Product Overview

4J45 alloy wire is a controlled thermal expansion Fe-Ni alloy consisting of approximately 45% nickel. It is engineered for applications requiring dimensional stability and hermetic sealing, particularly where thermal compatibility with glass or ceramic is crucial. This material is ideal for use in semiconductor lead frames, sensor housings, and high-reliability electronic packaging.

Material Composition

• Nickel (Ni): ~45%

• Iron (Fe): Balance

• Trace elements: Mn, Si, C

CTE (Coefficient of Thermal Expansion, 20–300°C): ~7.5 × 10⁻⁶ /°C
Density: ~8.2 g/cm³
Electrical Resistivity: ~0.55 μΩ·m
Tensile Strength: ≥ 450 MPa
Magnetic Properties: Weakly magnetic

Specifications

• Diameter range: 0.02 mm – 3.0 mm

• Surface finish: Bright / oxide-free

• Supply form: Spools, coils, cut lengths

• Delivery condition: Annealed or cold-drawn

• Custom dimensions available

Key Features

• Moderate thermal expansion matching glass/ceramic

• Excellent sealing and bonding characteristics

• Good weldability and corrosion resistance

• Dimensional stability under thermal cycling

• Suitable for microelectronics and optical devices

Applications

• Hermetic seals for semiconductors

• Infrared sensor housings

• Relay casings and electronic modules

• Glass-to-metal seals in communication components

• Aerospace-grade packages and connectors

Packaging & Shipping

• Vacuum-sealed or plastic spool packaging

• Custom labeling and bulk options available

• Delivery: 7–15 working days

• Shipping methods: Air freight, sea freight, courier