Читать книгу Henley's Formulas, Recipes and Processes (Applied Chemistry) - Various - Страница 236
German Silver Or Argentan.
ОглавлениеThe composition of this alloy varies considerably, but from the adjoined figures an average may be found, which will represent, approximately, the normal composition:
| Copper | 50 to 66 parts |
| Zinc | 19 to 31 parts |
| Nickel | 13 to 18 parts |
The properties of the different kinds, such as their color, ductility, fusibility, {70} etc., vary with the proportions of the single metals. For making spoons, forks, cups, candlesticks, etc., the most suitable proportions are 50 parts of copper, 25 of zinc, and 25 of nickel. This metal has a beautiful blue-white color, and does not tarnish easily.
German silver is sometimes so brittle that a spoon, if allowed to fall upon the floor, will break; this, of course, indicates faulty composition. But the following table will show how the character of the alloy changes with the varying percentage of the metals composing it:
| Copper | Zinc | Nickel | Quality | |
|---|---|---|---|---|
| I. | 8 | 3.5 | 4 | Finest quality. |
| II. | 8 | 3.5 | 6 | Beautiful, but refractory. |
| III. | 8 | 6.5 | 3 | Ordinary, readily fusible. |
| IV. | 52 | 26.0 | 22 | First quality. |
| V. | 59 | 30.0 | 11 | Second quality. |
| VI. | 63 | 31.0 | 6 | Third quality. |
The following analyses give further particulars in regard to different kinds of German silver:
