Intent: Comparative engineering analysis of electrical conductivity (106% vs 101% IACS), thermal conductivity (429 vs 390 W/(m·K)), noble atmospheric corrosion and sulfidation, contact resistance, and volumetric cost trade-offs in high-performance electrical conductors and switchgear contacts.
Engineering Verdict & When to Choose Each
Silver or copper: compare the complete conductor and contact
By Mat Grades Editorial Desk · Updated 2026-11-14
A bulk conductor and an electrical contact are different selection problems. Compare silver and copper using conductivity values at compatible temperatures and in identified conditions, then assess the complete assembly. A small difference in bulk conductivity does not by itself establish a useful reduction in contact resistance, temperature rise or lifecycle cost.
For a conductor bar, include section, cooling, mechanical support and the allowable operating temperature in the design. For a contact surface, include contact force, movement, contamination and the actual atmosphere. A plated surface on a different substrate is a separate product and process; it should not be treated as equivalent to a solid-metal specimen without suitable evidence.
Quote the same finished requirement when comparing material cost. Include fabrication, any surface treatment, inspection and maintenance rather than using commodity price alone. Test the representative assembly under its real electrical and thermal cycle where the consequence of failure warrants it. Retain the material identity and interface specification with the approval so that a change of coating, supplier or joint detail does not silently invalidate the original selection.
Fine Silver 999: evidence to check
Fine Silver 999 has 16 cataloged property rows. Electrical Conductivity is reported as 106 % IACS (typical; tested at 20 °C). Modulus of Elasticity is reported as 76 GPa (typical; further condition not stated). The record identifies ASTM B742 / B742M; check its scope and ordered edition. These are source-scoped examples rather than unrestricted design allowables. Read the full row context and certificate before using a value for acceptance; an absent value is not zero or a performance failure.
C11000 ETP Copper: evidence to check
C11000 ETP Copper has 199 cataloged property rows. Electrical Conductivity is reported as 101 % IACS (typical; tested at 20 °C). Modulus of Elasticity in Tension is reported as 117210.9 MPa (typical; further condition not stated). The record identifies ASTM B187/B187M; check its scope and ordered edition. These are source-scoped examples rather than unrestricted design allowables. Read the full row context and certificate before using a value for acceptance; an absent value is not zero or a performance failure.
Four questions before approval
- Are compared conductivity values at compatible temperatures?
- Is the design limited by bulk loss or contact behavior?
- Does any proposed plating system have its own qualification?
- Is cost compared through fabrication, inspection and service?
Check the linked material records for the complete source trail. Read the methodology before comparing minimum requirements with typical measurements. No direct substitution or qualified fabrication procedure is implied.
Material Comparison
Compare verified engineering materials side by side with condition-specific mechanical properties.
| Parameter | Fine Silver 999 | C11000 ETP Copper |
|---|---|---|
| Material Family | Silver & Silver Alloys | Copper Alloys |
| Subfamily | Fine Silver | Pure Copper |
| UNS Designation | P07010 | C11000 |
| ISO Designation | Ag99.9 | — |
| ASTM Designation | Grade 99.90 | — |
| DIN Designation | Ag99.9 | — |
| W-Nr Designation | 2.1211 | — |
| UK-HALLMARK Designation | 999 | — |
| SPECIFICATION Designation | ASTM B742 Standard Specification for Fine Silver Contact Material | ASTM B187/B187M |
| COMMERCIAL Designation | — | Electrolytic Tough Pitch |
| Element | Fine Silver 999 | C11000 ETP Copper |
|---|---|---|
| Ag (Silver) | ≥ 99.9% | — |
| Cu (Copper) | ≤ 0.08% | ≥ 99.9% |
| Fe (Iron) | ≤ 0.01% | — |
| Pb (Lead) | ≤ 0.015% | — |
| Bi (Bismuth) | ≤ 0.005% | — |
| Property | Fine Silver 999 | C11000 ETP Copper |
|---|---|---|
| Density · TYPICAL · 20 °CUnit: g/cm³ | 10.49 g/cm³ | 8.885–8.941 g/cm³ |
| Specific Gravity · TYPICALUnit: — | — — | 8.91 — |
