More than just a shiny reddish-orange metal, copper is a beacon of human progress. The use of copper in ancient tools to wires in a smartphone showcases its properties. As far as modern manufacturing materials go, this one has an interesting history as one of the most important materials in the world.
In this blog post, we will discuss what copper is, its history, its production, and its properties.
What is copper?
Copper is an element on the periodic table of elements with the chemical symbol of Cu and an atomic number of 29. It is a member of the transition metals, which means it has a partially filled d-orbital. It can form ions with an incomplete d-subshell. This ability is why Cu is an excellent conductor of heat and electricity and why applications such as cookware and busbars use it. Its atomic structure and properties make it a valuable material.
What is the history of copper?
Copper has been an important material throughout history and across every civilization. Historians and anthropologists have noted its use as early as 8,000-5,000 BC; for example, hammered copper beads and tools have been found at sites in Turkey and Iraq.
Ancient mines in Serbia, Bulgaria, and the Great Lakes region of North America show evidence of copper extraction as early as 4000 BC, with the earliest copper smelting around 5,550-5,000 BC. Smelting enabled metallurgists to begin casting and alloying copper, thereby creating bronze by adding tin, arsenic, and other metals.
Ancient peoples worldwide traded copper and bronze across cultures and continents, fostering economic and cultural connections.
Today, copper is vital to many industries, including electronics and construction. Its applications range from wiring to semiconductors and circuit boards to EV batteries. Did you know an EV uses up to six times the amount of copper as a vehicle with a combustion engine?
Renewable energy is driving demand for copper. It is one material that won’t be falling out of use any time soon!
How is copper made?
Step by step, the process of creating manufacturable copper begins with mining ore, grinding it, concentrating it, and smelting it.
- Mining and Crushing: Using open-pit or underground mining methods brings copper ore to the surface. The large rocks are crushed into smaller pieces and then ground into sand.
- Concentration: Water and chemicals mix with the powdered ore. Next, blowing air into the mixture causes copper minerals to attach to the bubbles and rise to the surface as a froth.
- Smelting: Skimming the copper-rich froth off the surface means the concentrated Cu is ready for the smelting step. A high-temperature furnace further melts the material, separating molten Cu from impurities such as iron and sulfur, which form a slag. This stage results in a product called blister copper.
- Conversion: Further refining the blister copper removes the remaining impurities, resulting in 98-99% pure copper.
- Electrolytic Refining: To obtain Cu with over 99.99% purity, casting impure Cu into large slabs called anodes. Next, place the anodes into an electrolytic cell containing an electrolyte and a pure copper cathode plate. An electric current causes pure copper to deposit on the cathode plate, leaving impurities behind.
What are the properties of Cu?
Copper is a valuable material with excellent heat and electrical conductivity, high malleability and ductility, corrosion resistance, and antimicrobial properties.
- What color is copper? Shiny reddish-brown in color. Pure Cu is pink before oxidation, but a brown copper oxide forms quite fast. It can also have a green tarnish.
- Ductility and Malleability: It is easily stretched into thin wires or hammered into thin sheets without fracturing.
- Elasticity: With a Young’s Modulus of about 110 to 130 GPa, it is far less stiff than steel and can easily deform.
- Strength: Possessing good tensile and shear strength when cold-rolled. Copper is not as strong as its alloys, such as brass.
- Toughness: It does not become brittle at low temperatures, unlike other metals.
- Corrosion Resistant: It is resistant to corrosion and rust.
- Non-Magnetic: As a non-ferrous metal, it is non-magnetic.
- High Conductivity: Of both electricity and heat.
- Machinability: Cu has a “good machinability” rating.
