C1100 Copper Alloy
C1100 copper alloy, also known as electrolytic tough pitch copper (ETP copper), is one of the most widely used pure copper alloys in industrial applications. It is valued for its excellent electrical conductivity, thermal conductivity, and malleability, making it a staple in electrical, automotive, and manufacturing industries. Below is a detailed overview of its key characteristics, properties, applications, and related information.
### Chemical Composition
C1100 copper is classified as a “high-purity” copper alloy, with copper content being its primary component. Its typical chemical composition is as follows:
Copper (Cu): ≥99.90% (the main element, ensuring high conductivity and purity).
Oxygen (O): 0.02%–0.04% (introduced during the smelting process to remove impurities like phosphorus, arsenic, and antimony; hence the name “tough pitch”).
Other impurities: ≤0.10% (including trace elements such as iron, lead, nickel, and sulfur, which are strictly controlled to avoid affecting performance).
### Physical and Mechanical Properties
C1100 copper exhibits a unique combination of physical and mechanical properties that make it versatile across industries:
Physical Properties
Density: Approximately 8.94 g/cm³ (similar to pure copper, ensuring good structural stability).
Melting point: Around 1083°C (consistent with pure copper, suitable for high-temperature processing).
Electrical conductivity: ≥97% IACS (International Annealed Copper Standard) at 20°C (one of the highest among commercial metals, critical for electrical applications).
Thermal conductivity: About 391 W/(m·K) (excellent heat transfer capability, used in heat exchangers and cooling systems).
Electrical resistivity: ≤1.72 μΩ·cm (low resistance, minimizing energy loss in electrical circuits).
Mechanical Properties (Annealed Condition)
Tensile strength: 220–260 MPa (moderate strength, balancing formability and structural integrity).
Yield strength: 60–100 MPa (low yield strength, indicating good ductility).
Elongation: ≥35% (high ductility, allowing for complex forming processes like bending, drawing, and stamping).
Hardness: ≤45 HB (Brinell hardness, soft and easy to machine in annealed state).
Note: Mechanical properties can vary with processing methods (e.g., cold working increases strength but reduces ductility).
### Processing and Fabrication
C1100 copper is highly workable, supporting a range of fabrication techniques:
Annealing: Heat treatment at 400–600°C relieves internal stress and restores ductility after cold working.
Cold working: Rolling, drawing, or stamping increases strength (e.g., cold-rolled sheets have higher tensile strength than annealed ones).
Welding: Can be welded using methods like gas tungsten arc welding (GTAW) and resistance welding, but oxygen in the alloy may cause embrittlement if not properly handled.
Machining: Relatively easy to machine in annealed form, though it may require lubrication to prevent surface damage.
### Corrosion Resistance
C1100 copper offers moderate corrosion resistance in most environments:
Resists atmospheric corrosion, forming a protective patina (greenish layer) over time, which inhibits further oxidation.
Performs well in fresh water but may corrode in acidic or alkaline solutions, especially in the presence of sulfides or ammonia.
Limitations: Susceptible to “hydrogen embrittlement” in high-temperature hydrogen environments, where hydrogen reacts with oxygen to form water vapor, causing internal cracks.
### Applications
Due to its superior conductivity and formability, C1100 copper is used in numerous industries:
Electrical industry: Electrical wires, cables, busbars, connectors, and transformer windings (leveraging high electrical conductivity).
Thermal management: Heat sinks, radiators, heat exchangers, and cooling coils (excellent thermal conductivity).
Construction: Plumbing pipes, roofing sheets, and decorative elements (corrosion resistance and malleability).
Automotive: Battery cables, wiring harnesses, and heat exchangers.
Manufacturing: Springs, gaskets, and electrical contacts (formability and low resistivity).
### Standards and Specifications
C1100 copper is defined by various international standards, ensuring consistency in quality:
ASTM B152: Standard for copper sheet, strip, plate, and rolled bar.
ASTM B188: Standard for copper tube for general purposes.
JIS H3100: Japanese Industrial Standard for copper and copper alloys (C1100 is equivalent to JIS C1100).
EN 1976: European standard for copper and copper alloys (designated as CW004A).
### Advantages and Disadvantages
Advantages
Exceptional electrical and thermal conductivity.
High ductility and formability for complex fabrication.
Good corrosion resistance in mild environments.
Cost-effective compared to high-alloyed copper materials.
Disadvantages
Lower strength compared to copper alloys like brass or bronze.
Susceptible to hydrogen embrittlement in specific environments.
Poor resistance to strong acids, alkalis, or sulfide-containing solutions.
### Similar Alloys
C10200 (Oxygen-Free Electronic Copper): Higher purity (99.99% Cu) with lower oxygen content, used in ultra-high-conductivity applications (e.g., superconductors).
C12200 (Phosphorus-Deoxidized Copper): Deoxidized with phosphorus, reducing oxygen-related embrittlement, suitable for welding and brazing.
Brass (Cu-Zn alloys): Higher strength but lower conductivity than C1100, used for structural components.
In summary, C1100 copper alloy is a reliable choice for applications demanding high conductivity, formability, and moderate corrosion resistance. Its balance of properties and cost-effectiveness make it indispensable in electrical, thermal, and manufacturing sectors.