Popular Science Monthly/Volume 42/December 1892/Nickel and its Uses
|NICKEL AND ITS USES.|
By J. T. DONALD, M. A.
CONSIDERABLE interest attaches to the metal nickel at the present time, principally for two reason: In the first place, experiments recently made in France, England, and America have shown that steel alloyed with a small percentage of nickel forms an alloy possessed of great strength and remarkable resisting powers. In the second place, the past few years have witnessed the discovery and initial development on a large scale of what are said to be practically inexhaustible deposits of nickel ore in what is known as the Sudbury District, of Canada.
Nickel may be said to be a modern metal, for its history goes back no further than a century and a half, although the word is much older. The origin of the name is curious and interesting. The men working in the German copper mines often came upon an ore which, though looking like copper ore, did not yield copper when smelted. Such ore they called kupfer-nickel—i. e., goblin copper—because they thought the nickels or spirits of the mine were deluding them with bad ore.
In 1751 the Swedish mineralogist Cronstedt discovered a new metal, which, some three years later, he succeeded in isolating in an impure state. Finding that his new metal was most abundant in kupfer-nickel, he allowed it to retain the name suggested by the old superstition of the German miners.
It was many years after this, however, before the metal was obtained in a state of purity and its properties satisfactorily determined, and it was much later still when nickel, in a state of comparative purity, became an article of commerce; indeed, until recently it was hardly known in the pure state outside of the laboratory. In 1804 Richter experimented with this metal and obtained it fairly pure by reducing the oxide with carbon in an earthen crucible. Almost seventy years later, Wharton, of the Camden Nickel Works, Camden, N. J., who has devoted so much attention to the metallurgy of nickel, exhibited at the Vienna Exposition vessels of pure forged nickel, which he made by strongly compressing the spongy mass obtained by reduction of the oxide. These exhibits at Vienna, and similar ones at Philadelphia in 1876, and at Paris in 1878, received but scant attention from scientific visitors. Chemists and metallurgists, as a rule, supposed they were nickel alloy, and were somewhat incredulous when informed that the objects were pure nickel; in fact, the commercial production of pure nickel by Wharton, as evidenced by these exhibits, was a genuine surprise to the metallurgical world.
A further advance in the metallurgy of nickel was made by Fleitmann, of Iserlohn, Westphalia, in 1879. He found that the purest nickel he could obtain on a commercial scale had a brittleness which did not belong to the pure metal, and in the course of investigation he was led to believe that the brittleness was caused by occluded carbonic oxide. He decided to attempt the removal of this by adding magnesium in minute quantity to the molten nickel, and was successful beyond expectation, for the nickel thus treated quickly loses its brittleness.
As to the properties of nickel, it will suffice to say that it is a hard silver-white metal with a steel-gray tinge; it may be rolled into thin plate or drawn into wire; it is not readily oxidized; it is attracted by the magnet and readily assumes a polar condition.
Turning now to consider the uses of this metal, we find that Thénard in 1825, in his Traité de Chimie, stated that nickel was not employed for any practical purpose. This statement is true only in reference to the pure metal; for, just as brass was known and used long before zinc was isolated, so nickel alloys were known and used long before Cronstedt's discovery of the metal. The Chinese appear to have been among the earliest users of nickel alloys, for as early as 1776 it was pointed out that Chinese packfong—i. e., white copper—is an alloy of copper, zinc, and nickel. The beginning of the manufacture of these alloys in Europe is due to a somewhat curious circumstance. In the old slags from disused copper-smelting works at Suhl in Prussian Saxony, and once known as the armory of Germany, white granules of metal were found. These were extracted and sold as Suhlian nickel silver, and in 1823 Brande showed that these white granules consist principally of an alloy of copper and nickel, and thus originated the manufacture of the widely used nickel alloys known as nickel or German silver. This German silver, so extensively used as the basis of electroplate, is, as is well known, an alloy of copper, zinc, and nickel, the proportions varying according to the use to which the alloy is to be put. Copper is the principal ingredient, and the nickel varies according to the color desired, for it is this metal that has the property of whitening the copper. Sometimes a little iron (from two to two and a half per cent) is added to the ingredients named, with the result of producing an alloy that is whiter and harder than the ordinary composition.
