High Precision 4J33 Sealing Wire Controlled Expansion Alloy For Hermetic Packaging

High Precision 4J33 Sealing Wire Controlled Expansion Alloy For Hermetic Packaging

Product Overview

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.

Material Composition

• 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

Available Specifications

• 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

Key Features

• 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

Typical Applications

• Glass-to-metal hermetic seals

• Vacuum tubes and infrared sensors

• Relay housings and electronic packaging

• Optical device enclosures

• Aerospace-grade connectors and leads

Packaging & Shipping

• Standard plastic spool, vacuum-sealed or custom packaging

• Delivery via air, sea, or express

• Lead time: 7–15 working days depending on order size

High Precision nickel alloy wire

High Precision glass sealing alloy

high Strength glass sealing alloy

High Precision 4J33 Sealing Wire Controlled Expansion Alloy For Hermetic Packaging Images