Henley's Twentieth Century Formulas, Recipes and Processes. VariousЧитать онлайн книгу.
In some kinds of German silver are found varying quantities of iron, manganese, tin, and very frequently lead, added for the purpose of changing the properties of the alloy or cheapening the cost of production. But all these metals have a detrimental rather than a beneficial effect upon the general character of the alloy, and especially lessen its power of resistance to the action of dilute acids, one of its most valuable properties. Lead makes it more fusible; tin acts somewhat as in bronze, making it denser and more resonant, and enabling it to take a higher polish. With iron or manganese the alloy is whiter, but it becomes at the same time more refractory and its tendency toward brittleness is increased.
Substitutes For German Silver.
There are many formulas for alloys which claim to be substitutes for German silver; but no one of them has yet become an article of general commerce. It will be sufficient to note these materials briefly, giving the composition of the most important.
Nickel Bronze.
—This is prepared by fusing together very highly purified nickel (99.5 per cent) with copper, tin, and zinc. A bronze is produced containing 20 per cent of nickel, light-colored and very hard.
Bismuth Bronze.—
| I | II | III | IV | |
|---|---|---|---|---|
| Copper | 25.0 | 45.0 | 69.0 | 47.0 |
| Nickel | 24.0 | 32.5 | 10.0 | 30.9 |
| Antimony | 50.0 | — | — | — |
| Bismuth | 1.0 | 1.0 | 1.0 | 0.1 |
| Tin | — | 16.0 | 15.0 | 1.0 |
| Zinc | — | 21.5 | 20.0 | 21.0 |
| Aluminum | — | — | 1.0 | — |
I is hard and very lustrous, suitable for lamp reflectors and axle bearings; II is hard, resonant, and not affected by sea water, for parts of ships, pipes, telegraph wires, and piano strings; III and IV are for cups, spoons, etc.
Manganese Argentan.—
| Copper | 52 to 50 parts |
| Nickel | 17 to 15 parts |
| Zinc | 5 to 10 parts |
| Manganese | 1 to 5 parts |
| Copper, with 15 per cent phosphorus. | 3 to 5 parts |
Readily cast for objects of art.
Aphtite.—