Specialty Seals

Producing Assemblies for Special Applications Design


Besides designing and manufacturing high-volume hermetic seals, we can also produce assemblies for special applications.

Applications


  • Capacitors
  • Filters
  • Transformers
  • Microwave tubes
  • Nuclear reactors
  • Space probe devices

Materials


  • High Alumina (insulator)
  • Metal Components
    • OFHC or Te Copper
    • Grade A nickel
    • Low carbon steel
    • Ni-Fe alloy
    • Others required for special applications

Characteristics


  • Vacuum-tight
  • High chemical stability
  • High abrasion resistance
  • High mechanical strength
  • Pressures over 10,000 PSI
  • High temperature usage
  • Low dielectric loss

Physical

  #9095  #9297 
Tensile Strength PSI   18,500  28,500
Compression Strength PSI  280,000  350,000
Modulus of Elasticity PSI
 42.45 x 106 46.09 x 106 
Flexural Strength PSI 46,500 49,500
Impact Resistance, Charpy
6.5-6.8 7.0-7.6
Specific Gravity, Bulk
3.58 3.72
Thermal Conductivity - cal/cm2/cm/25°C
.03-.05
.04-.055
Hardness, MOHS Scale
9 +
9 +
Color
Off-White
Pink
Water Absorption
0 0
Porosity, Helium Mass Spectrometer
Vacuum Tight
Vacuum Tight
Firing Temperature °C
1675
1675
Coefficient of Thermal Expansion > 25-700°C, cm/cm/°C
7.8 x 106
7.9 x 106

Electrical

Dielectric Strength V/mil  1/4" Thick 220  230
Dielectric Constant  106
9.25  9.60
K @25°C
 108 9.25 9.60

 1010
9.15 9.36
Dielectric Loss Factor 25°C 105 .0007 <.0001

 106 .0006 .0005

 107
<.0001
.0004

 108
<.0001
.0004

 109
.0006
.0004

 1010
.001
.0015
Volume Resistivity Ohms/cm3
250°C
6.00 x 1013
2.00 x 1014

500°C
 6.00 x 1010
 1.2 x 1010 

Typical Composition

 

Composition, Alumina Content, Nominally  AL203 - 92% AL203 - 92%

 Si02 - Balance  Si02 - Balance

 Mg0 - Balance Mg0 - Balance 

Ca0 - Balance Ca0 - Balance
    Cr203 - Balance

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