Difference Between Copper, Brass and Bronze


Copper, Brass and Bronze, or the “Red Metals,” may look the same initially but are quite different.

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Copper

Copper is used in various products due to its excellent electrical and thermal conductivity, strength, formability, and corrosion resistance. Pipe and pipe fittings are commonly manufactured from these metals due to their corrosion resistance. They can be readily soldered and brazed, and many can be welded by various gas, arc, and resistance methods. They can be polished and buffed to almost any desired texture and lustre.

There are grades of unalloyed Copper, and they can vary in the number of impurities that are contained. Oxygen-free copper grades are explicitly used in functions requiring high conductivity and ductility.

One of the most important properties of copper is its ability to fight bacteria. After extensive antimicrobial testing by the Environmental Protection Agency, it was found that 355 copper alloys, including many brasses, were found to kill more than 99.9% of bacteria within two hours of contact. Normal tarnishing was found not to impair antimicrobial effectiveness.

Copper Applications

Copper was one of the earliest metals discovered. The Greeks and Romans made it into tools or adornments, and there are even historical details showing the application of copper to sterilize wounds and purify drinking water. Today, it is most commonly found in electrical materials such as wiring because of its ability to conduct electricity effectively.

Brass

Brass is mainly an alloy that consists of copper with zinc added. Brasses can have varying amounts of zinc or other elements added. These variable mixtures produce a wide range of properties and variations in colour. Increased amounts of zinc provide the material with improved strength and ductility. Brass can range in colour from red to yellow, depending on the amount of zinc added to the alloy.

If the zinc content of the brass ranges from 32% to 39%, it will have increased hot-working abilities, but the cold-working will be limited.

If the brass contains over 39% zinc (for example – Muntz Metal), it will have a higher strength and lower ductility (at room temperature).

Brass Applications

Brass is commonly used for decorative purposes primarily because it resembles gold. It is also commonly used to make musical instruments due to its high workability and durability.

Other Brass Alloys

Tin Brass

This is an alloy that contains copper, zinc, and tin. This alloy group would include admiralty brass, naval brass, and free-machining brass. The tin has been added to inhibit dezincification (the leaching of zinc from brass alloys) in many environments. This group has low sensitivity to dezincification, moderate strength, high atmospheric and aqueous corrosion resistance, and excellent electrical conductivity. They possess good hot forgeability and good cold formability. These alloys are typically used to make fasteners, marine hardware, screw machine parts, pump shafts and corrosion-resistant mechanical products.

Bronze

Bronze is an alloy that consists primarily of copper with the addition of other ingredients. In most cases, the ingredient added is typically tin, but arsenic, phosphorus, aluminum, manganese, and silicon can also be used to produce different properties in the material. All these ingredients produce an alloy much harder than copper alone.

Bronze is characterized by its dull gold colour. You can also tell the difference between bronze and brass because bronze will have faint rings on its surface.

Bronze Applications

Bronze is used in the construction of sculptures, musical instruments and medals, and industrial applications such as bushings and bearings, where its low metal-on-metal friction is an advantage. Bronze also has nautical applications because of its corrosion resistance.

Other Bronze Alloys

Phosphor Bronze (or Tin Bronze)

This alloy typically has a tin content ranging from 0.5% to 1.0% and a phosphorous range of 0.01% to 0.35%. These alloys are notable for their toughness, strength, low coefficient of friction, high fatigue resistance, and fine grain. The tin content increases the corrosion resistance and tensile strength, while the phosphorous content increases the wear resistance and stiffness. Some typical end uses for this product would be electrical products, bellows, springs, washers, and corrosion-resistant equipment.

Aluminum Bronze

This has an aluminum content range of 6% – 12%, an iron content of 6% (max), and a nickel content of 6% (max). These combined additives provide increased strength, combined with excellent resistance to corrosion and wear. This material is commonly used to manufacture marine hardware, sleeve bearings and pumps or valves that handle corrosive fluids.

Silicon Bronze

This alloy can cover both brass and bronze (red silicon brasses and red silicon bronzes). They typically contain 20% zinc and 6% silicon. Red brass has high strength and corrosion resistance and is commonly used for valve stems. Red bronze is very similar, but it has lower concentrations of zinc. It is commonly used in the manufacturing of pump and valve components.

Nickel Brass (or Nickel Silver)

This is an alloy that contains copper, nickel, and zinc. The nickel gives the material an almost silver appearance. This material has moderate strength and relatively good corrosion resistance. This material is typically used to make musical instruments, food and beverage equipment, optical equipment, and other items where aesthetics are important.

Copper Nickel (or Cupronickel)

This alloy can contain anywhere from 2% to 30% nickel. This material has a very high corrosion resistance and has thermal stability. This material also exhibits a very high tolerance to corrosion cracking under stress and oxidation in a steam or moist air environment. Higher nickel content in this material will have improved corrosion resistance in seawater and resistance to marine biological fouling. This material is typically used in making electronic products, marine equipment, valves, pumps and ship hulls.

