Tombac

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Ottoman tombac ewer and basin set - 1870 - Collection of Turkish and Islamic Arts Museum - Brought to museum in 1926 from the tomb of Sultana Pertevniyal Tombac ewer.JPG
Ottoman tombac ewer and basin set – 1870 – Collection of Turkish and Islamic Arts Museum – Brought to museum in 1926 from the tomb of Sultana Pertevniyal

Tombac, as it is spelled in French, or tombak, is a brass alloy with high copper content and 5–20% zinc content. [1] Tin, lead or arsenic may be added for colouration. [2] [3] 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%. [1] [4]

Contents

Etymology

The term tombak is derived from tembaga, an Indonesian/Malay word of Javanese origin meaning copper.[ citation needed ]Tembaga entered Dutch usage concurrent with their colonisation of Indonesia. Likely, the term was used generically to describe Indonesian high-copper brass items, including gamelan gongs. It is one of the very few Indonesian loan words used in English or German.

Common types

Ure notes the following forms of tombak in widespread use during the time the text was published (1856): [5]

Piggot states the brass used for machinery and locomotives in England was composed of copper 74.5%, zinc 25%, and lead 0.5%- which would make it a tombac according to Ure. [6] Piggot's own definition of tombak is problematic at best: "red brass or tombak as it is called by some, has a great preponderance of copper, from 5 ounces of zinc down to 1/2 ounce of zinc to the pound [sic: copper?]" [6]

Tempers

Typical tempers are soft annealed and rolled hard.

Applications

A "bronze" medal (actually tombac) from the 1980 Summer Olympics 1980 Summer Olympics bronze medal.JPG
A "bronze" medal (actually tombac) from the 1980 Summer Olympics

Tombac is easy and soft to work by hand: hand tools can easily punch, cut, enamel, repousse, engrave, gild, or etch it. It has a higher sheen than most brasses or copper, and does not easily tarnish. Historically, it was used by the Javanese as a faux gold finish for objects d'art and ornaments.

See also

Related Research Articles

Brass Alloy of copper and zinc

Brass is an alloy of copper and zinc, in proportions which can be varied to achieve varying mechanical and electrical properties. It is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure.

Bronze metal alloy consisting of copper and tin

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 or metalloids such as arsenic, phosphorus 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.

Metal Type of material

A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable or ductile. A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride.

Solder

Solder is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to adhere to and connect the pieces after cooling, which requires that an alloy suitable for use as solder have a lower melting point than the pieces being joined. The solder should also be resistant to oxidative and corrosive effects that would degrade the joint over time. Solder used in making electrical connections also needs to have favorable electrical characteristics.

Zinc Chemical element with atomic number 30

Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a silvery-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity (electrowinning).

Cupronickel or copper-nickel (CuNi) is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. The copper content typically varies from 60 to 90 percent.

Brazing High-temperature soldering; metal-joining technique by high-temperature molten metal filling

Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal.

Tennantite

Tennantite is a copper arsenic sulfosalt mineral with an ideal formula Cu12As4S13. Due to variable substitution of the copper by iron and zinc the formula is Cu6[Cu4(Fe,Zn)2]As4S13. It is gray-black, steel-gray, iron-gray or black in color. A closely related mineral, tetrahedrite (Cu12Sb4S13) has antimony substituting for arsenic and the two form a solid solution series. The two have very similar properties and is often difficult to distinguish between tennantite and tetrahedrite. Iron, zinc, and silver substitute up to about 15% for the copper site.

<i>Tumbaga</i> Alloy

Tumbaga is the name for a non-specific alloy of gold and copper given by Spanish Conquistadors to metals composed of these elements found in widespread use in pre-Columbian Mesoamerica in North America and South America.

Gunmetal

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. Gunmetal, which casts and machines well and is resistant to corrosion from steam and salt water, 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 to 310 MPa, a specific gravity of 8.7, a Brinell hardness of 65 to 74, and a melting point of around 1,000 degrees Celsius.

Spelter

Spelter is a zinc–lead alloy that ages to resemble bronze, but is softer and has a lower melting point. The name can also refer to a copper–zinc alloy used for brazing, or to pure zinc.

<i>Panchaloha</i>

Panchaloha, also called Pañcadhātu is a term for traditional five-metal alloys of sacred significance, used for making Hindu temple murti and jewelry.

Architectural metals

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.

Group 11 element

Group 11, by modern IUPAC numbering, is a group of chemical elements in the periodic table, consisting of copper (Cu), silver (Ag), and gold (Au). Roentgenium (Rg) is also placed in this group in the periodic table, although no chemical experiments have yet been carried out to confirm that it behaves like the heavier homologue to gold. Group 11 is also known as the coinage metals, due to their former usage. They were most likely the first three elements discovered. Copper, silver, and gold all occur naturally in elemental form.

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. Documented use of brass dates back to early Romans, and is referenced in the King James Bible. There are both positive and negative health effects that are associated with the use of this material.

Bronze and brass ornamental work

The use of bronze dates from remote antiquity. This important metal is an alloy composed of copper and tin, in proportion which vary slightly, but may be normally considered as nine parts of copper to one of tin. Other ingredients which are occasionally found are more or less accidental. The result is a metal of a rich golden brown colour, capable of being worked by casting — a process little applicable to its component parts, but peculiarly successful with bronze, the density and hardness of the metal allowing it to take any impression of a mould, however delicate. It is thus possible to create ornamental work of various kinds.

Silicon tombac is an alloy made of copper (80%), zinc (16%) and silicon (4%).

Irogane is the term for a set of Japanese metals – forms of copper, and copper alloys – treated in niiro patination processes, traditionally used in sword-making, catches for sliding doors, and luxury highlights on larger objects, and in modern times, in jewellery. The alloys contain two to five metals. Some scholars believe that methods similar to those involved in irogane production may also have been used in ancient Egypt and the Roman world, as well as China and Tibet (dzne-ksim).

References

  1. 1 2 "Archived copy". Archived from the original on 2009-09-03. Retrieved 2009-08-02.CS1 maint: discouraged parameter (link) CS1 maint: archived copy as title (link)
  2. Institute of Metals, Journal of the Institute of Metals Volume 43, Institute of Metals: 1930
  3. http://www.schlenk.de/index.php?id=519&L=1&kat=1.1.1#719
  4. Tibor Eric Robert Singer, German-English dictionary of metallurgy: with related material on ores, mining and minerals, crystallography, welding, metal-working, tools, metal products, and metal chemistry, McGraw-Hill: 1945: 298 pages
  5. Andrew Ure, A dictionary of arts, manufactures and mines: containing a clear exposition of their principles and practice Robert Hunt (ed.), D. Appleton & Co.: 1856: pp243
  6. 1 2 Aaron Snowden Piggot, The chemistry and metallurgy of copper, Lindsay and Blakiston: 1858: 388 pages: pp354, google book reference:
  7. Arméstabens taktiska avdelning februari 1962 : "Erfarenheterna från striderna i Kongo under september och december 1961"
  8. "Brass Sheet Metal Dealer on the Alloy's Use in Architectural Projects". Rotax Metals. 31 July 2014. Retrieved 14 July 2019.CS1 maint: discouraged parameter (link)