Ceramic-to-Metal Seals
Specialty Seal Group offers ceramic-to-metal seals for a wide range of uses.
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.
Single & Dual-Lead Seals
Typical Applications
- Industrial Heaters
- Terminating Power Cables
- Isolating Other High Heat or Power Sources
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)
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)
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
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
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
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
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
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
More Options from Specialty Seal Group
Glass-to-Metal Seals
Glass-to-Metal Sealing Meets Challenges of the Most Demanding Applications. There are two types of glass seals available at Specialty Seal Group: Compression Seals and Matched Seals.
Specialty Seals
Producing Assemblies for Special Applications including capacitors, filters, transformers, microwave tubes, nuclear reactors and space probe devices.
Ceramic Selection
Ceramic-to-Metal End Seals Give Top Performance in Harsh Industrial Environments.