A manual on dental metallurgy / by Ernest A. Smith.

  • Smith, Ernest A. (Ernest Alfred)
Date:
1903
Catalogue details

Licence: In copyright

Credit: A manual on dental metallurgy / by Ernest A. Smith. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    oxide. Water and dilute sulphuric acid are without action on the metal, but when heated with concen- trated sulphuric acid it is converted into antimony sulpbate. It is easily dissolved by hot hydrochloric acid as well as by cold aqua regia. It is rapidly oxidised without solution upon treatment with nitric acid, the white oxide formed collecting at the bottom of the vessel. Alkaline solutions have no action on the metal. It melts at a temperature a little above that required to melt zinc, its melting-point being 632'' C. (l 170° F.), and volatilises in the air at a bright red heat. It is the next lightest metal to aluminium, its density being 6.8. Uses for Dental Purposes.—The chief use of antimony in the dental laboratory is as a constituent of aboys for dies and counter-dies. Alloys.—The effect of antimony is to harden the metals with which it is alloyed and generally to impair the malleability and ductility of the malleable metals, in some cases rendering them brittle. Antimony and Lead.—The union of these metals is readily effected by melting. With excess of antimony the - alloys are hard, brittle, and very crystalline. With less than 15 per cent, of antimony lead alloys have the important property of expanding on cooling. (See ]). 210.J Antimony and Tin.—These metals unite to form alloys which are hard and less malleable than tin, and become brittle as the proportion of antimony increases. These metals when united form the basis (,f what is termed Britannia metal, many vaiieties of which coiisist of tin hardened with antimony. This