Electrical Conductivity
Also: Conductivity, Specific conductivity, Electrical conductance
Electrical conductivity describes how well a material conducts electric current, and in precious metals it is an important quality characteristic for industrial applications.
Electrical conductivity (symbol: σ, unit: siemens per metre, S/m) indicates how easily electrical charge carriers - in metals these are freely mobile electrons - can flow through a material. The higher the value, the lower the resistance the material offers to the flow of current. For silver and copper this property is of outstanding industrial importance.
Physical background
The reciprocal of conductivity is the specific electrical resistance ρ (unit: ohm-metre, Ω·m). Both quantities are related through:
σ = 1 / ρ
In metals the conduction electrons are scattered by the crystal lattice. Elevated temperature, lattice defects and foreign atoms (alloying components) intensify this scattering and lower the conductivity. Pure, single-crystal metal therefore always has a higher conductivity than an alloy of the same base metal.
Conductivity of the most important precious metals compared
| Metal | σ (x 10⁶ S/m) | Rank | Typical application |
|---|---|---|---|
| Silver (Ag) | 63.0 | 1 (all metals) | Conductor tracks, contacts, solar cells |
| Copper (Cu) | 59.6 | 2 | Cables, circuits, transformers |
| Gold (Au) | 45.2 | 3 | Connectors, bond wires, microprocessors |
| Aluminium (Al) | 37.7 | - | High-voltage lines |
| Palladium (Pd) | 9.5 | - | Connector contacts, catalysts |
| Platinum (Pt) | 9.4 | - | Temperature sensors (PT100/PT1000) |
Silver leads the ranking of all metals - a fact that partly supports the silver price through industrial demand. Copper is, despite slightly lower conductivity, the most widely used conductor material because it is considerably cheaper and more abundantly available. Gold impresses in electronics not through peak conductivity but through its exceptional corrosion resistance - gold-plated contacts do not oxidise and remain permanently reliable.
Influence of temperature and alloying
- Temperature dependence: Metals become poorer conductors as temperature rises (positive temperature coefficient). At 0 °C the conductivity of copper is about 12% higher than at 25 °C.
- Alloying effect: Sterling silver (92.5% Ag, 7.5% Cu) has a conductivity roughly 55% lower than pure silver (approx. 28 instead of 62 MS/m). For high-precision conductor tracks, fine silver (≥ 999/1000) is therefore preferred.
- Cryogenic range: Many metals become superconducting at very low temperatures (σ → ∞); gold and copper, however, do not - they remain ordinary conductors.
Significance for industry and the precious metals market
Around 50% of global silver demand is attributable to industrial applications, including photovoltaic silver paste, solder and electrical contacts. This baseline demand gives the silver price a stable industrial component, independent of investment interest. Gold is used as a thin film (bond wires, connectors) in the semiconductor industry because its oxidation protection works reliably for decades.
You can determine the current melt value of your silver or gold holdings with our melt value calculator.
In brief
Silver is the most electrically conductive of all metals and therefore plays a key role in the electronics and solar industries. Gold impresses in high-reliability applications through its freedom from oxidation, not through peak conductivity. Conductivity falls with rising temperature and with every alloying addition - purity pays off electrically.