Silver Material Science Reference — Alloy Properties × Application
MATERIAL SCIENCE · 5 ALLOYS × 12 PROPERTIES
Silver Material Science Reference
A single-page engineering reference for the five common silver alloys: composition, physical and mechanical properties, electrical and thermal characteristics, oxidation and tarnish behavior, processing, price. Properties grouped for materials-science, metallurgy, and engineering coursework. Standards-linked.
Silver alloy material science reference for engineering, materials science, and metallurgy research. Properties include density, melting point, hardness, tensile strength, elongation, electrical conductivity, thermal conductivity, thermal expansion, oxidation onset, tarnish rate, annealing range, and price. Coverage of fine silver, Britannia, sterling, Argentium, and coin silver alloys per ASTM B413, B742, ISO 9202, ISO 11427. References USGS Mineral Commodity Summaries, NIST WebElements, ASM Handbook. Applications span electrical contacts, brazing, jewelry, antimicrobial coatings, photographic emulsions, mirror coatings, solar photovoltaics, and historical coinage. For materials engineering, industrial applications, standards, scholarship, research, library reference, instruction.
Hover any row to see the property note. Highlighted alloy also dims unrelated applications below.
Properties matrix
| Property | Fine Silver (999) | Britannia (958) | Sterling (925) | Argentium 935 | Coin Silver (900) |
|---|---|---|---|---|---|
| Composition | Ag 99.9% / Other 0.1% | Ag 95.84% / Cu 4.16% | Ag 92.5% / Cu 7.5% | Ag 93.5% / Cu 5.4% / Ge 1.1% | Ag 90% / Cu 10% |
|
Density
Increases with Ag fraction; alloyants Cu (8.96) and Ge (5.32) are less dense.
|
10.49 g/cm³ | 10.4 g/cm³ | 10.36 g/cm³ | 10.4 g/cm³ | 10.31 g/cm³ |
|
Melting Point
Sterling and Coin show eutectic minimum near Ag-Cu eutectic 779 °C; Argentium Ge raises liquidus slightly.
|
961.8 °C | 940 °C | 893 °C | 904 °C | 875 °C |
|
Hardness (annealed)
Vickers hardness; cold-worked values can be 2-4× higher (e.g. sterling cold-worked ≈ 130 HV).
|
25 HV | 50 HV | 60 HV | 70 HV | 65 HV |
|
Tensile Strength (annealed)
Engineering yield is typically 60% of UTS; full cold-work increases ~3×.
|
125 MPa | 280 MPa | 290 MPa | 340 MPa | 305 MPa |
|
Elongation at Break
Workability indicator; pure silver is most ductile but lowest hardness.
|
50 % | 35 % | 30 % | 35 % | 28 % |
|
Electrical Conductivity
Pure silver is reference 105% IACS (highest of any element); Cu reduces conductivity.
|
105 %IACS | 95 %IACS | 87 %IACS | 90 %IACS | 85 %IACS |
|
Thermal Conductivity
Tracks electrical conductivity (Wiedemann-Franz law); used in thermal-management PCB layers.
|
429 W/m·K | 405 W/m·K | 360 W/m·K | 380 W/m·K | 350 W/m·K |
|
Coefficient of Thermal Exp.
Cu addition slightly raises CTE; relevant for joining to ceramic/glass.
|
18.9 10⁻⁶/K | 19.1 10⁻⁶/K | 19.6 10⁻⁶/K | 19.4 10⁻⁶/K | 19.7 10⁻⁶/K |
|
Oxidation Onset (air)
Argentium's Ge forms passivating GeO₂ surface layer, suppressing firescale and tarnish.
|
200 °C | 180 °C | 170 °C | 290 °C | 165 °C |
|
Tarnish Rate (lab Ag₂S)
Cu fraction drives sulfide tarnish (H₂S response); Argentium is ~5× more tarnish-resistant than sterling.
|
1.0 rel. | 1.4 rel. | 2.0 rel. | 0.4 rel. | 2.2 rel. |
|
Annealing Range
Soak temperature for full recrystallization; quench-from-red typical (water for Cu alloys).
|
600 °C | 650 °C | 650 °C | 700 °C | 650 °C |
|
Reference Price
Approximation at LBMA spot ~$0.95/g pure (Q4 2024); alloy price = Ag-fraction × spot + processing margin.
|
0.95 USD/g (raw) | 0.91 USD/g (raw) | 0.88 USD/g (raw) | 0.92 USD/g (raw) | 0.86 USD/g (raw) |
Property values from ASM Handbook Vol 2, NIST WebElements, ASTM B413/B742, ISO 9202, and Argentium International technical data. Annealed-state values; cold-worked properties differ.
