CORNING® 7056 KOVAR SEALING

Schott® borosilicate glass 7056 was widely used as a Kovar Sealing glass and/or Hermetical Sealing glass.¬†This glass has been discontinued and is out of melt. This borosilicate glass was replaced with Corning® 7720 Nonex Tungsten Sealing glass which also has been discontinued and has now been replaced by Schott® 8250 Kovar Sealing glass. You can also view Corning® 7052 Kovar Sealing glass datasheet.

Kovar Sealing Glass: Corning® 7056
Glass Code: Corning®
7056
Type
Alkali Borosilicate
Color
Clear
Principal Use
Electronic
Mechanical
Metric English
Density
2.29g/cm3
143 lb/ft3
Young's Modulus
6.4 x 103 kg/mm2
9.2 x 106 psi
Poisson's Ratio
0.21
Shear Modulus
2.7 x 103 kg/mm2
3.8 x 106 psi
Viscosity
Metric
English
Working Point (104Poise)
1058°C
1936°F
Softening Point (107.6 Poise)
718°C
1324°F
Annealing Point (1013 Poise)
512°C
954°F
Strain Point (1014 Poise)
472°C
882°F
Thermal Metric English

Coefficient of Expansion (0 - 300°C)

(25°C to set point 679°C)

51.5 x 10-7/°C
28.5 x 10-7/°F
54.5 x 10-7/°C
30.0 x 10-7/°F
Optical Metric English
Refractive Index (589.3nm)
1.487
Birefringence Constant 300nm/cm/kg/mm2
Electrical
Metric
English
Log10 Volume Resistivity @ 250°C 10.3 ohm-cm
Log10 Volume Resistivity @ 350°C
8.4 ohm-cm
Dielectric Constant @ 20°C, 1MHz 5.7
Loss Tangent @ 20°C, 1MHz
0.27%

 

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