Kovar Expansion Precision Alloy Ni29co18 Uns K94610 (4J29)

Product Description

Description:  

4J29(China); 29H, 29H-B, Techallony(Russia); Kovar, Rodar, Glasseal 29-17(United States); Nilo K, Telcaseal(Great Britain); KV-1, KV-2, KV-3(Japan); Dilver P0, Dilver P1(France); Vacon 12, Silvar 48(Germany).

4J29 expansion alloy, also known as Kovar alloy, is a Nickel Iron alloy with 29% Nickel, 17% Cobalt and the remaining balance is Iron. The expansion characteristics of Kovar match both borosilicate (or Pyrex) glasses and alumina ceramics, making it one of the most popular controlled expansion alloys for hermetic sealing applications. Kovar is produced to ensure good properties for machining and deep drawing, and is a porosity free product. You'll find Kovar in applications such as power tubes, microwave tubes, transistors, diodes, hybrid packages, and other kinds of scientific instruments.

Application:
The alloy is widely used as glass sealing for electronic vacuum devices, such as launching tube, oscillating tube, ignitron, magnetron, transistor, sealing plug, relay, leading wire of integrated circuit, chassis, shell, scaffold and so on.

Physical Constants:
Density:8.17g/cm³
Specific gravity (g/cm3): 8.36
Melting point(ºC): 1450
Melting heat(calorie/g): 64
Vapour pressure (μ M): 1× 10-6 (1000ºC)
Specific heat(calorie/g/ºC): 0.105 (0ºC)
0.155 (430ºC)
Heat conductivity(calorie/cm· Sec. · ºC): 0.0395 (30ºC)
0.0485(300ºC)
Curie temperature (ºC): 435
γ α Phase-transition temperature(ºC): Below -80

Electrical performance:
Resistivity (μ Ω -mm): 49 (25ºC)