4J29 (Kovar) Precision Fe-Ni-Co Glass-to-Metal Sealing Alloy Wire for Hermetic Seals, Electronic Components, Vacuum Devices, Connectors and Aerospace Applications
4J29 Alloy Wire (Kovar Wire) is a precision iron-nickel-cobalt low-expansion sealing alloy designed for glass-to-metal sealing applications. It offers excellent thermal expansion compatibility, good mechanical strength, and reliable hermetic sealing performance. Its coefficient of thermal expansion closely matches that of hard glass and borosilicate glass over a specified temperature range, making it an ideal material for Glass-to-Metal Seals (GTMS).
The alloy wire features excellent cold workability, weldability, dimensional stability, and consistent surface quality. Manufactured under strict chemical composition control and optimized heat treatment processes, 4J29 wire provides stable microstructure, reliable performance, and high production consistency.
4J29 alloy wire is widely used in aerospace, military, electronics packaging, vacuum devices, relays, sensors, RF connectors, integrated circuit packages, power feedthroughs, cable sealing assemblies, and other hermetically sealed electrical and electronic components requiring long-term reliability.
Various wire diameters, coil or straight wire forms are available. Customized dimensions, tolerances, surface finishes, and packaging can also be provided according to specific customer requirements.
1. Chemical Composition:
|
Ni |
28.5-29.5 |
|
C |
≤0.03 |
|
Fe |
Bal |
|
Co |
16.8-17.8 |
2. Technical Specifications:
|
Parameter |
Specification |
|
Max continuous Operating Temperature(℃) |
450℃ |
|
Resisivity(μΩ·m) |
0.49 μΩ·m |
|
Density(g/m³) |
8.17 |
|
Thermal Conductivity (W/m·K, 20°C) |
17.3 |
|
Tensile strength(N/m㎡) |
490-690mpa |
|
Melting point(℃) |
1450℃ |
|
Hardness(Hv) |
140-220Hv |
|
Elongation(%) |
≥20% |
3. Production Attributes
|
Product Form |
4J29 wire |
|
Diameter |
customization |
|
Surface Finish |
Bright, Polished |
|
Packaging Type |
Coil, Bundle, Straight Rods |
|
Certification |
ISO9001, SGS, and so on |
|
Application Environment |
Chemical, Industrial,Home |
4.Applications
- Glass-to-Metal Seals (GTMS)
- Hermetic Connectors
- Electrical Feedthroughs
- Cable Sealing Components
- Hermetic Cable Assemblies
- Electronic Packaging
- Semiconductor Packages
- Integrated Circuit (IC) Packages
- Vacuum Tubes
- Vacuum Electronic Devices
- Relays
- Reed Switches
- Pressure Sensors
- Temperature Sensors
- RF & Microwave Connectors
5.Key features
- Excellent matching thermal expansion (core advantage)
- Stable metallurgical structure
- Standard chemical composition (Fe-Ni-Co controlled expansion alloy
- Good mechanical & processing performance
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