Kovar Sheet

Kovar? is made up of 29% nickel, 17% cobalt, .2% silicon, .3% manganese and 53.5% iron. Kovar? is known for its low coefficient of thermal expansion. Kovar? end uses are usually glass sealing in the electronics industry.

Kovar Sheet

Alloy K / K94610 / ASTM F15 Also known as Kovar and Nilo K**, this alloy contains 29% nickel with a 17% cobalt addition. Its composition is tightly controlled within narrow limits to ensure precise and universal thermal expansion and mechanical characteristics. This helps the material provide high integrity glass-to-metal and ceramic-to-metal seals in applications requiring reliability and resistance to thermal shock. Alloy K is often used for the manufacture of hermetic seals with both the harder Pyrex or borosilicate glasses and alumina-type ceramic materials. It finds extensive application in the production of transistors and diodes for lids and closures in a variety of hybrid electronic circuit packages and also in the manufacture of microwave tubes.

Material : 

Russia USA England Japan Franch Germany
29HK kovar Nilo K KV-1 Dilvar P0 Vacon 12
29HK-B? Rodar
Techallony Glasseal29-17
Teleaseal KV-2
Dilver P1 Silvar

Content Composition %

C P S Mn Si Cu Cr Mo Ni Co Fe
Less than
0.03 0.02 0.02 0.5 0.3 0.2 0.2 0.2 28.5-29.5 16.8-17.8 Rest

Physical properties

Density g/cm3 8.25
Curie Point 430
Resistivity μ?· m 0.48
Tensile strength Mpa Cold state  
Annealing 520
Yield strength Mpa Cold state  
Annealing 330
Elongation % Cold state  
annealing 30


Type Size/mm Deliver State
Bar 5.0-8.0 Cold Drawn
8.0-30.0 Hot rolling
30.0-180.0 Hot forging
Plate 3.5-30.0 Hot rolling
30.0-40.0 Hot forging
Strip 0.2-3.5 Cold rolling
Flat wire 0.5-5.0 Hot rolling
Round wire 0.1-5.0 Cold Drawn
Capillary OD8.0-1.0,ID0.1-8.0 Cold Drawn
Pipe OD120-8.0, ID8.0-129 Cold drawn