Some Metals of the Last Century
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ABSTRACT The Twentieth Century can be looked back upon as a period in which a number of metal alloys unknown to previous centuries were introduced Some were alloys in unusual combinations of previously-used metals, but also elements little used earlier. Some of these alloys have already had their day and exist now only in museum collections, where they may also present problems of preservation. Many metals lost their traditional applications or added entirely new ones. Elements such as uranium and the semimetals that had been of interest only to the ceramist at the start of the century are now the bases of industries unforseen only a hundred years ago. From this it is concluded that predictions for the present century are uncertain. INTRODUCTION: By examining the table showing the dates of discovery of the elements we can see that the periodic table was finally filled in, and even extended, during the twentieth century but that most of the metal elements in addition to the ones used in antiquity we now use were first identified during the century, from 1750-1850, coincident with the first industrial revolution. The industrial revolution (1750-1850): The inception of the Industrial Revolution is defined by historians as the transfer of at least half the means of production from the home, i.e., cottage industry, to the factory. In Britain, the type site, it is usually dated from about 1750. The iron industry, because of a shortage of timber, had already begun, in 1707, the shift from wood charcoal to coke for fuel, and also began supplementing scarce water power sources with steam. The greater strength of coke in the shaft furnace allowed taller shafts and larger burdens. The result was increasing quantities of smelted metal, the introduction of cast iron as a structural material, and an increase in the number of puddling furnaces (fineries) that converted cast iron to wrought iron and, in turn, the cementation furnaces that converted wrought iron into blister steel. But the production of vast amounts awaited the so-called Age of Steel. The Age of Steel (1850-): Bessemer introduced ‘pneumatic steel,’ in which his converter replaced the finery and the cementation furnace, in 1856. Shortly afterwards the open hearth was adapted to the smelting and alloying of iron. With these two developments production of ‘tonnage steel’ became possible, but required close control of composition and temperature. Heretofore quality had not derived from control of the process so much as from choosing a source of ore having little if any deleterious elements, and treating (smelting) that ore consistently in an empirically determined procedure. The beginning of process instrumentation might well be dated to Le Chatlier’s invention of the thermocouple in 1887 [1]. With the new methods of steelmaking the chemistry was experimented with, alloying elements were added deliberately and analytical techniques introduced, with an increasing control over content even though scrap metal was being recycled. The emphasis was on chemistry rather than s
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