Kovar controlled expansion glass ceramic sealing seals alloy rod round bar sheet plate strip

Kovar® Alloy Physical Properties

(Also known as ASTM F15, NILO® K, Pernifer® 2918, Rodar®, and Dilvar® P1)

Density lb/cu in 0.302
Specific Gravity   8.36
Curie Temp °F 815
  °C 435
Melting Point °F 2640
  °C 1449
Electrical Resistivity Micro-ohm-cm 40
  Micro-ohm-cm 294
Thermal Conductivity W/cm °C 0.17
  BTU-in/sq. ft-hr- 120
Specific Heat Cal/g- °C 0.11
  BTU/lbm- °F 0.11
Thermal Expansion ppm/°F (75°F to 842°F) 2.9
  ppm/°C (25°C to 450°F) 5.3

Kovar® Alloy Mechanical Properties

Tensile Strength ksi 75
  MPa 518
Yield Strength ksi 40
  MPa 276
Elongation % in 2 in. 30
Typical Hardness Ann. Rockwell HRB 80
Modulus of Elasticity Mpsi 30
  kMPa 207

Kovar® Alloy Chemistry

maximum % unless noted
Iron Bal
Nominal Nickel 29
Nominal Cobalt 17
Carbon 0.02
Silicon 0.20
Sulfur --
Chromium 0.20

Kovar® Alloy Linear Coefficient of Thermal Expansion

Degree C   Degree C
30-100 5.8 30-450 5.1 - 5.5
30-150 5.6 30-475 --
30-200 5.4 30-500 6.1
30-250 5.3 30-525 --
30-300 5.1 30-550 6.8
30-325 -- 30-600 7.5
30-350 4.9 30-700 8.7
30-375 -- 30-800 10.3
30-400 4.6 - 5.2 30-900 10.8
30-425 -- 30-1000 11.7
Underscored face values are the limits specified in MIL-l-23011C