Ceramic-to-Metal Seals

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

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

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).

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
Material:	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

Designs:	Designed and manufactured to buyer specifications and engineering drawing. Developed Specialty Seal Group engineers from customer’s general description.
Materials:	Insulator-Glazed Ceramic 92-96% Al₂O₃ (white or pink) Metal Components OFHC Copper Grade A Nickel Nickel-Iron Alloy Low carbon Steel Monel Bronze Kovar Brass Other metals as required for special application
Applications:	Aerospace Medical Equipment Aviation Defense Industries Automotive Defense Industries
Special Characteristics:	Vacuum Tight High Chemical Stability High Abrasion Resistance High Mechanical Strength Pressure Over 10,000 PSI High Temperature Low Dielectric
Special Characteristics:	Tin Nickel Gold Hot Solder Sulfamate Electroless Watts Electrolytic Electroless

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.

Consult the factory for installation criteria for all Specialty Seal Group hermetic seals.