Page:Experimental researches in chemistry and.djvu/73

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On the Alloys of Steel.

—first, to ascertain whether any alloy could be artificially formed, better, for the purpose of making cutting-instruments, than steel in its purest state; and secondly, whether any such alloys would, under similar circumstances, prove less susceptible of oxidation;—new metallic combinations for reflecting mirrors were also a collateral object of research.

Such a series of experiments were not commenced without anticipating considerable difficulties, but the facilities afforded us in the laboratory of the Royal Institution, where they were made, have obviated many of them. The subject was new, and opened into a large and interesting field. Almost an infinity of different metallic combinations may be made, according to the nature and relative proportions of the metals capable of being alloyed. It never has been shown by experiment, whether pure iron, when combined with a minute portion of carbon, constitutes the very best material for making edged tools; or whether any additional ingredient, such as the earths, or their bases, or any other metallic matter, may not be advantageously combined with the steel; and, if so, what the materials are, and what the proportion required to form the best alloy for this much desired and most important purpose. This is confessedly a subject of difficulty, requiring both time and patient investigation, and it will perhaps be admitted as some apology for the very limited progress as yet made.

By referring to the analysis of wootz, or Indian steel[1], it will be observed that only a minute portion of the earths alumina and silex could be detected, these earths (or their bases) giving to the wootz its peculiar character. Being satisfied a to the constituent parts of this excellent steel, it was proposed to attempt making such a combination, and with this view various experiments were made. Many of them were fruitless: the successful method was the following. Pure steel in small pieces, and in some instances good iron mixed with charcoal powder, were heated intensely for a long time; in this way they formed carburets, which possessed a very dark metallic grey colour, something in appearance like the black ore of tellurium, and highly crystalline. When broken, the facets of small buttons, not weighing more than 500 grains, were frequently above

  1. Quarterly Journal of Science, vii. 288.