NICKEL AND ITS ALLOYS Nickel.—Pure nickel is a metal of a silvery-wbite polish and strong lus ter. When highly polished it is dif ficult to tell nickel from polished sil ver. It has the valuable property of not tarnishing on exposure to the air. To break a nickel wire requires 11 times the pull that an iron wire of the same thickness does. Nickel is hard and melts with great difficulty. It may be dissolved slowly in dilute sul phuric or hydrochloric acid, and rap idly in nitric acid and aqua regia.
The principal uses of nickel are for nickel plating, for coinage, and for alloys.
German silver, or nickel silver, is brass with the addition of to of nickel. It is intended as an imitation of silver. This alloy has been in use in China from a remote antiquity. The white copper or pakfong of China contains 40.4 copper, 31.6 nickel, 95.4 zinc, 9.6 iron.
For German silver, use about 1 nickel, 1 zinc, 9 copper. A little lead may be added for casts.
Or, for a cheaper quality, 8 cop per, 9 nickel, 3.5 zinc. But if less than nickel is used the result will be little better than brass.
Imitation silver consists of 8 cop per, 3 nickel, 3.5 zinc. This is a beau
tiful alloy which takes a high polish much like silver.
Or 8 copper, 4 nickel, 3.5 zinc is an imitation of silver having a faint shade of blue. The addition of 9 or 3 per cent of iron renders it white, but less malleable.
A very malleable German silver is 10 copper, 6 zinc, 4 silver.
Chinese •tutenag is 8 copper, 3 nick el, 6.5 zinc. This is fusible, hard, and not easily rolled. Good German sil ver is of a silver-white color, ductile as brass, hard, and takes a high pol ish. On account of the cost of nickel, various cheaper white metals have taken the place of German silver, but the latter is still extensively used in the arts.
To make German silver, granulate the metals, mix them thoroughly, cov er with charcoal, and stir while melt ing.
Nickel steel contains 3i per cent nickel, as made at the Bethlehem works. It is used for armor plate, but is still too costly for other pur poses. Probably nickel will be cheap er in future, as it has steadily de clined in price with improved methods of manufacture.