General Description Kovar is a nominal 29%Ni-17%Co-54%Fe alloy that is a well-known
glass-sealing alloy suitable for sealing to hard glasses. Kovar has
a nominal expansion coefficient of approximately 5 ppm/°C and
inflection temperature of ~450 °C (840 °F). Kovar (ASTM F15) has been used for making hermetic seals with the
harder Pyrex glasses and ceramic materials. This alloy has found
wide application in power tubes, microwave tubes, transistors, and
diodes. In integrated circuits, it has been used for the flat pack
and the dual-in-line package. Chemical Composition Grade | C% | P% | S% | Mn% | Si% | Cu% | Cr% | Mo% | Ni% | Co% | Fe% | Kovar | Max 0.03 | Max 0.020 | Max 0.020 | Max 0.50 | Max 0.30 | Max 0.20 | Max 0.20 | Max 0.20 | 28.5-29.5 | 16.8-17.8 | Bal. |
Specifications Grade | UNS | Werkstoff Nr. | ASTM | Kovar | K94610 | 1.3981 | F15 | |
Physical Properties Grade | Density | Melting Point | Kovar | 8.17 g/cm3 | 1449°C |
Mechanical Properties Grade | Tensile Strength N/mm² | Soft | 1/4 Hard | 1/2 Hard | 3/4 Hard | Full Hard | Kovar Strip | <570 | 520-630 | 590-700 | 600-770 | >700 | Kovar Wire | <585 | 585-725 | 655-795 | 725-860 | >860 |
Coefficient of Expansion Alloy | Linear Coefficient of Thermal Expansion ā,10-6/℃ | 20-200℃ | 20-300℃ | 20-400℃ | 20-450℃ | 20-500℃ | 20-600℃ | 20-700℃ | 20-800℃ | Kovar | 5.9 | 5.3 | 5.1 | 5.3 | 6.2 | 7.8 | 9.2 | 10.2 |
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