Base elements → Materials → Metallic materials

COPPER

Table of main properties of copper

 

Property Typical Value Remarks
Density ~8.9 g/cm³ High
Young’s modulus (E) ~110–130 GPa Moderate
Tensile strength ~200–400 MPa Depends on state
Hardness (HV) ~50–120 HV Low to moderate
Thermal conductivity ~380–400 W/m·K Very high
Electrical conductivity ~58–60 MS/m Very high
Thermal expansion ~16–17 ×10⁻⁶ /K Moderate
Melting point ~1085 °C Pure copper
Magnetism No Non-magnetic
Corrosion resistance Good Forms patina
Machinability Good

Copper is a non-ferrous metal widely used in watchmaking, primarily as a base element in alloys (brass, bronze, nickel silver), and more rarely in near-pure form for specific applications. With its excellent thermal and electrical conductivity, high ductility, and good formability, it has historically played a fundamental role in the development of watchmaking materials.

Today, its direct use is almost exclusively limited to dials, due to its low mechanical strength and sensitivity to oxidation. It nevertheless remains omnipresent through the alloys used in movement manufacturing.

Main Properties

Copper exhibits several important characteristics:

  • Very high thermal and electrical conductivity
  • Excellent ductility and malleability
  • Low mechanical strength
  • Good corrosion resistance, but visible oxidation (patina)
  • Moderate Young’s modulus (~110–130 GPa)
  • Non-magnetic material

These properties make copper particularly suitable for use in technical alloys.

1. Pure Copper

Used in a limited manner in modern watchmaking.

Applications:

  • Dials (often as a base material)

Characteristics:

  • Easy to work
  • Warm appearance (reddish-orange color)
  • Sensitive to oxidation (patina formation)

2. Copper in Alloys

Copper is the primary element in many watchmaking materials:

It contributes:

  • Ductility
  • Machinability
  • Stability

Due to its sensitivity to oxidation, copper is generally treated:

These treatments help stabilize the appearance and improve durability.

Today, copper is mainly used for:

  • Dials (as a base material before finishing)
  • Certain decorative components (primarily in clockmaking)
  • Technical movement alloys

Its direct structural use is very limited.

Advantages

  • Excellent conductivity
  • Very high formability
  • Warm aesthetic appearance
  • Non-magnetic
  • Essential base material for watchmaking alloys

Limitations

  • Low mechanical strength
  • Sensitivity to oxidation (tarnishing, patina)
  • Poor wear resistance
  • Limited suitability for functional components
  • Limited direct use in modern watchmaking