3421. Tin and Zinc

3421.    Tin and Zinc. Tin and zinc, of each 1 part, is almost as tenacious as brass, and melts at 900° Fahrenheit.

3422. Pewter

3422.   Pewter. Tin, 100 parts; antimony, 8 parts; copper, 4 parts; and bismuth, 1 part, constitute the compound commonly called pewter.

3423. Alloys of Steel

3423.    Alloys of Steel. Steel is successfully alloyed with other metals, improving its qualities for some purposes, 1/500 part of silver adds immensely to the hardness of steel, and yet increases its tenacity, 1/100 part of platinum, though not forming so hard an alloy as the silver and steel, gives a very great degree of toughness. Rhodium, palladium, iridium, and osmium make steel very hard, but their use, from their cost, is confined mainly to the experimental laboratory. Platinum, in its malleable state, may be cut with a knife; but with steel it forms an alloy not to be touched with a file.

3424. Iron, Copper, and Zinc

3424.    Iron, Copper, and Zinc. An alloy consisting of 10 parts cast iron, 10 copper, and 80 zinc, does not adhere to the mould in casting, and it is of a beautiful lustre when filed and polished. The least fusible metals are melted first, and the zinc last, in making it.

3425. Ormolu, or Mosaic Gold

3425.    Ormolu, or Mosaic Gold. Copper and zinc, equal parts; melt together at the lowest possible temperature at which copper will fuse, and stir so as to produce a perfect admixture of the metals; then add gradually, small portions of zinc at a time, until the alloy acquires the proper color, which is perfectly white, while in the melted state. It must then be at once cast into figured moulds. This alloy should contain from 52 to 55 per cent, of zinc.

3426. White Metal

3426.    White Metal. Lead, 10 ounces; bismuth, 6 ounces; and antimony, 4 drachms; or, 2 pounds antimony, 8 ounces brass, and 10 ounces tin.

3427. French Alloy for Forks and Spoons

3427.    French Alloy for Forks and Spoons. This is a beautiful white metal, very hard, and taking a fine polish. It is composed of 69.8 parts of copper, 19.8 parts nickel, 5.5 of zinc, and 4.7 of cadmium.

3428. French Silver

3428.    French Silver. The new French silver is apparently an improvement on the old-fashioned German silver, and it is stated to be applicable to all the purposes to which ordinary commercial silver is applicable. It is composed of copper, 56 per cent., nickel, 40.64, tungsten, 2.0, aluminum, 0.56. It is a white, ductile, malleable, tenacious, sonorous alloy; its specific gravity is nine-tenths that of silver, its metallic lustre superior to that of silver, and its fusibility less, probably on account of the tungsten it contains.

3429. The Alloys of Aluminum

3429.    The Alloys of Aluminum. We have to distinguish between alloys in which the aluminum predominates and such ones in which the other metals outweigh the latter. Those impart to the aluminum new properties. Iron and copper do not act injuriously if the admixture is not considerable. In regard to toughness, the union of 7 per cent, of iron can scarcely bo distinguished from pure aluminum. Both metals easily combine with each other. Commercial aluminum mostly contains iron; it remains ductile with as much as 10 per cent, of copper, and when containing only half as much, it may be worked still easier. If alloyed with small quantities of zinc, tin, gold, or silver, the metal is rendered hard and more brilliant, but remains ductile. Especially recommended is the alloy consisting of 97 per cent, of aluminum, and 3 per cent of zinc. The alloy with 7 per cent, of tin can be worked well, but does not take a very fine polish, and cannot be cast, since a more fusible alloy with a large proportion of tin is separated. Aluminum and lead do not unite. The composition with 3 per cent, of silver and 97 of aluminum possesses a beautiful color, and in equal parts they yield an alloy of the hardness of bronze. The union of 99 per cent, of aluminum and 1 of gold is, though hard, still ductile; its color is that of green gold. With 10 per cent, of gold, the composition is rendered crystalline. In combining aluminum with copper, the latter must be melted first, and the former added gradually in small portions at a time. A combination of 10 parts aluminum and 90 parts copper produces a fine aluminum bronze, which, however, is brittle after the first mixing ; it increases in strength and tenacity only after successive fusions, but with the loss, each time, of a little aluminum. This bronze may be forged at a dull red heat without presenting flaws or cracks. Like copper, it is rendered more ductile by being heated and plunged into cold water.