Niobium-tin

Niobium-tin (Nb₃Sn) or triniobium-tin is a metallic chemical compound of niobium (Nb) and tin (Sn), used industrially as a type II superconductor. This intermetallic compound is an A15 phase superconductor. It is more expensive than niobium-titanium (NbTi), but remains superconducting up to a magnetic flux density of 30 teslas (T), compared to a limit of roughly 15 T for NbTi.

Nb₃Sn was discovered to be a superconductor in 1954. The material's ability to support high currents and magnetic fields was discovered in 1961 and started the era of large-scale applications of superconductivity.

The critical temperature is 18.3 kelvins (K). Application temperatures are commonly around 4.2 K, the boiling point of liquid helium at atmospheric pressure.

In April 2008 a record non-copper current density was claimed of 2643 A/mm² at 12 T and 4.2 K

Practical use

Mechanically, Nb₃Sn is extremely brittle and thus can not be easily drawn into a wire, which is necessary for winding superconducting magnets. To overcome this, wire manufacturers typically draw down composite wires containing ductile precursors. The "internal tin" process includes separate alloys of Nb, Cu and Sn. The "bronze" process contains Nb in a copper-tin bronze matrix. With both processes the strand is typically drawn to final size and coiled into a solenoid or cable before heat treatment. It is only during the heat treatment that the Sn reacts with the Nb to form the brittle, superconducting niobium-tin compound. The powder-in-tube process is also used.

Tin

Tin is a chemical element with the symbol Sn (for Latin: stannum) and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows a chemical similarity to both neighboring group-14 elements, germanium and lead, and has two possible oxidation states, +2 and the slightly more stable +4. Tin is the 49th most abundant element and has, with 10 stable isotopes, the largest number of stable isotopes in the periodic table. It is a silvery, malleable other metal that is not easily oxidized in air, obtained chiefly from the mineral cassiterite where it occurs as tin dioxide, SnO₂.

The first alloy used on a large scale since 3000 BC was bronze, an alloy of tin and copper. After 600 BC, pure metallic tin was produced. Pewter, which is an alloy of 85–90% tin with the remainder commonly consisting of copper, antimony and lead, was used for flatware from the Bronze Age until the 20th century. In modern times, tin is used in many alloys, most notably tin/lead soft solders, which are typically 60% or more tin. Another large application for tin is corrosion-resistant tin plating of steel. Because of its low toxicity, tin-plated metal was used for food packaging as tin cans, which are now made mostly of steel, even though the name is kept in English.

Tin box

A tin box is a tinplate container. Tinplate metal is primarily steel with a very thin tin coating. Tin-free steel is also used. In some cultures, these boxes or cans are referred to as "tin boxes" or sometimes even "tins". Many “tin boxes” have hinged or removable lids or covers. Some people collect tin boxes as a hobby.

Cans

These tinplate cans are often used to package breath mints, throat lozenges, instant coffee, biscuits and holiday treats. Highly decorated "holiday tins" are sold during the holiday season and are popular gifts, and often contain cookies, candy, or popcorn. Similar festive containers are used in Europe for sweets, biscuits, cakes and chocolates, mainly during Christmas, rather than in the summer holidays and in countries with British associations, they are usually called "biscuit tins". In Denmark, butter cookies in tins are produced and sold there, and are also exported to other countries. These types of smaller tin boxes are sometimes reused to store items, or to create kits, such as a survival kit. A hobby involves modifying tin boxes with decorations and embellishments.

Tin (disambiguation)

Tin is a chemical element.

Tin may also refer to:

See also