Doubtless all Americans know that nickel is used in coinage, but probably few are aware of the extent to which it is so used. As early as 1837 one Dr. Feuchtwanger, of New York, called attention to the suitability of nickel for coinage, and is said to have actually issued a number of one-cent and three-cent coins made of a nickel alloy. But the first national issue of a nickel-alloy coinage was made by Switzerland in 1850, the issue consisting of twenty, ten, and five centime pieces, containing respectively fifteen, ten, and five per cent of silver, alloyed with ten parts of nickel and twelve and a half parts of zinc, copper making up the balance. In 1857 an alloy consisting of eighty-eight parts of copper and twelve of nickel was adopted by the United States for the one-cent pieces. In 1860 Belgium instituted a nickel coinage, the alloy used for the purpose consisting of seventy-five parts of copper and twenty-five of nickel. This particular alloy appears to have given much satisfaction, for we find it adopted by the United States in 1865, by Brazil in 1872, by Germany in 1873, and still later by Jamaica.
It is not only in the form of an alloy that nickel is used in coinage. Improvements in the metallurgy of the metal have rendered possible a coinage of pure nickel, and it is interesting to note that Switzerland, which was the first to adopt a nickel-alloy coinage, was also the first to issue coins of the pure metal, the Swiss twenty-centime pieces coined in 1884 being pure nickel. In 1886 the Royal Berlin Mint executed for the Egyptian Government a nickel coinage, and during the same year a Birmingham firm coined in nickel five hundred thousand half-decimos and one million centimos for the Republic of Ecuador, while in 1887 Bolivia issued a nickel coinage. It thus appears that nickel is gaining in favor for subsidiary coinage, and not without cause. It is superior to copper in color, and, being more valuable, smaller coins are obtained; both the pure metal and the alloy are hard and thus wear well, and they possess the additional advantage that they can be manipulated only by skillful workmen. In this connection it is worthy of note and illustrative of the old saying, "There is nothing new under the sun," that a coin of the Bactrian king Euthydemos, who reigned about 235 years before Christ, is in composition very similar to the alloy adopted by Belgium, the United States, and other countries.
Nickel-plating annually calls for a large amount of the metal. The process is said to have been invented by Böttcher about 1848, and was first applied to firearms in order to prevent them from rusting, but is now applied to every description of iron and steel work. The effect, as is well known, is very fine, as the nickel, coating is white, bright, and hard, and, since it shows but very little tendency to oxidation, it retains its brightness for a long time.
Important as are the uses of the metal already indicated, the world's annual consumption has been small; not over a thousand tons was consumed in 1888, nickel-plating calling for more than half of this amount.
It is, however, in connection with one of the new uses of nickel—viz., as a constituent of nickel steel—that special interest attaches to the metal at present.
It is well known that nickel is frequently associated with iron in meteorites, and the view that the well-known and valuable qualities of meteoric iron might be due to the presence of nickel has not wanted advocates in the past.
Again, as far back as 1853, nickeliferous iron ores from Marquette, Mich., were found to produce iron possessing unusual toughness, a very white color, and a diminished liability to oxidation.
For a long time Nature's hints were neglected or disregarded, but in 1888 patents were taken out in England and France by different individuals for the preparation of nickel steel.
Tests of this alloy have been made by competent authorities, and the effect of the addition of small percentages of nickel to steel is seen in greatly reduced tendency to oxidation and increased strength. As an example of the superiority of this nickel steel, the following results of one of the tests may be given: A steel containing 4·7 per cent of nickel "showed an ultimate strength of thirty per cent and elastic limit of sixty to seventy per cent higher than those of mild steel, with a nearly equal ductility, and the valuable quality added of less liability to corosion." The authority who obtained these remarkable results adds: "Think for a moment of this in connection with the erection of the Forth Bridge or of the Eiffel Tower. If the engineers of those stupendous structures had had at their disposal a metal of forty tons strength and twenty-eight tons elastic limit, instead of thirty tons strength and seventeen tons elastic limit in the one case and, say, twenty-two tons strength and fourteen to sixteen tons elastic limit in the other, how many difficulties would have been reduced in magnitude as the weight of materials was reduced! The Forth Bridge would have become even more light and airy, and the Tower more netlike and graceful, than they are at present." And Sir Frederick Abel, in his presidential address at the Leeds meeting of the British Association, remarked, "It has been shown by Riley that a particular variety of nickel steel presents to the engineer the means of nearly doubling boiler pressures without increasing weight or dimensions."
