Bronze

WHAT IS BRONZE?

Bronze is an alloy made from copper and another metal, usually tin. Bronze is one of the earliest metals used by man. Most modern bronze contains 88 percent copper and 12 percent tin. Bronze may also contain manganese, nickel, aluminum, phosphorus, silicon, zinc, or arsenic.

Bronze shares similarities with brass and is sometimes considered a type of brass. Both are defined according to their element composition. At one time, bronze was defined as an alloy consisting of copper with tin, while brass was an alloy made from copper with zinc.

Properties

Golden, hard and brittle (less brittle than cast iron)
Highly ductile
Highly elastic
Low friction against other metals
Lower melting point than iron or steel
More accessible to produce than iron or steel
Expands slightly when solidifying, allowing it to fill molds
Better heat and electricity conductivity than most steels
Won’t spark when struck against a hard surface
Can be used around flammable and explosive materials
Superficial oxidization (generally)

TYPES OF BRONZE

Silicon Bronze (Red Silicon Bronze)

Silicon bronze, also known as red silicon bronze, contains copper, up to 6 percent silicon, and zinc. Silicon bronze can also contain other alloys such as iron, tin, manganese, and zinc.

Properties

High strength
Easy to pour
High corrosion resistance
Appealing surface finish

Phosphor Bronze (Tin Bronze)

Phosphor bronze, or tin bronze, contains copper, tin content up to 11 percent, and phosphorus up to 0.35 percent. Phosphorus increases the wear resistance and stiffness of phosphor bronze.

Properties

Tough
Durable
Low friction coefficient
Fine grain

Aluminum Bronze

Aluminum bronze contains copper and 6 percent to 12 percent aluminum. Other additions can include iron, nickel, manganese, and silicon.

Properties

High strength
Corrosion-resistant (includes saltwater corrosion)
Tarnish resistant

Manganese Bronze

Manganese bronze is made from up to 3 percent manganese, zinc, copper, iron, and aluminum.

Properties

Shock resistant
Will deform instead of breaking
Highly resistant to saltwater corrosion

Bearing Bronze

Bearing bronze offers low-friction properties thanks to its 6 percent to 8 percent lead content.

Copper-Nickel (Cupronickel)

Copper-nickel bronze, also known as cupronickel, contains a larger percentage of nickel (2 percent to 30 percent) than other types of bronze.

Properties

Durable
Corrosion-resistant (including saltwater corrosion)
High thermal stability

Bismuth Bronze

Bismuth bronze contains 1 percent to 6 percent bismuth and is sometimes used as an alternative to leaded bronze. Ceremonial Inca knives found at Machu Picchu, Peru, have blades made of bismuth bronze.

Properties