Alloy

“ An alloy, a compound mixed with a pure metal to give it some desirable quality like strength.
[3] In metallurgy, impurities (like alloy compounds) that rise to the surface when metals are heated; the impurities can be poured off leaving pure metal. ”

“ It is well known that alloy makes all metals brittle, and that when there is a penetration, that is, an augmentation in the specific gravity, the alloy is so much the more tempered as the penetration is the greater, and the mixture becomes the more intimate, as is perceived in the alloy called bell-metal, although it be composed of two very ductile metals. ”

“ Much information as to the nature of an alloy can be obtained by placing several small ingots of the same alloy in a furnace which is above the melting-point of the alloy, and allowing the temperature to fall slowly and uniformly. We then extract one ingot after another at successively lower temperatures and chill each ingot by dropping it into water or by some other method of very rapid cooling. ”

“ If a combination of metals was dissolved, the restorative fluid gave back no alloy, but the separate metals. If an organic substance—that is, vegetable or animal matter—was put in the solution, it could be restored, but unorganized—a chaotic mass of tissues.
"My grandfather made the next step forward, and his restoring chemical not only gave back iron for iron, but brass—which is an alloy—for brass, bronze for bronze, spelter for spelter, and so on. ”

“ Tin.—A filed rod of tin-aluminum alloy plunged in cold water gives off for some minutes bubbles of gas, composed of hydrogen and oxygen in explosive proportions. An unfiled rod, or a filed rod of either aluminum or tin, is without action, though the unfiled rod of alloy will act on boiling water. The filed rod of alloy, in faintly acid solution of copper or zinc sulphate, becomes covered with a deposit of copper or zinc, while bubbles of oxygen are given off. ”

“ Regarded as descriptive of the genesis of an alloy from a uniform liquid containing two or more metals, the term is not incorrect, and it may have acted as a signpost towards profitable methods of research. But modern work has shown that, although alloys sometimes contain solid solutions, the solid alloy as a whole is often far more like a conglomerate rock than a uniform solution. ”

“ Some of these are occasionally employed for special purposes in the arts in their pure state; but where hardness is to be a distinguishing characteristic, combined with certain variations in shades of colour, a union is effected of two or more of these metals in different proportions, by fusion and stirring, so as to form the requisite alloy. Metals used in the pure state, that is, without any mixture of alloy, have very few applications in regard to industrial pursuits and the arts. ”

“ One metal does not alloy indifferently with every other metal, but it is governed in this respect by peculiar affinities; thus, silver will hardly unite with iron, but it combines readily with gold, copper, and lead. In comparing the alloys with their constituent metals, the following differences may be noted; in general, the ductility of the alloy is less than that of the separate metals, and sometimes in a very remarkable degree; on the contrary, the alloy is usually harder than the mean hardness of its constituents. ”

“ The types cast by the type-founder are oblong square pieces of metal, each having, on one end of it, a letter or character, in relief. The metal of which these important instruments are composed, is commonly an alloy consisting principally of lead and antimony, in the proportion of about five parts of the former to one of the latter. ”

“ I fused the gold on a lump of charcoal with an alcohol blowpipe. Please tell me how to work it. A. You fail to state the proportions of your alloy. There may be an excess of zinc and copper, or the fusion may not have been complete. Place it, together with several small pieces of rosin and a little borax or carbonate of soda, in a small blacklead crucible, and heat to very bright redness over a good fire. If this does not obviate the difficulty, fuse the alloy with about three times its weight of nitrate of potassa (saltpeter) , and treat the mass when cold with dilute sulphuric acid. ”

“ Ee is a eutectic line, as also are E′e and E′′e. The alloy of the point e is the ternary eutectic; it deposits the three metals simultaneously during the whole period of its solidification and solidifies at a constant temperature. As the lines of the surface which correspond to Ee, &c., slope downwards to their common intersection it follows that the alloy e has the lowest freezing-point of any mixture of the three metals; this freezing-point is 96° C., and the alloy e contains about 32% of lead, 15·5% of tin and 52·5% of bismuth. ”

“ After melting completely an alloy of lead and silver, if we allow it to cool very slowly, continually stirring it meanwhile with a rake, we shall observe at a certain period a continually increasing number of imperfect little crystals, which may be taken out with a drainer, exactly as we may remove the crystals of sea salt deposited during the concentration of brine, or those of sulphate of soda, as its agitated solution cools. ”

“ Lipowitz’s Alloy.—I.—This alloy is composed of cadmium, 3 parts; tin, 4; bismuth, 15; and lead, 8. The simplest method of preparation is to heat the metals, in small pieces, in a crucible, stirring constantly, as soon as fusion {62} begins, with a stick of hard wood. The stirring is important, in order to prevent the metals, whose specific gravity varies considerably, from being deposited in layers. The alloy softens at 140° F. and melts completely at 158° F. The color is silvery white, with a luster like polished silver, and the metal can be bent, hammered, and turned. ”

“ Lead.—When aluminum is melted and lead is added in proportion greater than 10 per cent, the metals separate on cooling into three layers—lead, aluminum, and between them an alloy containing from 90 to 97 per cent of aluminum. ”

“ These data being assumed as the bases of the parting operation, 60 pounds of gold and silver alloy or garble finely granulated, containing not less than 40 pounds of silver, are to be introduced into the ten-gallon alembic of platinum, fig. 931., and 80 pounds of nitric acid, of 1·320, is to be poured over the alloy; a quantity which will measure 6 gallons imperial. As for the bulk of the alloy, it is considerably less than half a gallon. Abundance [1059] of space therefore remains in the alembic for effervescence and ebullition, provided the fire be rightly tempered. ”