On the other hand, it must be admitted that there are those who maintain that the future of nickel steel has been painted in too rosy colors. For example, in Stahl und Eisen for October, 1889, Prof. A. Ledebeer criticises the claims made for nickel steel, and predicts that the alloys of nickel and steel "belong to that class of inventions which crop up at intervals, finally to be buried in oblivion because of their impracticability." The criticisms of this German writer were practically answered by a report in some of the trade journals immediately after the appearance of his criticism, to the effect that there existed among steel-makers a demand for several thousand tons of ferro-nickel for use in the preparation of nickel steel; and trials of armor plate made by a board of United States naval experts at Annapolis, Md., have shown that nickel steel is superior to ordinary steel for armor plate. As a result of these tests the House of Representatives at Washington made an appropriation of one million dollars for the purchase of nickel for use in the manufacture of armor for the new armored war-ships.
Coming now to consider the source of the nickel of commerce, we find it is derived principally from two classes of ores—viz., a nickeliferous pyrrhotite and a silicate of nickel. A very remarkable deposit of the latter occurs in New Caledonia, one of the New Hebrides and a penal colony of France, and since the period when productive work was begun on these deposits it may be said that the New Caledonia mines have entirely controlled the market. The ore known as garnierite is a hydrosilicate of nickel and magnesia, and is found in beds of serpentine mixed with oxide of iron, chrome iron ore, and a little cobalt. It is especially valuable on account of its entire freedom from arsenides and sulphides. Similar ores occur on this continent—for instance, in North Carolina and Oregon—but these deposits have not been developed to any extent. The discovery of the New Caledonia deposits aroused great interest in industrial circles, as it was thought cheap nickel was thereby assured. Of late, however, the center of interest has moved from nickel silicate and New Caledonia to nickeliferous pyrrhotite and to the Sudbury District in the Canadian province of Ontario. The interest attaching to this district is due, not to the discovery of a new mineral or of nickel in a new association, if we except the occurrence of small quantities of platinum arsenide in the Sudbury ore; it is due to the richness of the ore and to the vast extent of the deposits.
Attention was first attracted to these by reason of the considerable masses of rich copper pyrite found close to the surface, and it was as a region of copper ore that Sudbury first became famous. At the depth of a few feet, however, the rich copper ores were found to be underlaid by pyrrhotite, which occurs in large lens-shaped deposits in an extensive belt of diorite. Scattered through the pyrrhotite is copper pyrite in threads, in mere specks, and in masses from the size of a pea to pockets containing several tons. The nickel contents of this pyrrhotite vary considerably. Scarcely any of it is entirely free from nickel, but the percentage varies from a trace to as much as eight or nine per cent.
An idea of the average value of the ore, and of the amount of nickel the district is capable of affording, may be gained from the particulars of the smelting operations of one of the companies that are working in this district to the end of December, 1889. One furnace ran 259 days and produced 3,849 tons of matte, said to average thirteen per cent of nickel and eighteen per cent of copper. A second furnace in 73 days produced 1,210 tons of matte of equal richness. In other words, 41,000 tons of ore produced matte containing 650 tons of nickel, and which was associated with 910 tons of copper, thus showing that the ore smelted averaged about one and a half per cent of nickel together with two and a quarter per cent of copper. All the nickel produced in this district finds a ready market, being used principally in the manufacture of guns and armor plate. It thus appears that the discoveries of the extensive Canadian deposits of nickel, and of the valuable qualities of nickel steel, are complementary one to the other.