Fe-Ni-Co Kovar Alloy 4J29 Bar - ASTM F15 Sealing Material with 29% Nickel Content for Glass-to-Metal Applications
Premium ASTM F15 precision alloy with controlled thermal expansion properties for glass-to-metal sealing applications.
Kovar Alloy 4J29, also known as ASTM F15, Nilo-K, UNS K94610 (FeNi29Co17), is a nickel-iron-cobalt controlled expansion alloy containing 29% nickel. Its coefficient of expansion decreases with rising temperature to match borosilicate glasses and alumina ceramics, making it ideal for reliable glass-to-metal seals.
- Material: Kovar Alloy 4J29 (FeNi29Co17)
- Standards: ASTM F15; DIN 17745; S.E.W. 385; Werkstoff Nr. 1.3981; AFNOR NF A54-301
- Available Forms: Rod, Strip, Wire, Sheet
- UNS Number: K94610
- Glass-to-metal seals requiring high reliability
- Thermal shock resistant applications
- High-power transmitting valves and transistor leads
- Photography flash bulbs and heaters
- Semiconductor device packaging
- Laser and photodetector components
- Aerospace guidance and navigation systems
| Alloy Type | Trade Name | UNS No. | Specifications | Rod | Strip | Wire | Sheet |
|---|---|---|---|---|---|---|---|
| Ni29Co17 | Kovar | K94610 | ASTM F15 | √ | √ | √ | √ |
| FeNi36 | Invar 36 | K93603 | ASTM 1684 | √ | √ | √ | |
| FeNi32Co5 | Super Invar 32-5 | KI93500 | ASTM F1684 | √ | √ | √ | |
| FeNi27Co25 | Ceramvar | F1466 | ASTM F1466 | √ | √ | √ | √ |
| Item | 1J33 | 3J01 | 3J9 | 4J29 | 4J32 | 4J33 | 4J45 | FeNi50 | Invar36 |
|---|---|---|---|---|---|---|---|---|---|
| C | ≤0.05 | ≤0.05 | 0.22-0.26 | ≤0.03 | ≤0.05 | ≤0.03 | ≤0.05 | ≤0.05 | ≤0.1 |
| Mn | ≤0.05 | ≤1.00 | 1.80-2.20 | ≤0.5 | 0.2-0.6 | ≤0.5 | ≤0.8 | ≤0.8 | ≤0.5 |
| Fe | Rest | ||||||||
Kovar's thermal expansion coefficient precisely matches borosilicate glass, providing exceptional stability and reliability in electronic packaging and optoelectronic applications. The alloy offers excellent corrosion resistance, high-temperature performance, and mechanical strength suitable for demanding aerospace and industrial environments.
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