| Mechanical Parameter | Fine Silver 999Annealed (Soft) | C11000 ETP Copper1/2 Hard (H02) |
|---|---|---|
| Modulus of Elasticity · TYPICALUnit: | 76 GPa | 117210.9 MPa |
| Poisson's Ratio · TYPICALUnit: dimensionless | 0.37 dimensionless | — dimensionless |
| Yield Strength (0.2% Offset) · Strip, Sheet, Wire, Bar · Annealed (Soft) · TYPICALUnit: MPa | ≥ 40 MPa | — MPa |
| Ultimate Tensile Strength · Strip, Sheet, Wire, Bar · Annealed (Soft) · TYPICALUnit: MPa | ≥ 125 MPa | — MPa |
| Tensile Strength · Flat Products · 0.04 in · 1/2 Hard (H02) · TYPICAL · 20 °CUnit: MPa | — MPa | 289.6 MPa |
| Elongation at Break · Strip, Sheet, Wire, Bar · in 50 mm (2 in) · Annealed (Soft) · TYPICALUnit: % | ≥ 40 % | — % |
| Elongation · Flat Products · 0.04 in · 1/2 Hard (H02) · TYPICAL · 20 °CUnit: % | — % | 14 % |
| Modulus of Rigidity · TYPICALUnit: MPa | — MPa | 44126.4 MPa |
| Machinability Rating · TYPICALUnit: % | — % | 20 % |
| Forgeability Rating · TYPICALUnit: — | — — | 65 — |
| Shear Strength · Flat Products · 0.04 in · 1/2 Hard (H02) · TYPICAL · 20 °CUnit: MPa | — MPa | 179.3 MPa |
| Fatigue Strength · Flat Products · 0.04 in · 1/2 Hard (H02) · TYPICAL · 20 °CUnit: MPa | — MPa | 89.6 MPa |
| Property | Fine Silver 999 | C11000 ETP Copper |
|---|---|---|
| Electrical Conductivity · TYPICAL · 20 °CCategory: ELECTRICAL • Unit: % IACS | 106 % IACS | 101 % IACS |
| Electrical Resistivity · TYPICAL · 20 °CCategory: ELECTRICAL • Unit: nΩ·m | 15.9 nΩ·m | — nΩ·m |
| Thermal Conductivity · TYPICAL · 20 °CCategory: THERMAL • Unit: W/(m·K) | 429 W/(m·K) | 391.15 W/(m·K) |
| Melting Point · TYPICALCategory: THERMAL • Unit: °C | 962 °C | — °C |
| Specific Heat Capacity · TYPICAL · 20 °CCategory: THERMAL • Unit: J/(kg·K) | 235 J/(kg·K) | 385.2 J/(kg·K) |
| Liquidus Temperature · TYPICALCategory: THERMAL • Unit: °C | — °C | 1082.8 °C |
| Solidus Temperature · TYPICALCategory: THERMAL • Unit: °C | — °C | 1065 °C |
| Coefficient of Thermal Expansion (68-212°F) · TYPICALCategory: THERMAL • Unit: µm/(m·K) | — µm/(m·K) | 16.92 µm/(m·K) |
| Coefficient of Thermal Expansion (68-392°F) · TYPICALCategory: THERMAL • Unit: µm/(m·K) | — µm/(m·K) | 17.28 µm/(m·K) |
| Coefficient of Thermal Expansion (68-572°F) · TYPICALCategory: THERMAL • Unit: µm/(m·K) | — µm/(m·K) | 17.64 µm/(m·K) |
| Annealing Temperature Range · RANGECategory: THERMAL • Unit: °C | — °C | 371.1–648.9 °C |
| Hot Working Temperature Range · RANGECategory: THERMAL • Unit: °C | — °C | 760–871.1 °C |
| Hardness Scale | Fine Silver 999 | C11000 ETP Copper |
|---|---|---|
| HV Hardness · Annealed (Soft) · TYPICAL | 25–35 HV | — |
| Rockwell B Hardness · Flat Products · 0.04 in · 1/2 Hard (H02) · TYPICAL · 20 °C | — | 40 HRB |
| Rockwell F Hardness · Flat Products · 0.04 in · 1/2 Hard (H02) · TYPICAL · 20 °C | — | 84 HRF |
| Rockwell 30T Hardness · Flat Products · 0.04 in · 1/2 Hard (H02) · TYPICAL · 20 °C | — | 50 HR30T |
Machinability: Rated at approximately 30% relative to free-cutting brass (C36000). Highly ductile and gummy; produces long continuous chips. Requires sharp high-rake carbide or diamond tooling, light feed rates, and continuous flood coolant to prevent tearing and galling.
Weldability: Weldable with gas tungsten arc (GTAW/TIG) and resistance welding; requires significant preheat and higher heat input due to extremely high thermal diffusivity (1.74 cm²/s). Readily brazed with silver-bearing fluxed fillers.
Formability / Cold Working: Exceptional cold workability. Capable of severe deep drawing, spinning, wire drawing down to micro-diameters, and cold swaging without intermediate annealing.
Heat Treatment & Annealing: Full recrystallization annealing occurs between 200°C and 300°C (392°F to 572°F) for 30 minutes, followed by rapid water quench or air cooling to preserve soft annealed ductility.
Machinability: Machinability rating: 20% relative to free-cutting brass (C36000 = 100%). Forgeability rating: 65.
Weldability: Soldering: Excellent; Brazing: Good; Butt Welding: Good; Gas Shielded Arc Welding: Fair; Oxyacetylene Welding, Coated Metal Arc Welding, Spot Welding, and Seam Welding: Not Recommended.
Formability / Cold Working: Capacity for being cold worked: Excellent; Capacity for being hot formed: Excellent.
Heat Treatment & Annealing: Annealing temperature range: 371.1°C to 648.9°C (700°F - 1200°F). Hot working temperature range: 760.0°C to 871.1°C (1400°F - 1600°F).