Glass sealed and controllled expansion alloys
* kovar alloy, ASTM F15, Nilo-K, UNS K94610 (FeNi29Co17), Chinese 4J29
*Specifications:ASTM F15; DIN 17745; S.E.W. 385; Werkstoff Nr. 1.3981; AFNOR NF A54-301
4J29 Kovar alloy is Nickel-Iron-Cobalt, controlled expansion alloy containing 29% Nickel. It’s coefficient of expansion
(which decreases with rising temperature to the inflection point), matches the expansion rate of borosilicate glasses
and aluminia ceramics. Applications include glass to metal seals in applications requiring high reliability or resistance
to thermal shock, ie. high~power transmitting valves, transistor leads and heaters and photography flash bulbs.
Table 2 Coefficient of Linear Expansion
Grade | Heat Treatment of the Samples | Average Coefficient of Linear Expansion | ||
20~300℃ | 20~400℃ | 20~450°C | ||
4J29 Kovar | Heat to temperature of 900±20℃ in the hydrogen, hold for 1h; re-heat to 1100±20℃, hold for 15 min.; cooled to 200℃ at a rate less than 5℃/min |
| 4.6~5.2 | 5.1~5.5 |
Table 3 Typical Coefficient of Linear Expansion
Grade | Average Coefficient of Linear Expansion | |||||||
20~200℃ | 20~300℃ | 20~400℃ | 20~450℃ | 20~500℃ | 20~600℃ | 20~700℃ | 20~800℃ | |
4J29 Kovar | 5.9 | 5.3 | 5.1 | 5.3 | 6.2 | 7.8 | 9.2 | 10.2 |
Table 1 Grade & Chemical Composition
Grade | Chemical Composition (%) | ||||||||||
C | P | S | Mn | Si | Cu | Cr | Mo | Ni | Co | Fe | |
4J29 Kovar | ≤ |
|
|
| |||||||
0.03 | 0.020 | 0.020 | 0.5 | 0.30 | 0.20 | 0.20 | 0.20 | 28.5~29.5 | 16.8~17.8 | Bal. | |
Similar Grades just for customers’ reference
Russia | U.S.A. | U.K. | France | Germany |
29HK | Kovar | Nilo K | Dilver P0 | Vacon 12 |
Kovar Application
Kovar alloy 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 intergrated circuits,
it has been used for the flat pack and the dual-in-line package.
Sheet/Plate, Bar/Rod/Wire/Coil,Capillary/Pipe/Tube
Note: We could do any other products with specified technical standard, say, ASTM,SAE,DIN,S.E.W.,JIS,ISO,
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