1. Chemical Composition
C11000 (Oxygen-Free Copper, OFHC): 99.99% Cu, low oxygen content for high conductivity.
C12200 (Phosphorus-Deoxidized Copper): 99.90% Cu + ~0.02–0.05% phosphorus (to remove oxygen, preventing "hydrogen embrittlement" in high-temperature environments).
Brass: Copper + Zinc (e.g., C26000 "Cartridge Brass": 70% Cu + 30% Zn).
Bronze: Copper + Tin (e.g., C90700 "Naval Bronze": 88% Cu + 10% Sn + 2% Zn) or copper + non-tin elements (e.g., aluminum bronze, silicon bronze).
Copper-Nickel (Cupronickel): Copper + Nickel (e.g., C71500 "70/30 Cupronickel": 70% Cu + 30% Ni).
2. Mechanical Properties
3. Corrosion Resistance
Vulnerable to "dezincification" in chloride-rich environments (e.g., seawater) if impurities are present.
Susceptible to corrosion in ammonia-containing environments (e.g., industrial emissions) or sulfuric acid at high concentrations.
Brass: Good resistance to air and fresh water but poor in seawater (prone to dezincification unless stabilized with arsenic, e.g., C26800 "Arsenical Brass").
Naval Bronze: Excellent resistance to seawater, biofouling (e.g., barnacles), and salt spray-ideal for marine applications.
Copper-Nickel (C71500): Exceptional resistance to seawater corrosion, erosion, and cavitation-used in ship hulls, heat exchangers, and offshore platforms.
Aluminum Bronze: Resists corrosion in harsh environments (e.g., industrial chemicals, saltwater) and has anti-wear properties.
4. Thermal & Electrical Conductivity
Electrical conductivity: ~98–100% IACS (International Annealed Copper Standard)-the benchmark for electrical conductors.
Thermal conductivity: ~390 W/(m·K)-superior for heat transfer applications.
Brass (C26000): Electrical conductivity ~28% IACS; thermal conductivity ~110 W/(m·K).
Copper-Nickel (C71500): Electrical conductivity ~2% IACS; thermal conductivity ~29 W/(m·K).
Bronze: Conductivity varies (e.g., naval bronze: ~15% IACS; silicon bronze: ~30% IACS).
5. Processing & Fabrication
Cold working (drawing, rolling, extrusion) due to high ductility.
Hot working (forging, casting) at moderate temperatures (700–900°C).
Welding (brazing, soldering, TIG/MIG welding) with minimal cracking risk.
Machining: Requires lubrication to prevent sticking (pure copper is "gummy" and can clog cutting tools).
Brass (C26000): Excellent machinability ("free-cutting" with added lead, e.g., C36000 "Free-Cutting Brass") and formability-used for screws, valves, and decorative parts.
Bronze: Harder to machine than brass but can be forged or cast into complex shapes (e.g., bearings, gears).
Copper-Nickel: Difficult to machine due to high toughness-requires sharp tools and slow speeds; welding is feasible with proper technique.
6. Cost
Brass: Lower cost than pure copper (zinc is cheaper than copper).
Bronze: Higher cost than brass (tin is more expensive than zinc).
Copper-Nickel: Highest cost (nickel is a premium metal)-used only in high-performance applications where corrosion resistance is critical.
7. Application Scenarios
Electrical: Wires, cables, busbars, transformers, and circuit boards (high conductivity).
Thermal: Heat exchangers, radiators, and cooling systems (high thermal conductivity).
Plumbing: Pipes and fittings (corrosion resistance in fresh water).
Electronics: Semiconductor components (oxygen-free copper to avoid contamination).
Brass: Decorative items (door handles, faucets), musical instruments, ammunition casings, and plumbing fixtures (balance of cost, formability, and corrosion resistance).
Bronze: Bearings, bushings, gears, marine propellers, and architectural hardware (high strength, wear resistance, and seawater corrosion resistance).
Copper-Nickel: Ship hulls, heat exchangers, desalination plants, and offshore oil platforms (extreme corrosion resistance in seawater).
Aluminum Bronze: Industrial valves, pumps, and mining equipment (resistance to abrasion and harsh chemicals).
