An alloy is a substance produced by melting together two or more metals, sometimes a definite chemical compound, but more generally a solid solution of some such compound in an excess of one of the components. Most metals mix together in all proportions, but others unite only in definite proportions, and form true chemical compounds. Others, again, will not alloy, and when fused together, and then allowed to solidify, form not a homogeneous mixture, but a conglomerate of distinct masses.
Alloys differ from their components in most of their physical properties. Their hardness is in general increased, their malleability and ductility impaired. The colour of an alloy may closely resemble that of one of the components, or may be entirely different from the colours of both. Its specific gravity is sometimes less than the mean of its component metals. Alloys are always more fusible than their components, at any rate than the least fusible component. Newton's fusible metal, composed of three parts of tin, two or five parts of lead, and five or eight parts of bismuth, melts at temperatures varying from 198 degrees to 210 degrees Fahrenheit (and therefore in boiling water); its components fuse respectively at the temperatures 442 degrees, 600 degrees and 478 degrees Fahrenheit. Sometimes each metal retains its own fusing-point. With few exceptions metals are not much used in a pure state. 19th century British gold coins contained eight per centsilver; 19th century British silver coins 7.1 per centcopper. Printer's types were made from an alloy of lead and antimony; brass and a numerous list of other alloys are formed from copper and zinc; bronze from copper and tin. Research Alloy
Abbreviations
SciTech
Research Alloy