al2O3 (white or pink)
  • Feedthru Tube - Nickel, Kovar, Copper
  • Weld Shealth/Flange-Nickel, Kovar, 304 Stainless Steel
Special Characteristics
  • High Abrasion Resistance
  • High Mechanical Strength
  • Pressures over 10,000 PSI
  • High Temperature Usage
  • Low Dielectric Loss
  • Mass Spectrometer Leak Tested
  • High Chemical Stability
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General Ceramic-to-Metal Design Guidelines


  • Place ceramic in compression rather than tension.
  • Maximum solid metal pin diameter is .060" where pin is brazed directly to ceramic ID.
  • Choose a metal such as Kovar with the most closely matched expansion to the ceramic when possible.
  • The metal selected to be bonded to the outside diameter of a ceramic should have a thermal expansion > Al2O3.
  • The outside metal member should be of the thinnest cross-section thickness possible to take up expansion mismatch.
  • The selected metal should be as ductile as the design permit.
  • Service temperature must be considered in allowing of expansion-contraction stresses.
  • When internal conductors > .060" are required, a metal tubing with a .010" wall will yield totakeup expansion mismatch.
  • Avoid butt seals. If impossible, use the thinnest ductile metal available.
  • Step braze subassembly techniques should be considered.
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