-
Alfred***We received the goods, everything went fine. Perfect packaging, good product quality, good price - we are satisfied.
-
May***The product quality is very good, beyond my expectations, the actual use of fully meet my needs, we will buy again.
-
Matthew***I bought low expansion alloy from Joy, She is a very responsible lady, Tankii's products quality is pretty good.
4J42 Low Expansion Alloy Wire for Vacuum Devices and Semiconductor Seals

Contact me for free samples and coupons.
WhatsAPP:0086 18588475571
Wechat: 0086 18588475571
Skype: sales10@aixton.com
If you have any concern, we provide 24-hour online help.
xCTE (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 | Diameter | 0.02 Mm – 3.0 Mm |
Condition | Annealed Or Cold Drawn | Customization | Available On Request |
Highlight | 4j42 low expansion alloy,4j42 cobalt chromium alloy |
Attribute | Value |
---|---|
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 |
Diameter | 0.02 mm – 3.0 mm |
Condition | Annealed or cold drawn |
Customization | Available on request |
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.
- Nickel (Ni): ~42%
- Iron (Fe): Balance
- Minor elements: Mn, Si, C (trace amounts)
- 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
- 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
- Glass-to-metal hermetic seals
- Semiconductor lead frames
- Electronic relay headers
- Infrared and vacuum sensors
- Communication devices and packaging
- Aerospace connectors and enclosures
- Vacuum packaging or plastic spools
- Anti-corrosion treatment
- Air/sea/express delivery available
- Delivery time: 7-15 business days



