Word Finder - alloy

definition

A metal that is a combination of two or more elements, at least one of which is a metal.

definition

A metal of lesser value, mixed with a metal of greater value.

example

gold without alloy

definition

An admixture; something added which stains, taints etc.

definition

Fusion, marriage, combination.

The alloy with 12% of silicon is white, hard and brittle.

Sometimes the whole alloy is a uniform solid solution.

The alloy of silver and copper is called sterling silver.

Tantalum pentafluoride, TaF5, for a long time only known in solution, may be obtained by passing fluorine over an alloy of tantalum and aluminium, and purifying by distillation in a vacuum.

The term "alloy" does not necessarily imply obedience to the laws of definite and multiple proportion or even uniformity throughout the material; but some alloys are homogeneous and some are chemical compounds.

It would seem, indeed, that any process by which the particles of two metals are intimately mingled and brought into close contact, so that diffusion of one metal into the other can take place, is likely to result in the formation of an alloy.

Gold and Silver.-Electrum is a natural alloy of gold and silver.

The metals used in different combinations included tin, aluminium, arsenic, antimony, bismuth and boron; each of these, when united in certain proportions with manganese, together with a larger quantity of copper (which appears to serve merely as a menstruum), constituted a magnetizable alloy.

Sometimes in the same design we see gold of three different hues, obtained by varying the alloy.

We must not take it for granted, when the freezing-point curve gives no indication of the compound, that the compound does not exist in the solid alloy.

If now we wish to represent the variations in some property, such as fusibility, we determine the freezing-points of a number of alloys distributed fairly uniformly over the area of the triangle, and, at each point corresponding to an alloy, we erect an ordinate at right angles to the plane of the paper and proportional in length to the freezing temperature of that alloy.

Gold and Zinc.-When present in small quantities zinc renders gold TABLE II.-Gold brittle, but it may be added to gold in larger quantities without destroying the ductility of the precious metal; Peligot proved that a triple alloy of gold, copper and zinc, which contains 5.8% of the lastnamed, is perfectly ductile.

The alloy of the point e is the ternary eutectic; it deposits the three metals simultaneously during the whole period of its solidfication and solidifies at a constant temperature.

When a pure metal is cooled to a very low temperature its electrical conductivity is greatly increased, but this is not the case with an alloy.

When a current is passed through a solid alloy, a series of Peltier effects, proportional to the current, are set up between the particles of the different metals, and these create an opposing electromotive force which is indistinguishable experimentally from a resistance.

If the alloy were a true chemical compound the counteracting electromotive force should not occur; experiments in this direction are much needed.

Manganese not only forms with iron several alloys of great interest, but alloyed with copper it is used for electrical purposes, as an alloy can thus be obtained with an electrical resistance that does not alter with change of temperature; this alloy, called manganin, is used in the construction of resistance-boxes.

Aluminium, when alloyed with a few per cent of magnesium, gains greatly in rigidity while remaining very light; this alloy, under the name of magnalium, is coming into use for small articles in which lightness and rigidity have to be combined.

One of the most interesting amongst recent alloys is Conrad Heusler's alloy of copper, aluminium and manganese, which possesses magnetic properties far in excess of those of the constituent metals.

The presence in an alloy of a eutectic which solidifies at a much lower temperature than the main mass, implies a great reduction in tenacity, especially if it is to be used above the ordinary temperature as in the case of pipes conveying super-heated steam.

The alloy with mercury-gold amalgam-is so readily formed that mercury is one of the most powerful agents for extracting the precious metal.

Other metals which find application in the metallurgy of gold by virtue of their property of extracting the gold as an alloy are lead, which combines very readily when molten, and which can afterwards be separated by cupellation, and copper, which is separated from the gold by solution in acids or by electrolysis; molten lead also extracts gold from the copper-gold alloys.

A greenish alloy used by goldsmiths contains 70% of silver and 30% of gold.

The Japanese use for ornament an alloy of gold and silver, the standard of which varies from 350 to 500, the colour of the precious metal being developed by " pickling " in a mixture of plum-juice, vinegar and copper sulphate.

The common alloy, Shi-ya-ku-Do, contains 70% of copper and 30% of gold; when exposed to air it becomes coated with a fine black patina, and is much used in Japan for sword ornaments.

Molten alloys containing more than 80% of silver deposit on cooling the alloy AuAgs, little gold remaining in the mother liquor.

The alloy of II parts gold and i part of zinc is, however, stated to be brittle.

The alloys of tin and gold are hard and brittle, and the combination of the metals is attended with contraction; thus the alloy SnAu has a density 14.243, instead of 14.828 indicated by calculation.

Matthiessen and Bose obtained large crystals of the alloy Au 2 Sn 5, having the colour of tin, which changed to a bronze tint by oxidation.

In these proportions the density of the alloy is less than the mean of its constituent metals.

These metals are stated to alloy in all proportions.

The alloy of 4 parts of gold and i part of palladium is white, hard and ductile.

Eleven parts of gold and i of nickel yield an alloy resembling brass.

In the " dry " methods the silver is converted into sulphide or chloride, the gold remaining unaltered; in the " wet " methods the silver is dissolved by nitric acid or boiling sulphuric acid; and in the electrolytic processes advantage is taken of the fact that under certain current densities and other circumstances silver passes from an anode composed of a gold-silver alloy to the cathode more readily than gold.

The fusion results in the formation of a gold-antimony alloy, from which the antimony is removed by an oxidizing fusion with nitre.

The sulphur and litharge, or Pfannenschmied, process was used to concentrate the gold in an alloy in order to make it amenable to " quartation," or parting with nitric acid.

The first process consists essentially in heating the alloy with salt and brickdust; the latter absorbs the chloride formed, while the gold is recovered by washing.

The second process depends upon the fact that, if chlorine be led into the molten alloy, the base metals and the silver are converted into chlorides.

It is now rarely practised, although in some refineries both the nitric acid and the sulphuric acid processes are combined, the alloy being first treated with nitric acid.

It used to be called " quartation " or " inquartation," from the fact that the alloy best suited for the operation of refining contained 3 parts of.silver to I of gold.

It is applicable to any alloy, and is the best method for parting gold with the exception of the electrolytic method.

The alloy, after the preliminary refining, is granulated by being poured, while molten, in a thin stream into cold water which is kept well agitated.

They are provided with lids, made either of lead or of wood lined with lead, which have openings to serve for the introduction of the alloy and acid, and a vent tube to lead off the vapours evolved during the operation.

Or the alloy is dissolved in aqua regia, the solution filtered from the insoluble silver chloride, and the gold precipitated by ferrous chloride.

In the wet process the ores, in which the bismuth is present as oxide or carbonate, are dissolved out with hydrochloric acid, or, if the bismuth is to be extracted from a matte or alloy, the solvent employed is aqua regia or strong sulphuric acid.

A brittle potassium alloy of silver-white colour and lamellar fracture is obtained by calcining 20 parts of bismuth with 16 of cream of tartar at a strong red heat.

This may be accomplished by using a vessel with a somewhat wide bottom, and inserting the substance so that it may be volatilized very rapidly, as, for example, in tubes of Wood's alloy, D and by filling the tube with hydrogen.

The tsien is a round disk of copper alloy, with a square hole punched through the centre for stringing.

In the Gira river the valuable alloy osmiridium has been discovered.

Its general plan is that of a Greek cross, with two great naves and three aisles, twenty side-chapels and a magnificent high altar supported by marble columns and surrounded by a tumbago balustrade with sixty-two tumbago statues carrying elaborate candelabra made from a rich alloy of gold, silver and copper.