Iron corrosion; anti-fouling and anti-corrosive paints . action ofsmoke fumes, weak acid gases, dilute liquid alkalis, iron is left in the open air, and thus exposed to theinfluence of depositions and condensations of water, ^ rainand snow, brought about by fluctuations of temperature, itrusts, , the iron—whether wrought or cast, rolled iron orsteel—acquires a red incrustation, pulverulent when dry, IRON-CORBOSION AND ANTI-CORROSIVE PAINTS. 31 easily rubbed off, and leaving a clean surface underneathprovided the reaction has not occurred more than once andfor only a short time. If
Iron corrosion; anti-fouling and anti-corrosive paints . action ofsmoke fumes, weak acid gases, dilute liquid alkalis, iron is left in the open air, and thus exposed to theinfluence of depositions and condensations of water, ^ rainand snow, brought about by fluctuations of temperature, itrusts, , the iron—whether wrought or cast, rolled iron orsteel—acquires a red incrustation, pulverulent when dry, IRON-CORBOSION AND ANTI-CORROSIVE PAINTS. 31 easily rubbed off, and leaving a clean surface underneathprovided the reaction has not occurred more than once andfor only a short time. If, however, the deposition of wateror moisture be repeated and prolonged, then the red layersincrease in thickness, and when rubbed off leave behind themred and roughened patches, necessitating the employment ofsharp instruments, forcibly applied, before the clean surfaceof the metal can again be laid bare. By still longer exposureto the reaction, thick incrustations of rust are finally de-veloped, and when these are removed the surface of the iron. Pic. 15 (natural size).—Rust produced by dilute hydrochloric acid on ironplate with almost undamaged surface. The dark patch in the middleis where the rust has chipped ofi; and the dark line underneath showswhere the layer of rust is peeling. is found pitted with hollows of greater or smaller depth, thecleaning of the metal being then a matter of greater difficultythan ever. The author has examined a number of cast-irongaspipes which had been left in the open for several months,and found that the formation of rust had proceeded far fromuniformly, although the pipes were all exposed to preciselythe same atmospheric conditions. Many of the pipes hadacquired only a slight film of rust, whilst others were almostfree from rust on the upper side—the one most exposed to therain—though the sides were covered with coherent, but thin,layers of incrustation. Even in one and the same pipe some 32 mON-COBEOSION AND ANTI-CORROSIVE PAINTS
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectcorrosionandanticorr
