4J42 Low Expansion Alloy Wire for Vacuum Devices and Semiconductor Seals

Product Overview

4J42 wire is a precision-controlled expansion alloy composed of iron and approximately 42% nickel. It is engineered to closely match the thermal expansion of borosilicate glass and other packaging materials, making it an ideal choice for hermetic sealing, electronic packaging, and aerospace applications.

Chemical Composition

• Nickel (Ni): ~42%

• Iron (Fe): Balance

• Minor elements: Mn, Si, C (trace amounts)

CTE (Coefficient of Thermal Expansion, 20–300°C): ~5.5–6.0 × 10⁻⁶ /°C
Density: ~8.1 g/cm³
Electrical Resistivity: ~0.75 μΩ·m
Tensile Strength: ≥ 430 MPa
Magnetic Properties: Soft magnetic, low coercivity

Specifications

• Diameter: 0.02 mm – 3.0 mm

• Surface: Bright, oxide-free

• Form: Spool, coil, cut-to-length

• Condition: Annealed or cold drawn

• Customization: Available on request

Key Features

• Matched thermal expansion for glass and ceramics

• Stable mechanical and magnetic properties

• Excellent vacuum compatibility

• Ideal for electronic sealing, relays, and sensor leads

• Low expansion with good ductility and weldability

Applications

• Glass-to-metal hermetic seals

• Semiconductor lead frames

• Electronic relay headers

• Infrared and vacuum sensors

• Communication devices and packaging

• Aerospace connectors and enclosures

Packaging & Shipping

• Vacuum packaging or plastic spools

• Anti-corrosion treatment

• Air/sea/express delivery available

• Delivery time: 7–15 business days

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Huona (Shanghai) New Material Co., Ltd. Was established in 2008, currently have three divisions: Magnesium Division, Thermal Spray Division and Functional Material Division.

Magnesium Division produces magnesium metal products. Various models of high-quality magnesium alloy plate, magnesium rods, high-purity magnesium, magnesium plate, magnesium die casting, magnesium extrusion profiles and other metal magnesium and deep processing products.

Thermal spray wire Division offers a wide variety of pure metal and metal alloy wires, including nickel-, iron-, aluminum-, and zinc-based wires for thermal spray projects.

Fuctional Material Division supply electronic packaging COMPONENTS(GTMS, CTMS), soft magnetic alloys and bimetal strip.

Our company is certified by ISO9001 quality system and ISO14001 environmental protection system.

Mission Statement

We try our best to understand and utilize information within the environment. With this competency, we assist customers to create added value and contribute to the development of industry and healthy living.

We strive for "Best, " welcome challenges, and are relentless till we deliver products and solutions.