Controlled Expansion Alloys

NAS 42

An Fe-42% Ni alloy, NAS 42 has a coefficient of thermal expansion close to that of silicon, ceramic and glass. In addition to integrated circuit lead frames, applications include the manufacture of vibrating plates and metal masks. NAS 42 is also used as a soft magnetic material.

  • Image: Coil
    Coil
  • Image: Sheet
    Sheet

Designation / Standard

Nippon Yakin Grade ASTM B753 EN JIS
NAS 42 UNS K94100 1.3917 ―

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Chemical Composition

NAS 42

  C Si Mn P S Ni Cr Fe
Min ― ― ― ― ― 40.0 ― Balance
Max 0.03 0.30 0.80 0.025 0.025 43.0 0.25

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Physical Properties

Specific heat (J/kg･K) 176.7
Specific resistivity (μΩ･cm) 20℃ 63
Thermal conductivity (W/m･K) 15.5
Coefficient of thermal expansion (10-7/℃) 30–400℃

46
30–450℃

70
Young's modulus (MPa) 147,100
Curie point (℃) 340

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Coefficient of thermal expansion

The coefficient of thermal expansion approximates silicon and ceramic

Coefficient of thermal expansion of NAS 36, NAS 42 (Annealed at 900℃ for 1hr in vacuum)

Image: Coefficient of Thermal Expansion

Mean coefficient of thermal expansion of Fe-Ni alloy

Image: Mean coefficient of thermal expansion of Fe-Ni alloy

Workability

NAS 42 is an excellent choice for use in lead frames when pressing, etching, plating and soldering.

Corrosion resistance

Because NAS 42 does not have the active chromium found in stainless steel, care must be taken to ensure rusting does not occur.

Applications

Integrated circuit lead frames, electron tube sealing, magnetic material

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