An alloy is a mixture of chemical elements of which in most cases at least one is a metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Most alloys are metallic and show good electrical conductivity, ductility, opacity, and luster, and may have properties that differ from those of the pure elements such as increased strength or hardness. In some cases, an alloy may reduce the overall cost of the material while preserving important properties. In other cases, the mixture imparts synergistic properties such as corrosion resistance or mechanical strength.
Brass is an alloy of copper and zinc, in proportions which can be varied to achieve different colours and mechanical, electrical, acoustic and chemical properties, but copper typically has the larger proportion, generally 66% copper and 34% zinc. In use since prehistoric times, it is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure.
Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals and sometimes non-metals, such as phosphorus, or metalloids, such as arsenic or silicon. These additions produce a range of alloys that may be harder than copper alone, or have other useful properties, such as strength, ductility, or machinability.
Cupronickel or copper–nickel (CuNi) is an alloy of copper with nickel, usually along with small quantities of other elements added for strength, such as iron and manganese. The copper content typically varies from 60 to 90 percent.
Nickel silver, maillechort, German silver, argentan, new silver, nickel brass, albata, or alpacca is a copper alloy with nickel, and often zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver does not contain the element silver. It is named for its silvery appearance, which can make it attractive as a cheaper and more durable substitute. It is also well suited for being plated with silver.
Brazing is a metal-joining process in which two or more metal items are joined by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal.
Phosphor bronze is a member of the family of copper alloys. It is composed of copper that is alloyed with 0.5–11% of tin and 0.01–0.35% phosphorus, and may contain other elements to confer specific properties. The tin increases the corrosion resistance and strength of the alloy, while the phosphorus increases its wear resistance and stiffness.
Tombac, or tombak, is a brass alloy with high copper content and 5–20% zinc content. Tin, lead or arsenic may be added for colouration. It is a cheap malleable alloy mainly used for medals, ornament, decoration and some munitions. In older use, the term may apply to brass alloy with a zinc content as high as 28–35%.
Plating is a finishing process in which a metal is deposited on a surface. Plating has been done for hundreds of years; it is also critical for modern technology. Plating is used to decorate objects, for corrosion inhibition, to improve solderability, to harden, to improve wearability, to reduce friction, to improve paint adhesion, to alter conductivity, to improve IR reflectivity, for radiation shielding, and for other purposes. Jewelry typically uses plating to give a silver or gold finish.
Gun metal, also known as red brass in the United States, is a type of bronze – an alloy of copper, tin, and zinc. Proportions vary but 88% copper, 8–10% tin, and 2–4% zinc is an approximation. Originally used chiefly for making guns, it has largely been replaced by steel for that purpose. Gunmetal casts and machines well, and is resistant to corrosion from steam and salt water. It is used to make steam and hydraulic castings, valves, gears, statues, and various small objects, such as buttons. It has a tensile strength of 221 megapascals (32,100 psi) to 310 megapascals (45,000 psi), a specific gravity of 8.7, a Brinell hardness of 65 to 74, and a melting point of around 1,000 degrees Celsius.
Aluminium bronze is a type of bronze in which aluminium is the main alloying metal added to copper, in contrast to standard bronze or brass. A variety of aluminium bronzes of differing compositions have found industrial use, with most ranging from 5% to 11% aluminium by weight, the remaining mass being copper; other alloying agents such as iron, nickel, manganese, and silicon are also sometimes added to aluminium bronzes.
Metals used for architectural purposes include lead, for water pipes, roofing, and windows; tin, formed into tinplate; zinc, copper and aluminium, in a range of applications including roofing and decoration; and iron, which has structural and other uses in the form of cast iron or wrought iron, or made into steel. Metal alloys used in building include bronze ; brass ; monel metal and nickel silver, mainly consisting of nickel and copper; and stainless steel, with important components of nickel and chromium.
Colored gold is the name given to any gold that has been treated using techniques to change its natural color. Pure gold is slightly reddish yellow in color, but colored gold can come in a variety of different colors by alloying it with different elements.
The coinage metals comprise those metallic chemical elements and alloys which have been used to mint coins. Historically, most coinage metals are from the three nonradioactive members of group 11 of the periodic table: copper, silver and gold. Copper is usually augmented with tin or other metals to form bronze. Gold, silver and bronze or copper were the principal coinage metals of the ancient world, the medieval period and into the late modern period when the diversity of coinage metals increased. Coins are often made from more than one metal, either using alloys, coatings (cladding/plating) or bimetallic configurations. While coins are primarily made from metal, some non-metallic materials have also been used.
C41100 Lubaloy is a wrought copper alloy that is composed mainly of copper and zinc. Lubaloy possesses many favorable characteristics making it, and other types of brass, a popular choice in manufacturing. It is a source material in many processes including the creation of electrical components and bullet-making. There are both positive and negative health effects that are associated with the use of this material.
Copper alloys are important netting materials in aquaculture. Various other materials including nylon, polyester, polypropylene, polyethylene, plastic-coated welded wire, rubber, patented twine products, and galvanized steel are also used for netting in aquaculture fish enclosures around the world. All of these materials are selected for a variety of reasons, including design feasibility, material strength, cost, and corrosion resistance.
Materials for use in vacuum are materials that show very low rates of outgassing in vacuum and, where applicable, are tolerant to bake-out temperatures. The requirements grow increasingly stringent with the desired degree of vacuum to be achieved in the vacuum chamber. The materials can produce gas by several mechanisms. Molecules of gases and water can be adsorbed on the material surface. Materials may sublimate in vacuum. Or the gases can be released from porous materials or from cracks and crevices. Traces of lubricants, residues from machining, can be present on the surfaces. A specific risk is outgassing of solvents absorbed in plastics after cleaning.
Copper has earned a respected place in the related fields of architecture, building construction, and interior design. From cathedrals to castles and from homes to offices, copper is used for a variety of architectural elements, including roofs, flashings, gutters, downspouts, domes, spires, vaults, wall cladding, and building expansion joints.
Aluminium brass is a technically rather uncommon term for high-strength and partly seawater-resistant copper-zinc cast and wrought alloys with 55–66% copper, up to 7% aluminium, up to 4.5% iron, and 5% manganese. Aluminium bronze is technically correct as bronze, a zinc-free copper-tin casting alloy with aluminium content.
