Alloy 42 Supplier
Alloy 42 is an iron-nickel alloy, consisting of 42% nickel. This controlled expansion alloy has low thermal expansion characteristics over a range of temperatures and has been developed over time with ceramics in mind.
Low Thermal Expansion alloys are perfectly suited for use in glass and ceramic seals, providing metallic feed‐throughs from interior to exterior components. At City Special Metals, we ensure that every alloy is manufactured to provide the ideal coefficient. Alloy 42 is available in a range of forms including Round Bar, Sheet, and Coil.
Our alloys are reliable and provide perfect hermetically sealed connections. This particular alloy has few limitations in its use and is ideal for use in annealed plates, sheets and rods.
Do you have applications Alloy 42 would be suited to? Speak to us today and receive expert advice from a leading UK speciality metals stockist.
Alloy 42 Stock
Alloy 42, and similarly Kovar, should always be manufactured according to exact requirements. In ceramics, a low coefficient of thermal expansion (CTE) of must be matched by the feed‐through metal.
| Product Form | Range From | Range To | |
|---|---|---|---|
 | Alloy 42 Round Bar | 4mm | 127mm |
 | Alloy 42 Sheet & Coil | 0.015mm | 3.2mm |
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Alloy 42 Properties
- Shock-resistant
Their coefficient thermal expansion makes the seal resistant to shock and cracking - Ability to withstand extreme temperatures
Low thermal expansion over a range of temperatures - Flexibility
Good workability, weldability and easy-to-machine
Alloy 42 Applications
- Electronic components such as: semiconductor packages, tubes, CRT electron guns, automotive & industrial lamps
- Lead frames
- Thermostat bimetal
Alloy 42 Markets
- Chips & Semiconductors
- Automotive
- Computing
- Lighting
Invar 42
Alloy 42 is also known commercially as Invar 42, NILO 42 and FeNi42, and is identified by the material designation UNS K94100. This iron nickel alloy 42 may be supplied to specifications including ASTM F30, DIN 17745 and MIL-I-23011 Class 5, depending on the required product form, condition and application. Please contact our team to confirm availability and certification against your required specification.
Alloy 42 Composition
| Mechanical Properties | ||
|---|---|---|
| Metallurgical Condition | Annealed, Descaled | |
| Yield Strength | KSI (MPa) | 36 (248) Max |
| Tensile Strength | KSI (MPa) | 71 (490) Max |
| Hardness | HB | |
| Elongation | 50mm | >40 |
| Co Efficient of Thermal Expansion | ||
|---|---|---|
| 30-300°C | 10-6/°C | 4.6 |
| 30-350°C | 10-6/°C | 5.05 |
| 30-400°C | 10-6/°C | 6.12 |
| Density | g/cm³ | 8.15 |
| Curie Temp | °F (°C) | 626 330 |
| Melting Point | °F (°C) | 2597 1425 |
| Modulus of Elasticity at 20°C | MPa | 148 |
| Specific Heat at 20°C | J/g- °C | 0.50 |
| Thermal Conductivity at 20°C | J/cm.s.°C | 12.5 |
| Resistivity at 0°C | Μohm.cm | 63 |
| Poisson’s coefficient | 0.25 |
| Technical Specifications | ||
|---|---|---|
| ASTM | UNS | Werkstoff |
| F1684 | K94100 | 1.3917 |
| Chemistry | ||
|---|---|---|
| Nickel | Ni | 42 |
| Iron | Fe | Balance |
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We can distribute metals across the globe, including locations in Europe, The Middle East, The Far East and the Americas.
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+44 1909 519 189
Speak to the Sales Team
sales@cityspecialmetals.com
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More about Alloy 42
Alloy 42 is widely used for military applications. Its hermeticity and attachability to low‐CTE die to low‐CTE lead frames have been cited as the 2 main advantages of using Alloy 42. However, when placed into plastic components, Alloy 42 has proven to provide disastrous results.
City Special Metals understands that mismatching can take place with Alloy 42, whether that be a result of surface mount (SM) solder joints connecting materials with different CTEs, or when solder bonds have CTEs that differ from the CTE of solder. We’ll work alongside you to ensure that the desired result is found, with little-to-no SM solder joint failures.
Alloy 42 and Kovar not only cause significant global and local thermal expansion mismatches, but are inherently more difficult to solder because of the low solubility of nickel and iron, the main constituents of these alloys. Pull tests of solder joints show that, under the best of circumstances, a solder joint that includes an Alloy 42 or Kovar surface is only half as strong as one made to copper surfaces.
Alloy 42 is also known by the following trade names;
- N42®
- Nilo 42®
- Dilaton 41®
- Pernifer 42®
- Glass Seal 42®
Have any other alloy requirements? See a list of our specialist alloys here. If you can’t find what you’re looking for there, click the following link for other speciality alloys we stock.
Alloy 42 FAQs
What is Alloy 42, and what are its key properties?
Alloy 42, also known as FeNi 42, is a nickel–iron alloy containing about 42% nickel. It has a low and stable coefficient of thermal expansion, making it ideal for use with glass, ceramics, and silicon. The alloy offers good mechanical strength, workability, and weldability, making it suitable for precise electronic and sealing applications.
What are the typical applications of Alloy 42?
Alloy 42 is used in the electronics and semiconductor industries where expansion matching is critical. It is common in glass-to-metal seals, lead frames for integrated circuits, lighting components, and transformer bushings. It ensures stability and durability in devices exposed to temperature variations.
What are the uses of Alloy 42 Round Bar?
Alloy 42 round bar is used for pins, leads, and rods in electronic and hermetic assemblies where thermal expansion must be controlled.
What are the uses of Alloy 42 Sheet?
Alloy 42 sheet is used for covers, lids, and base plates in hermetic packaging and electronic housings that require high dimensional accuracy.
What are the uses of Alloy 42 Coil?
Alloy 42 coils and strips are used for high-volume manufacturing of electronic lead frames, connectors, and sealing rings where consistent expansion and precise stamping are needed.
