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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    hammering, &c., and require occasional annealing or softening by heat to bring them back again to their normal condition. The relative malleability of metals is determined by the degrees of thinness of the sheets that can be produced by hammering or by rolling irithout annealing. The more impo]-tant metals are arranged according to their malleability in the follow- ing table: Oedeb op Malleability. Most. Mdllmblc. 1. Gold. JO. Zinc. 2. Silver. ii_ ii-OQ 3. Aluminium. 12. Nickel. 4. Copper. 13 Mercury (frozen). 5- Least Malleable. 6. Platinum. 14. Bismuth ^ 7. Palladium. 15. Antimony hirittle. ^- Lead. 16. Iridium J 9. Cadmium. Brittleness.—When the metals are void of mal- leability, and have a tendency to fly to pieces when hammered or rolled, they are said to be brittle. Antimony and bismuth are characteristic brittle metals at all temperatures. Some metals which are very malleable at one tem- perature are brittle at another. Zinc, for example, is brittle at ordinary temperatures, but when heated to between 100° and 150° C. (2 r 2^-302° F.) it becomes malleable and can readily be rolled into thin sheets, whilst at 200° C. (392° F.) and upwards it again becomes brittle and can easily be powdered in a mor- tar. Other metals which are malleable at ordinary temperatures become brittle when heated to a tempera- ture just below their melting-points ; lead, tin, copper, and aluminium are examples.