Wood's metal

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A piece of Wood's alloy

The Wood's Metal , Wood's metal or Wood's alloy (engl. Wood's metal ) is a bismuth alloy in the vicinity of the quaternary eutectic in the system bismuth - Lead - Cadmium - Tin , which melts at about 60 ° C. This means that hot water is enough to melt it.

composition

Wood's metal is made of

Without cadmium in the composition, but with 25% Sn, the alloy is called Roses Metall and melts at 94 ° C.

properties

safety instructions
Surname
  • Wood's metal
  • Wood's alloy
CAS number
  • 76093-98-6
  • 8049-22-7 (obsolete)
GHS labeling of hazardous substances
06 - Toxic or very toxic 08 - Dangerous to health 09 - Dangerous for the environment

danger

H and P phrases H: 330-341-350-361fd-372-410
P: 201-260-273-304 + 340 + 310-308 + 313-403 + 233
Toxicological data

> 10,000 mg kg −1 ( LD 50 ,  rat ,  oral )

Wood's metal is an odorless, silver-gray solid that is almost insoluble in water, which expands when it solidifies (bismuth has this property), so it has a density anomaly like water . The density is about 9.6 g / cm³.

use

Wood's metal is used as a fuse for sprinkler systems or electrical fuses because of its low melting point . In laboratories it is also used for heating baths (so-called metal baths). It was also often used as a joke article. A Wood's metal spoon was handed to a person when he or she drank a hot drink. When stirred, this spoon melted in the drink. This prank can no longer be carried out today because of the lead and cadmium content.

Historical

On March 20, 1860, the American dentist Barnabas Wood received a patent for a low-melting alloy that he used for dental fillings. Also for joining tin and tin alloys, i.e. H. as a low melting solder , he suggested it. It was also suggested for casts . In 1860 the behavior of the alloy was also examined by A. Lipowitz. Soon afterwards the alloy, which in its original composition melted at around 65 to 71 ° C, was named Wood's metal after its inventor, Barnabas Wood . A. Lipowitz called it "Wood's easy-flowing metal" and also named the actual inventor in the text. Nevertheless, Wood's metal is also called Lipowitz's metal or alloy, although sometimes a slightly different composition is specified, e.g. B. 27% Pb, 13% Sn, 10% Cd, balance Bi.

See also

Individual evidence

  1. ↑ Entry on Woodsche's metal. In: Römpp Online . Georg Thieme Verlag, accessed on June 19, 2014.
  2. ^ A b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 827.
  3. ↑ a b Woods metal data sheet at Sigma-Aldrich , accessed on July 29, 2017 ( PDF ).
  4. ↑ a b c Woodsches Metall data sheet (PDF) from Merck , accessed on January 19, 2011.
  5. ↑ Woodsches Metall ( Memento of December 3, 2008 in the Internet Archive ) in Meyers Lexikon Online.
  6. ^ Walter Wittenberger: Chemical laboratory technology . 7th edition, Springer, Vienna / New York 1973, ISBN 3-211-81116-8 , p. 155.
  7. ^ Finding Aid for the Barnabas Wood Papers MS.3459. Biographical / Historical Note. In: Special Collections Online. The University of Tennessee, Knoxville, accessed March 30, 2015 .
  8. ↑ Specification of a patent granted to Barnabas Wood, of Davidson County, State of Tennessee, for an improved alloy or metallic composition suitable for a metallic cement in the manufacture of Tin, Pewter, and other metals; Also useful for casting and other purposes . In: Journal of the Franklin Institute . tape 70 , no. 2 , August 1860, p. 125-128 , doi : 10.1016 / 0016-0032 (60) 90458-0 .
  9. ↑ Wood's fluid metal. In: Polytechnisches Journal . 158, 1860, pp. 271-272.
  10. ↑ A. Lipowitz: About Wood's easy-flowing metal. In: Polytechnisches Journal . 158, 1860, pp. 376-377.
  11. ^ Stephan Hasse: Foundry Lexicon . 19th edition. Fachverlag Schiele & Schoen, Berlin 2007, ISBN 978-3-7949-0753-3 , Lipowitzsches Metall, p. 779 , col. right .