Nickel silver
Nickel silver is the name for a copper-nickel-zinc alloy with high corrosion resistance, strength and a silver-like appearance. Nickel silver is used in particular for table utensils ( cutlery , service cutlery and body ware ), musical instruments ( flute , trumpet , oboe ), fittings and jewelry.
For nickel silver there are also the names Alpaka / Alpacca , Argentan , Minargent , the French names Cuivre blanc and Maillechort as well as the Chinese name Packfong . The term hotel silver is also used. In Spanish , nickel silver is also known as plata alemana and in English as German silver (both German silver ) and nickel silver . Electroplated silver-plated nickel silver is called Chinese silver or alsenid designated.
properties
Nickel silver is a silver-white to yellow shiny alloy made of 47–64% copper , 10–25% nickel , 15–42% zinc , possibly with admixtures of elements such as lead , tin , manganese or iron . Compared to copper, it is characterized by greater hardness and corrosion resistance because of its nickel content . The official identification mark is the weight stamp.
- Melting point : from approx. 900 ° C , increasing depending on the alloy
- Density : 8.1 to 8.7 g cm −3 (depending on the mixture)
- Electrical conductivity : approx. 3 · 10 6 to 5 · 10 6 Ω −1 · m −1
- Thermal conductivity : approx. 25 to 35 W m −1 K −1
- Thermal expansion coefficient : 16 · 10 −6 to 17 · 10 −6 K −1
Like many copper alloys, German silver can be hardened (surface hardening) by cold forming, for example by forging , rolling or drawing . Heating ( annealing ) above approx. 500 ° C creates new metal grains (recrystallization), the material becomes soft again.
history
As early as the 17th century , the first metal goods made of an alloy called Packfong came to Europe from the Chinese Empire . But it was not until the 18th century that it was recognized that Packfong is made of copper, zinc and nickel. In the metal works of Suhl succeeded already about 1770, a similar Pakfong the alloy to produce. It soon became known as Suhler Weißkupfer . The white copper of Suhl did, however, contain arsenic and was therefore toxic.
The industrial production of copper-zinc-nickel alloys was initiated in 1823 by a competition organized by the association for the promotion of industry . The production of a white alloy was required, which looks like silver 750/000 (fine) and should also be suitable for power supplies. In addition, it should only cost 1/6 of the silver price at the time. This task was solved almost at the same time by Ernst August Geitner , who developed the alloy Argentan in Auerhammer near Aue in 1823 , and the Henniger brothers in Berlin in 1824 with the similar alloy nickel silver . This enabled the previously used arsenic-containing white copper to be replaced.
use
After Alfred Krupp filed a patent application for the spoon roller in 1838 , nickel silver was used for the industrial production of cutlery . Even today it is the basic material for silver-plated cutlery. It is used for precision mechanical and electrotechnical devices, medical devices, zippers , jewelry , snaffle bits , parts of wind instruments and glasses, and as a material for frets in stringed instruments . The rail profiles of model trains , precision mechanical springs and connectors of electrical engineering consist sometimes of nickel silver, because the oxide is electrically conductive. In slashing and stabbing weapons nickel silver is a common material for the guard in firearms for the grain of sight because the color of the metal provides a good contrast to black. In the case of coinage, nickel silver was initially used for trial coining around 1900. A well-known early coinage in nickel silver is the 1 billion mark piece of the province of Westphalia from 1923. Numerous commemorative coins of the GDR were made from nickel silver. Keys, especially those for high-quality lock cylinders and locking systems, are often made of nickel silver because they are so hard-wearing. Some manufacturers also make the cylinder core in nickel silver (termed "low-wear core").
In practice, nickel silver solder is often referred to as a hard solder that consists of approx. 50% copper, 10% nickel, 40% zinc and approx. 0.2% silicon , manganese and tin each. The melting range is 890-920 ° C.
literature
- 1935: Rudolf Krulla: German silver: properties, production, processing, manufacturing errors , use (= research on metal science and X-ray metallography. Volume 17). Hanser (on commission), Munich 1935, DNB 580472116 , OCLC 313222843 .
- 1953: Karl Waßmann: Study on German Silver . Göttingen 1953, DNB 480390460 , OCLC 73917073 (Dissertation University of Göttingen, Faculty of Mathematics and Natural Sciences, September 21, 1953).
- 1953: Forschungsgesellschaft Blechverarbeitung Düsseldorf (Ed.): Chemical shine of brass and nickel silver . Westdeutscher Verlag, Cologne / Opladen 1953, OCLC 73406128 .
- 1966: Dieter Bialas: X-ray structure determination with the help of the anomalous dispersion of orderly nickel silver alloys . Berlin 1966, DNB 481346430 (Dissertation, Free University of Berlin, Faculty of Mathematics and Natural Sciences, May 18, 1966).
- 1967: Kurt Dies: Copper and Copper Alloys in Technology , Springer, Berlin 1967, 2014, ISBN 978-3-642-48932-7 .
- 1980: Copper-nickel-zinc alloys . In: Deutsches Kupfer-Institut (Ed.): Alloys of copper with tin, nickel, lead and other metals . Berlin 1980, DNB 452747473 , OCLC 257691191 .
Web links
- German silver is an alloy of copper, nickel and zinc. In: jewelry knowledge. BeyArs GmbH, accessed on November 24, 2008 .
Individual evidence
- ↑ Alsenīd in Meyers Großes Konversations-Lexikon 1905. Full text: "Alsenīd, galvanically silvered nickel silver."
- ↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 4: M-Pk. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1985, ISBN 3-440-04514-5 , p. 2773.
- ^ Friedrich Wilhelm Barentin: Textbook of technology for secondary and commercial schools. 3rd edition, Georg Friedrich Heyer, 1848, p. 15.