Application examples
Where the alloy is the engineering choice, what drives that choice, and the application area where the property matters most.
| Application | Typical alloy | Why |
|---|---|---|
| Electrical contacts (relays, breakers) | Fine Silver (999) | Highest conductivity required; soft pure-silver contacts deform under load → fine-silver-CdO composites used industrially. |
| Solar PV front-side metallization | Fine Silver (999) | Ag pastes screen-printed on c-Si cells; ~10% of annual silver demand. Fineness ~99.99%. |
| Brazing alloys (BAg series) | Sterling (925) | AWS BAg-1 (Ag45-Cu-Zn-Cd) and BAg-7 (Ag56-Cu-Zn-Sn) — sterling-equivalent fine silver alloyed for joining. |
| Jewelry (durability + workability) | Sterling (925) | Sterling balances tarnish resistance, hardness, malleability, and cost; legal definition: ≥ 92.5% Ag. |
| Tarnish-resistant jewelry (firescale-free) | Argentium 935 | Argentium 935 (with germanium) self-passivates; preferred for high-polish settings and white-finish. |
| Hollowware & flatware (historical) | Britannia (958) | Britannia silver — Mandatory in England 1697–1720 to discourage melting of sterling coinage. |
| Coinage (numismatic & investment) | Coin Silver (900) | U.S. Coinage Act of 1837 set 90% Ag/10% Cu as the dime/quarter/half-dollar standard until 1965. |
| Antimicrobial coatings (medical) | Fine Silver (999) | Pure silver thin films (Ag-NPs) for catheters, wound dressings; mechanism: Ag⁺ release. |
| Photographic emulsions (declining) | Fine Silver (999) | Silver halide gelatin; demand fell from ~7,000 t/year (2000) to ~2,000 t/year (2023). |
| Mirror coatings (telescopes, low-emissivity) | Fine Silver (999) | Vacuum-deposited fine silver; protected by SiO₂ overcoat to prevent sulfide attack. |
Standards and primary references
- ASTM B413 — Standard Specification for Refined Silver. Defines fine-silver (≥ 99.90% Ag) commercial purity grades for industrial use.
- ASTM B742 — Standard Specification for Standard Silver-Copper Alloys. Sterling (925), Coin (900) and related Ag-Cu wrought / cast alloys.
- ISO 9202 — Jewellery — Fineness of precious metal alloys. International fineness standard for silver, gold, platinum, palladium jewelry alloys.
- ASTM E1473 — Standard Test Methods for Chemical Analysis of Nickel, Cobalt, and High-Temperature Alloys. Procedural methodology occasionally referenced for trace-element silver analysis.
- ISO 11427 — Determination of silver — Volumetric (potentiometric) method using potassium bromide. Reference method for determining silver content in jewelry alloys.
- USGS Mineral Commodity Summaries — Annual silver production, consumption, reserves. USGS annual report — definitive public source for global silver supply data.
- NIST WebElements — Silver — element properties reference. NIST atomic and isotopic data for elemental silver.
- ASM Handbook Vol 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials. Comprehensive engineering reference for silver alloy properties.
Notes for educators
This reference is suitable for: introductory materials-science laboratories illustrating electrical-conductivity rankings of pure metals; phase-diagram exercises (Ag-Cu eutectic at 779 °C, 28.1 wt% Cu); processing labs comparing annealed vs cold-worked properties; sustainability modules on solar-PV silver demand and recycling.
Calibration caveats
- Property scatter. Mechanical values (hardness, tensile) are highly process-dependent. The values above are typical annealed reference values; fully cold-worked silver alloys can exceed annealed hardness by 2–4×.
- Tarnish "rate". The relative tarnish-rate column is normalized to fine silver = 1.0 in a controlled H₂S environment. Real-world tarnish depends on ambient sulfur, humidity, body chemistry, and surface finish.
- Argentium Ge content. Argentium is a trademarked alloy family; values are for Argentium 935 grade. The germanium percentage may vary 0.8–1.2% by manufacturer batch.
- Reference price. Updated infrequently; for current prices consult the London Bullion Market Association (LBMA) silver fix.
Cross-references in this library
For history, hallmarks, and consumer-facing details on these same alloys, see:
About this library. 25hours is an independent sterling silver jewelry brand.
This page is part of our Silver Reference Library — a contribution to public materials-science
and engineering reference. Compiled from published standards (ASTM, ISO), USGS Mineral Commodity
Summaries, NIST, ASM Handbook, and the Argentium International technical data sheet. We are not
a research institution. Free to cite with attribution. Errors or corrections:
support@25hours.net.