- Precision Iron Nickel Alloy Kovar 4J29 strip / coil / foil
Precision Alloy Kovar alloy is a vacuum melted, iron-nickel-cobalt alloy that is widely used in the electronics industry. Precision Alloy Kovar is a nickel-iron-cobalt, controlled-expansion alloy which contains 29% nickel. Precision Alloy its coefficient of expansion, which decreases with rising temperature to the inflection point, matches the expansion rate of borosilicate glasses and alumina ceramics.
Precision Alloy Kovar alloy has been used for making hermetic seals with the harder Pyrex glasses and ceramic materials. This Precision alloy has found wide application in power tubes, microwave tubes, transistors, and diodes. In integrated circuits, Precision Alloy has been used for the flat pack and the dual-in-line package.
Basic performance: Precision Alloy is divided into low-expansion alloy and fixed-expansion alloy, the latter is also known as sealing alloy. Precision Alloy Expansion alloy besides has the specific thermal expansion coefficient, according to the different USES also requires a good sealing property, weldability and corrosion resistance, machinability and cutting, and in the use of expansion characteristics caused by the temperature range there is no obvious change of phase transformation, Precision Alloy product is commonly bar, sheet, strip, wire and tube and so on.
Precision Alloy Expansion alloy applications: Precision Alloy is widely used in glass, metal and ceramic sealing in avionics and instruments, electric vacuum industry and other electronic devices, electric light source and other fields.
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. |
| Kovar | K94610 | 1.3981 |
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 a,10-6/°C |
| 20-200°C | 20-300°C | 20-400°C | 20-450°C | 20-500°C | 20-600°C | 20-700°C | 20-800°C |
| Kovar | 5.9 | 5.3 | 5.1 | 5.3 | 6.2 | 7.8 | 9.2 | 10.2 |
