Huona (Shanghai) New Material Co., Ltd.
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4J33 alloy wire is a precision low-expansion Fe-Ni-Co alloy material specifically designed for hermetic glass-to-metal sealing applications. With approximately 33% nickel and a small amount of cobalt, this alloy offers a thermal expansion coefficient closely matched to hard glass and ceramics. It is widely used in the manufacture of vacuum tubes, infrared sensors, electronic relays, and other high-reliability devices.
Nickel (Ni): ~33%
Cobalt (Co): ~3–5%
Iron (Fe): Balance
Others: Mn, Si, C (trace amounts)
Thermal Expansion (30–300°C): ~5.3 × 10⁻⁶ /°C
Density: ~8.2 g/cm³
Electrical Resistivity: ~0.48 μΩ·m
Tensile Strength: ≥ 450 MPa
Magnetic Properties: Soft magnetic, good permeability and stability
Diameter: 0.02 mm to 3.0 mm
Surface: Bright, oxide-free
Delivery form: Coils, spools, or cut length
Condition: Annealed or cold-drawn
Custom sizes and packaging available
Excellent match with hard glass for vacuum-tight sealing
Stable thermal expansion for precision components
Good corrosion resistance and weldability
Clean surface finish, vacuum-compatible
Reliable performance in aerospace and electronic applications
Glass-to-metal hermetic seals
Vacuum tubes and infrared sensors
Relay housings and electronic packaging
Optical device enclosures
Aerospace-grade connectors and leads
Standard plastic spool, vacuum-sealed or custom packaging
Delivery via air, sea, or express
Lead time: 7–15 working days depending on order size
