Does Brass Rust?

Brass is an alloy consisting primarily of about 60% copper and 40% zinc. It is often described as gold-like in appearance. It is a luxurious metal known for its decorative and architectural design capabilities. With its bright and shiny qualities, brass is quite popular and is cheaper than gold. Knowing that brass is an alloy of copper and zinc, it is fairly hard and does not rust easily.

We mentioned that brass is hard, but it’s still softer than bronze, which is an alloy of copper and tin. This relative softness makes brass easier to cut, shape, and file.

With the basics of brass covered, let’s settle the “rust” debate thoroughly.

Does Brass Rust

Composition and Properties of Brass

  • The proportions of copper to zinc in brass could be adjusted, changing its characteristics like color and mechanical properties.
  • Brass has a golden color that can shift to a silvery hue with increasing zinc content. Its density is approximately 8.4 to 8.73 g/cm³ and is valued for its malleability.
  • Brass is a substitutional alloy, allowing copper and zinc atoms to replace each other within the crystal structure, increasing its versatility for various applications.
  • The typical brass composition consists of approximately two-thirds copper, one-third zinc, and small amounts of other elements that can affect its susceptibility to corrosion.
PropertyValue
Chemical SymbolCu
Atomic Number29
Atomic Mass63.546 u
Density8.96 g/cm3
Hardness3.0–4.0 (Mohs hardness)
Melting Point1,984 °F (1,085 °C)
Boiling Point4,644 °F (2,562 °C)
Electrical Conductivity59.6 × 10^6 S/m
Thermal Conductivity401 W/(m·K)
ColorReddish to orange
DuctilityExcellent, easily machinable
Corrosion ResistanceGood, especially in dry environments; sensitive to acids and chlorides
Magnetic PropertiesNon-magnetic (may exhibit weak magnetism under certain conditions)

Does Brass Rust?

Brass does not rust. Rust is a type of corrosion that occurs with iron and its alloys, like steel, when they are exposed to oxygen and moisture. This process produces iron oxide, commonly known as rust, which is reddish-brown and flaky. Because brass doesn’t contain iron, it cannot rust in the traditional sense.

Does Brass Turn Green?

Brass can develop a green color over time due to a process known as “patination.” This color change occurs as the brass reacts with environmental factors such as moisture, air, and pollutants. The green coloration results from the formation of copper salts, primarily copper carbonate. This develops as the copper in the brass alloy reacts with carbon dioxide and moisture in the air.

Does Brass Rust in Salt Water?

Brass does not rust in salt water, as rust refers explicitly to the corrosion of iron and its alloys. Nevertheless, brass is susceptible to a type of corrosion known as “dezincification” when exposed to salt water.

When exposed to saltwater environments, the zinc in brass can be leached out, leaving behind a porous, weakened copper structure. This process can observably degrade the material over time. The presence of chlorides in saltwater expedites this type of corrosion.

Corrosion Resistance of Brass

While brass does not rust, it is not entirely immune to all forms of corrosion. But it boasts impressive corrosion resistance, particularly against water and other mild environments. Here are the reasons:

  1. Copper’s Natural Properties: Copper, which constitutes a significant portion of brass, naturally resists corrosion. When exposed to those elements, copper makes a protective layer of patina (a greenish film) that shields the underlying metal from further damage.
  2. Zinc’s Role: Zinc, as the other primary component, also contributes to the corrosion resistance of brass. Zinc corrodes at a slower rate and helps protect the copper from fiercer forms of corrosion.

Factors Influencing Brass Corrosion

  • Exposure to environmental factors such as moisture, chlorides, acetates, ammonia, and certain acids can cause brass to corrode.
  • The corrosion process of brass is affected by the chemical composition of the environment, as well as physical wear and contact with other metals.
  • Adjusting the alloying elements of brass, such as dezincification, can improve its resistance to corrosion.
  • Producing dezincification-resistant brass involves adjusting the zinc content or adding inhibitors such as arsenic, tin, nickel, aluminum, and phosphorus.
  • The resistance of brass parts to dezincification also depends on their manufacturing processes, including forging and annealing methods.

Applications of Brass due to Rust Resistant Properties

Plumbing Accessories

Due to its corrosion resistance, brass is utilized to make marine hardware such as fasteners, plumbing fixtures, water pumps, and pipes in marine and plumbing.

Electrical Connectors

Brass is ideal for electrical connectors, terminals, and sockets due to its good conductivity and resistance to oxidation, ensuring long-lasting electrical performance and mechanical durability. It is also suitable for electrical pin connectors and switch components.

Musical Instruments

Musical instruments such as tubas, trombones, trumpets, and French horns are crafted from brass because of its exceptional acoustic and workability properties.

Automotive Parts

In the automotive industry, brass is utilized for automotive radiators and heaters due to its excellent thermal conductivity and resistance to corrosion from coolant fluids.

Rust Resistant Coins

Several coins are often made from brass due to their resistance to tarnishing, durability, and ease of stamping.

Decorations in Architectural Structures

Brass is perfect for decorative and architectural purposes. It can be used to enhance ornamental pieces such as railings, lamps, and door handles. It is also valuable in architectural hardware for fittings that require aesthetic appeal and durability.

Weapons

Non-sparking tools used in explosive environments, such as chemical manufacturing, are typically made from brass.

Brass is commonly used for ammunition casings because it does not rust, is easy to work with, and is resistant to corrosion.

Bearings and Bushings

Brass is required in manufacturing industries for bearings and bushings, which provide low friction and resistance to wear and corrosion. Brass is also used to produce gloves for operation in corrosive environments.

Maintenance Tips for Brass

In order to maintain the appearance and performance of brass, it is essential to perform regular maintenance.

  1. Regular Cleaning
  • To clean brass regularly, use a soft sponge or cloth with a compound of mild soap and warm water. Gently wipe the brass surface to clean away dirt and grime. Next, rinse with clean water and fully dry by utilizing a soft cloth to avoid water spots.
  • For stubborn tarnish, use a commercial brass cleaner following the manufacturer’s instructions. Always test in a small area first.
  1. Avoid Harsh Chemicals
  • Avoid using scrubbing pads or abrasive cleaners as they can scratch the brass surface and destroy its finish.
  • Avoid harsh chemicals and solvents that can wipe off the protective patina or lacquer. Choose products specifically designed for brass care.
  1. Polishing
  • To bring back the shine and eliminate tarnish, use brass polish. Carry out the polish with a soft cloth, following the product’s directions. After polishing, remove any residue and buff the surface for a high shine.
  • A paste made of lemon juice and baking soda or vinegar and salt can be used to polish brass. Apply the paste gently, then rinse thoroughly.
  1. Protective Coating
  • A clear lacquer or protective coating can help prevent tarnishing and corrosion, especially for brass items exposed to moisture or heavy use. It is important to follow the application instructions for optimal results.
  • Keep in mind that protective coatings may wear off over time, so reapply as needed to maintain the brass’s appearance.
  1. Store Properly
  • Store brass items in a dry place to avoid moisture formation, which can lead to tarnishing and corrosion.
  • For items not in regular use, consider wrapping them with soft cloth or using storage cases to protect them from dust and environmental aspects.
  1. Addressing Corrosion
  • Regularly inspect for corrosion or tarnishing. Addressing issues early can prevent great damage.
  • If you notice corrosion, use a brass cleaner designed to remove it. In severe cases, professional help may be necessary to restore the item.

Summary

In summary, Brass does not rust because it does not contain iron. Iron reacts with water and moisture to form iron oxide, which is rust. Brass contains zinc and copper, which do not rust.