According to AZO Materials:
| Property | Minimum Value (S.I.) | Maximum Value (S.I.) |
|---|---|---|
|
Atomic Volume (Average) |
0.0071 |
0.0073 |
|
Density |
8.93 |
8.94 |
|
Energy Content |
100 |
130 |
|
Bulk Modulus |
130 |
145 |
|
Compressive Strength |
45 |
330 |
|
Ductility |
0.04 |
0.5 |
|
Elastic Limit |
45 |
330 |
|
Endurance Limit |
70 |
140 |
|
Fracture Toughness |
40 |
100 |
|
Hardness |
400 |
1150 |
|
Loss Coefficient |
3.5e-005 |
0.002 |
|
Modulus of Rupture |
45 |
330 |
|
Poisson’s Ratio |
0.34 |
0.35 |
|
Shear Modulus |
44 |
49 |
|
Tensile Strength |
210 |
390 |
|
Young’s Modulus |
121 |
133 |
|
Latent Heat of Fusion |
200 |
210 |
|
Maximum Service Temperature |
350 |
400 |
|
Melting Point |
1320 |
1355 |
|
Minimum Service Temperature |
0 |
0 |
|
Specific Heat |
372 |
388 |
|
Thermal Conductivity |
147 |
370 |
|
Thermal Expansion |
16.8 |
17.9 |
|
Resistivity |
1.82 |
4.9 |
| Environmental Properties | Resistance Factors (1 = Poor, 5 = Excellent) |
|---|---|
|
Flammability |
5 |
|
Fresh Water |
5 |
|
Organic Solvents |
5 |
|
Oxidation at 500C |
3 |
|
Sea Water |
5 |
|
Strong Acid |
2 |
|
Strong Alkalis |
5 |
|
UV |
5 |
|
Wear |
5 |
|
Weak Acid |
4 |
|
Weak Alkalis |
5 |
Copper Designations
Copper has designation systems that are not specifications but rather methods for identifying chemical compositions. Property requirements are covered in ASTM, government, and military standards for each composition.
The UNS (Unified Numbering System for Metals and Alloys) designations are summarized below:
| UNS Numbers | Types | Alloy Names |
|---|---|---|
|
C10000-C19999 |
Wrought |
Coppers and High-Copper Alloys |
|
C20000-C49999 |
Wrought |
Brasses |
|
C50000 -C59999 |
Wrought |
Phosphor Bronzes |
|
C60600-C64200 |
Wrought |
Aluminum Bronzes |
|
C64700-C66100 |
Wrought |
Silicon Bronzes |
|
C66400-C69800 |
Wrought |
Brasses |
|
C70000-C79999 |
Wrought |
Copper Nickels and Nickel Silvers |
|
C80000-C82800 |
Cast |
Coppers and High-Copper Alloys |
|
C83300-C85800 |
Cast |
Brasses |
|
C86100-C86800 |
Cast |
Manganese Bronzes |
|
C87200-C87900 |
Cast |
Silicon Bronzes and Brasses |
|
C90200-C94800 |
Cast |
Tin Bronzes |
|
C95200-C95800 |
Cast |
Aluminum Bronzes |
|
C96200-C97800 |
Cast |
Copper Nickels and Nickel Silvers |
|
C98200-C98800
|
Cast |
Leaded Copper |
|
C99300-C99750 |
Cast |
Special Alloys |
- Wrought Copper Alloys: Manufacturing methods include annealing, cold working, hardening by heat treatments, or stress relieving.
- Cast Copper Alloys: Manufacturing by casting. They have a greater range of alloying elements than wrought alloys.
What industries use copper and in what applications?
Cu’s numerous properties make it an excellent choice for applications across a myriad of industries. The following are just a few examples:
- Electrical and Electronics: Wiring, cables, circuit boards, motors, transformers, and semiconductors.
- Energy: Wind turbines, generators, and solar panels.
- Construction: Plumbing, roofing, and architectural details.
- Automotive: Wiring radiators, motors, brakes, and connectors.
- Marine: Propellers, fittings, and desalination plants.
- Railways: Motors, brakes, and signaling systems.
- Industrial and Chemical Processing: Heat exchangers, condensers, pumps, valves, and containers.
- Medical: Antimicrobial surfaces, surgical tools, implants, and radiotherapy equipment.
- HVAC: Radiators, heat exchangers, and refrigeration coils.
- Consumer Goods: Cookware, sinks, door hardware, and decorative items.
FAQs
Define: Copper
It is a versatile metal known for its excellent conductivity and durability.
Is copper magnetic?
It is not magnetic; it is a non-magnetic metal.
How is copper polished?
It is polished through careful buffing and cleaning, which helps preserve its longevity by removing tarnish and oxidation that can build up over time.
