Silver (Ag)
Silver has the highest electrical and thermal conductivity of any element, making it essential for electronics, solar energy, and brazing. Beyond its industrial roles, silver's antimicrobial properties drive growing applications in medical devices and water purification, while its reflectivity makes it indispensable in mirrors and coatings.
Properties
- Density
- 10,490 kg/m³
- Melting Point
- 962 °C
- Boiling Point
- 2,162 °C
- Thermal Conductivity
- 429 W/(m·K)
- Electrical Resistivity
- 1.59 × 10⁻⁸ Ω·m
- Tensile Strength
- 140–330 MPa
- Yield Strength
- 55–275 MPa
- Hardness
- 25–75 HV
- Elongation
- 25–50%
- Crystal Structure
- FCC
Common Grades
- Ag 999 (Fine Silver): 99.9% pure silver. Electronics, solar cells, investment, laboratory standards.
- Sterling Silver (925): 92.5% silver + 7.5% copper. Jewelry, tableware, decorative items.
- Ag 99.99% (4N): Ultra-high purity for semiconductor and electronics applications.
- Silver-copper brazing alloys: BAg series alloys (Ag content 25–72%). Industrial brazing of steel, copper, and alloys.
Applications
- Electronics: Contact points, switches, conductive pastes, RFID antennas, membrane switches
- Solar Energy: Photovoltaic cell contacts (silver paste), mirrors for concentrated solar power
- Brazing: Silver brazing alloys for joining steel, stainless steel, copper in HVAC, plumbing, tooling
- Medical: Antimicrobial wound dressings, catheter coatings, water purification systems
- Photography & Mirrors: Silver halide film, telescope mirrors, architectural mirror coatings
FAQ
Why is silver essential for solar panels?
Each photovoltaic cell uses silver paste to form the conductive grid that collects generated electricity. Silver's unmatched conductivity maximizes cell efficiency. The solar industry now consumes ~15% of annual silver production (~5,000 tonnes/year), and this is growing rapidly with global solar expansion.
How do silver's antimicrobial properties work?
Silver ions (Ag⁺) disrupt bacterial cell membranes and interfere with DNA replication and respiratory enzymes. This broad-spectrum antimicrobial action is effective against over 650 pathogens including MRSA. Silver nanoparticles are used in wound dressings, medical coatings, and water treatment systems.
What is the difference between silver brazing and soldering?
Silver brazing uses alloys with 25–72% silver content at 620–850°C, producing joints stronger than the base metals (tensile >400 MPa). Soft soldering uses tin-based alloys at 180–320°C with much lower joint strength (~40 MPa). Silver brazing is specified for pressure systems (EN 13134), while soldering suits electronics and low-stress plumbing.