Electrical Conductivity
Also: Conductivity, Specific conductivity, Electric 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 charge carriers — in metals these are freely moving electrons — can flow through a material. The higher the value, the lower the resistance the material presents 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 linked by the following relationship:
σ = 1 / ρ
In metals, conduction electrons are scattered by the crystal lattice. Elevated temperature, lattice defects and foreign atoms (alloying constituents) intensify this scattering and reduce conductivity. Pure, single-crystal metal therefore always has 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) | Circuit traces, 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 tops the rankings among all metals — a fact that partly underpins the silver price through industrial demand. Copper is the most widely used conductor material despite its slightly lower conductivity, because it is far cheaper and more abundantly available. Gold wins in electronics not through top 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 roughly 55 % lower conductivity than pure silver (approx. 28 vs. 62 MS/m). Fine silver (≥ 999/1000) is therefore preferred for high-precision circuit traces.
- 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 comes from industrial applications, including photovoltaic silver paste, soldering materials and electrical contacts. This base 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 remains reliable for decades.
The current melt value of your silver or gold holdings can be determined with our Melt Value Calculator.
Key takeaway
Silver is the most electrically conductive of all metals and therefore plays a key role in the electronics and solar industry. Gold excels in high-reliability applications through its freedom from oxidation, not through peak conductivity. Conductivity decreases with rising temperature and with every alloying addition — purity pays off electrically.