Cu Al Zn Fe
1. Fe + Zn + (Al + Cu_{12}) = 0.8386 + 0.0305 + 0.0712 + 0.0600
2. Fe + Zn + (Al + Cu_{15}) = 0.8666 + 0.0249 + 0.0588 + 0.0496
The tensile strength of the above alloys as drawn wire is 82,000 pounds
for the first, and 107,000 pounds for the second.
All of the alloys in which zinc or zinc and iron enter in place of
silver, the color is affected and the luster diminished.
With nickel and platinum for the third element, we have:
Cu Al Ni
Ni + 6 (Al + Cu_{6}) = 0.9129 + 0.0634 + 0.0237
Pl + 21 (Al + Cu_{6}) = 0.9117 + 0.0656 + 0.0225
Those alloys into which platinum is introduced are less affected by
acids than those in which silver takes the place of platinum; platinum
producing a higher luster than silver.
In the alloys of aluminum bronze with the more difficultly fusible
metals, it is preferable to fuse the bronze first, then add the other
metal in small shavings or wire; by this means the less fusible metal
absorbs the other without raising the heat of the furnace excessively.
Add the least fusible metal last, a little at a time, allowing the heat
of the melted metal to fall by degrees, which prevents boiling and
evaporation. The crucibles for mixing the alloys should be of plumbago
lined with a paste of lime.
Avoid sand crucibles, as silicium may be reduced and absorbed by the
aluminum, inducing brittleness. If found brittle, remelt with cryolite
as a flux, or stir the melted metal or alloy with a hard wood stick
that has been slightly charred.
In adding aluminum to the copper, cut it in small pieces and push it to
the bottom of the crucible with a dry, hard wood stick split so as to
hold the pieces.
Sodium chloride (common salt) calcined to evaporate the water, and
caustic soda with pulverized charcoal, may be used as a flux for pure
aluminum. Avoid borax as a flux, as its metal may suffer reduction,
making the aluminum brittle. Aluminum will alloy with tin alone, but is
liable to separate on refusion. Does not alloy with lead.
Bismuth, even in minute quantity, makes these alloys brittle.
The East Indian steel called _wootz_ is, according to analysis, alloyed
with aluminum. No reliable solder has yet been found for pure aluminum
that will flow freely under the blow pipe or from a soldering iron.
A process recently adopted in France is to plate the parts to be united
with alloys of tin 5, aluminum 1, upon which tin solder will flow.
These proportions may be slightly varied to suit requirements for
hardness.
Harder solders to be used with a blowpipe may be made with alloys of
zinc, tin, and aluminum.
Aluminum is now made at the works of M. Deville, at Javelle, near
Paris, and at Salindres, France; also at Birmingham, England. The
product of late has reached the value of $20,000 annually in Europe.
It has been claimed to be made in Philadelphia at a reduced cost. The
present price in New York is $1.25 per oz. As its bulk is over four
times as great as silver, its comparative cost is but one-third that of
silver--a point not often considered when the price is quoted.
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