“ In forming the alloy, the refractory compound, copper, is first melted separately, the other metals, tin, zinc, etc., previously heated, being then added; the whole is then stirred and the casting carried out without loss of time. The process of forming the alloy must be effected quickly, so that there may be no loss of zinc, tin, or lead through oxidation, and also no interruption to the flow of metal, as metal added after an interval of time will not combine perfectly with the metal already poured in. ”

“ It may conveniently be extended to similar mixtures of sulphur and selenium or tellurium, of bismuth and sulphur, of copper and cuprous oxide, and of iron and carbon, in fact to all cases in which substances can be made to mix in varying proportions without very marked indication of chemical action. 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. In what follows we shall confine our attention principally to metallic alloys. ”

“ Though there may be discussions concerning the extent of the transformations to which it is subjected, though some believe they affect the chemical condition of the alloy, while others limit its power to physical effects, it is nevertheless true—and this brings us back to our subject—that the mass of these metals is at work, and that it only slowly attains the phase of complete repose. ”

“ The alloy is usually formed by fusing metals together; when molten they dissolve in each other and form an intimate union, often (as in industrial uses) producing a new metal with qualities quite different from those of the separate elements of the mixture. ”

“ That metallic alloys tend to be formed in definite proportions of their constituents is clear from the circumstance that the native gold of the auriferous sands is an alloy with silver, in the ratios of 1 atom of silver united to 4, 5, 6, 12 atoms of gold, but never with a fractional part of an atom. ”

“ An alloy, containing from one-twelfth to one-tenth of copper, constitutes the silver coin of most nations; being a harder and more durable metal under friction than pure silver. When this alloy is boiled with a solution of cream of tartar and sea-salt, or scrubbed with water of ammonia, the superficial particles of copper are removed, and a surface of fine silver is left. ”

“ They often form liquid solutions, similar to alloys in metals.
7. Non-metals are electronegative, and with H, or with H and O, form acids.
Examine brass, bronze, bell-metal, pewter, German silver, solder, type-metal.
223. Alloys.-An alloy is not usually a definite chemical compound, but rather a mixture of two or more metals which are melted together. ”

“ But I may tell you that I have found an alloy that is unequalled in the known world for strength, durability and lightness. It weighs a little more than pure aluminum, but has a thousand times its tensile strength. ”

“ II.—Make an alloy of 3 ounces of lead, 2 ounces of tin, and 5 ounces of bismuth. Put a portion of this alloy into the globe and expose it to a gentle heat until the compound is melted; it melts at 197° F.; then by turning the globe slowly round, an equal coating may be laid on, which, when cold, hardens and firmly adheres.
Resilvering Mirrors—If mirrors coated with amalgam become damaged they may sometimes be successfully repaired by one of the following processes:
I.—Place the old mirror in a weak solution of nitric acid—say 5 per cent—which immediately removes the silver. ”

“ When the copper is in excess the tint of the alloy is slightly red, and the structure, as shown at a fractured surface, is coarsely crystalline. As the proper proportions are more nearly attained, the crystalline structure becomes finer, the colour whiter, and the crystals brighter. The alloy is ready for use when the maximum brightness is attained and the grain is fine. ”

“ On melting together tin and lead, and allowing the alloy to cool, we find our expectation justified; for by pouring off the fluid portion which remains after solidification has commenced, and repeating this several times with the portion so removed, we at length obtain an alloy which solidifies at the constant temperature of 180°, when the melting-point of tin is taken as 228°. ”

“ Tin and zinc. This alloy is easily made by fusion. The metals seem to unite in any proportion. I melted together 29 parts zinc and 52 tin (1 atom of each) , and obtained a white hard alloy of about 6.8 specific gravity. When 2 atoms tin and 1 zinc are united the specific gravity is 6.77, which is below the mean. The alloy appears to be very hard and tenacious ”

“ When we wish to alloy three or more metals, we often experience difficulties, either because one of the metals is more oxidable, or denser, or more fusible, than the others, or because there is no direct affinity between two of the metals. ”

“ One of the alloys most useful to the arts is brass; it is more ductile and less easily oxidised than even its copper constituent, notwithstanding the opposite nature of the zinc. This alloy may exist in many different proportions, under which it has different names, as tombac, similor, pinchbeck, &c. Copper and tin form, also, a compound of remarkable utility, known under the names of hard brass, for the bushes, steps, and bearings of the axles, arbours, and spindles in machinery; and of bronze, bell-metal, &c. ”

“ Alloys.—Gold forms alloys with most metals, and of these many are of great importance in the arts. The alloy with mercury—gold amalgam—is so readily formed that mercury is one of the most powerful agents for extracting the precious metal. With 10% of gold present the amalgam is fluid, and with 12.5% pasty, while with 13% it consists of yellowish-white crystals. ”

“ TO COMBINE LEAD WITH OTHER METAL. If you wish for economy in combining lead with the metal in order to lessen the amount of tin which is necessary in the metal, first alloy the lead with the tin and then add the molten copper. ”

“ It is certain that the structure existing in the alloy is closely connected with the mechanical properties, such as hardness, toughness, rigidity, and so on, that make particular alloys valuable in the arts, and many efforts have been made to trace this connexion. ”

“ Its rich deep tones of black, and the splendid polish which it is capable of receiving, render it alike a perfect ground for inlaid designs of gold, silver, and copper, and for being similarly inlaid in them. This alloy, too, possesses physical properties which are of extreme importance to the worker in metals, and enable him to manipulate and fashion it as he desires. ”

“ This uniform distribution of a solid substance throughout the mass of another, so as to form a homogeneous material, is called ``solid solution,'' and we may say that solid silver can dissolve copper. Solid solutions are probably very common in alloys, so that when an alloy of two metals shows two constituents under the microscope it is never safe to infer, without further evidence, that these are the two pure metals. Sometimes the whole alloy is a uniform solid solution. ”