Corson Alloys


High Conductivity Corson Alloy
NKC4419 (UNS Alloy No. C64800)


Recent years have witnessed demand for copper alloy materials with higher electrical conductivity and excellent spring properties. Such materials can control the temperature rise from current flowing in connectors as they become more compact and current values increase. We developed the high conductivity Corson alloy NKC4419 to meet such demand. Along with high conductivity, it has excellent spring properties, bend formability, and thermal resistance. It is ideal for use where connectors for in-vehicle electronics, consumer electronics, or information devices must withstand particularly high current.


  1. 1.High electrical conductivity 65% IACS: higher conductivity than conventional Corson alloys
  2. 2.High Yield strength of 650 MPa
  3. 3.Excellent bend formability (MBR/t = Minimum bend radius/Thickness = H material: 0.7, 1/4H material: 0.0 bad way)
  4. 4.Excellent stress relaxation resistance (stress relaxation rate 23% at 150℃, 1,000 hours)

Table 1. NKC4419 chemical composition (%)

  Cu Co Si
Standard composition Remainder 1.9 0.44
  • Note that all numerical values shown are typical values.

Table 2. Physical properties of NKC4419

Electrical conductivity 65 %IACS (@20℃)
Specific resistance 27 nΩ·m (@20℃)
Thermal conductivity 260 W/mK
Linear expansion coefficient 17.8 ×10-6/K (20 to 300℃)
Modulus of elasticity 127 GPa
Density 8.85 g/cm3
  • Note that all numerical values shown are typical values.

Table 3. Mechanical properties of NKC4419
(upper: typical values, lower: specification range)

Temper Tensile strength
Yield strength
Vickers hardness
1/4H 600
H 670
  • Note that all numerical values shown are typical values.

Table 4. NKC4419 bend formability

Temper MBR/t
Good way Bad way
1/4H 0.3 0.0
H 1.7 0.7
  • MBR/t:Minimum Bend Radius without cracking / thickness
  • Note that all numerical values shown are typical values.
    Please inquire about bend formability of different thicknesses.

Temperature rise during current flow

  • Test piece size (thickness × width × length): 0.15 mm × 1 mm × 30 mm
  • Current:1~5A
  • For reference purpose only. They are observed values, not guaranteed values.
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