Electrical Conductivity
Also: Conductivity, Specific Conductivity, Electrical Conductance
Electrical conductivity describes how well a material conducts electric current and is an important quality characteristic of precious metals for industrial applications.
Electrical conductivity (symbol: σ, unit: Siemens per metre, S/m) indicates how easily electric charge carriers – in metals these are freely moving electrons – can flow through a material. The higher the value, the lower the resistance the material offers to the current flow. For silver and copper this property is of outstanding industrial importance.
Physical background
The reciprocal of conductivity is the specific electrical resistivity ρ (unit: Ohm·metre, Ω·m). The two quantities are linked by the following relationship:
σ = 1 / ρ
In metals the conduction electrons are scattered by the crystal lattice. Increased temperature, lattice defects and foreign atoms (alloy constituents) intensify this scattering and lower 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 (× 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 power 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 supports the silver price in part through industrial demand. Copper, despite slightly lower conductivity, is the most widely used conductor material because it is significantly cheaper and more abundant. Gold impresses in electronics not through peak conductivity but through its extraordinary corrosion resistance – gold-plated contacts do not oxidise and remain permanently reliable.
Effect 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 reduced by around 55% compared with pure silver (approx. 28 instead of 62 MS/m). Fine silver (≥ 999/1000) is therefore preferred for high-precision conductor tracks.
- Cryogenic range: Many metals become superconducting at very low temperatures (σ → ∞); gold and copper, however, do not – they remain normal conductors.
Significance for industry and the precious metals market
Around 50% of global silver demand is accounted for by industrial applications, including photovoltaic silver paste, solder and electrical contacts. This baseline demand gives the silver price a stable industrial demand 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 over 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 freedom from oxidation, not through peak conductivity. Conductivity falls with rising temperature and with every alloying addition – purity pays off electrically.