Video Update

Don’t have time to read the blog? You can check out our video below to find out the difference between copper, brass and bronze:

Which is more expensive, brass, bronze, or copper?

While it can vary depending on which grades you are comparing, copper is typically the most expensive of the three red metals. While all three contain copper, the percentage is far lower in Brass and Bronze than in pure copper as alloying elements are mixed in. This reduces the cost of brass and bronze. Bronze is usually more expensive than brass, partly due to the processes required to manufacture bronze.

Which lasts longer, brass, bronze, or copper?

The longevity of brass, bronze, or copper largely depends on various factors, including the specific alloy composition, environmental conditions, and the intended use of the metal. Generally, brass has good corrosion resistance, making it last a long time. However, in particularly harsh or corrosive environments, brass can gradually degrade. Proper maintenance and protective coatings can extend its lifespan. Due to its resistance to moisture and corrosion, bronze often has a longer lifespan than pure copper or some brass alloys. Pure copper is highly resistant to corrosion in most environments. However, it can gradually oxidize, forming a greenish patina (verdigris).

What factors affect how long brass, bronze, and copper last?

The longevity of brass, bronze, and copper materials is influenced by several factors, including:

Composition – The specific alloy composition of brass, bronze, or copper can significantly impact their durability. Different alloys with varying proportions of copper and other metals (such as zinc in brass or tin in bronze) can exhibit different levels of corrosion resistance and mechanical strength.

Environmental Conditions – The surrounding environment plays a crucial role in the longevity of these metals. Factors like humidity, temperature, pollution levels, exposure to saltwater, and chemical contaminants can affect corrosion rates. For example, marine environments with saltwater exposure can accelerate corrosion.

Exposure to Moisture – Moisture is a key contributor to corrosion. Prolonged exposure to moisture or high humidity levels can lead to corrosion in these metals, especially in the presence of oxygen and certain chemicals.

Mechanical Stress – Mechanical stress, such as vibration, bending, or impact, can affect the longevity of these materials. Stress can lead to microcracks or wear, which can facilitate corrosion.

pH Levels – The pH level of the surrounding environment can influence corrosion rates. Highly acidic or alkaline conditions may increase the susceptibility of these metals to corrosion.

Maintenance – Regular maintenance practices, such as cleaning, protective coatings, and lubrication, can extend the lifespan of brass, bronze, or copper materials. Removing contaminants and applying appropriate coatings can help prevent corrosion.

Exposure to Chemicals – Exposure to chemicals, including acids, alkalis, and industrial pollutants, can affect the corrosion resistance of these metals. Compatibility with specific chemicals should be considered in applications involving exposure to such substances.

Design and Installation – The design and installation of components made from these metals can impact their durability. Proper design, material selection, and installation techniques can reduce stress, prevent water accumulation, and improve longevity.

Operating Temperature – Extreme temperatures can affect the mechanical properties and corrosion resistance of these materials. Some alloys may perform better at elevated temperatures than others.

Frequency of Use – Frequent usage and wear and tear can impact the lifespan of components made from these metals, particularly in moving parts or high-stress applications.

Coatings and Surface Treatments – Applying protective coatings or surface treatments, such as galvanization or anodization, can enhance the corrosion resistance of these metals and extend their lifespan.

How do you tell bronze from brass?

Distinguishing between bronze and brass can sometimes be challenging because they share similar appearances, primarily a yellowish or reddish-gold colour. However, there are a few methods to differentiate the two:

Composition – The most reliable way to distinguish bronze from brass is to understand their compositions. Bronze is primarily composed of copper and tin, although it can contain other elements. The tin content in bronze typically ranges from 5% to 12%. Brass is primarily composed of copper and zinc, with various proportions of zinc. Brass can have a wide range of zinc content, from less than 10% to over 40%, depending on the specific alloy.

Color – While both metals have a golden appearance, bronze often has a slightly reddish or pinkish hue compared to the more yellowish colour of brass. However, colour alone may not always be a definitive indicator due to variations in alloy compositions.

Density – Bronze is generally denser than brass. If you have two objects of the same size, the bronze object will typically feel heavier.

Magnetism – Brass is not magnetic, while some bronze alloys can exhibit weak magnetic properties due to the presence of iron or other magnetic elements. However, this method may not always be conclusive, as not all bronze alloys are magnetic.

Sound – When struck, bronze produces a lower-pitched and more resonant sound than brass, which has a higher-pitched sound.

Laboratory Analysis – In some cases, especially when dealing with antique or valuable objects, laboratory analysis can determine the precise composition of the metal, confirming whether it is bronze or brass.


Metal Supermarkets

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At Metal Supermarkets, we supply a wide range of metals for a variety of applications. Our stock includes: mild steel, stainless steel, aluminum, tool steel, alloy steel, brass, bronze and copper.

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