Iron corrosion; anti-fouling and anti-corrosive paints . and cement on ironwork set in fresh masonry, such asgirders, ties, etc., the following particulars are supplied byexperts :— Ironwork embedded in fresh mortar soon becomesattacked to a large extent, and especially portions made ofwrought or rolled iron, cast iron being less susceptible. Thereaction shows itself first in the production of a strong coat- IRON-COHROSION AND ANTI-CORROSIVE PAINTS. 27 ing of rust, which, moreover, is not confined to the surfacealone but quickly extends towards the interior. Thus rustforms, in conjunction with
Iron corrosion; anti-fouling and anti-corrosive paints . and cement on ironwork set in fresh masonry, such asgirders, ties, etc., the following particulars are supplied byexperts :— Ironwork embedded in fresh mortar soon becomesattacked to a large extent, and especially portions made ofwrought or rolled iron, cast iron being less susceptible. Thereaction shows itself first in the production of a strong coat- IRON-COHROSION AND ANTI-CORROSIVE PAINTS. 27 ing of rust, which, moreover, is not confined to the surfacealone but quickly extends towards the interior. Thus rustforms, in conjunction with the adjacent particles of mortar,regular scales, which are very brittle and chip off on bendingor exposure to the slightest shock. In addition to this theygreedily absorb water from the surrounding mass of mortar,thus contributing to the progressive destruction of the iron,a circumstance which explains why the dissociation proceedswith such rapidity that thin portions of the metal are entirelyconverted into rust within a comparatively short space of. ^^Xu^^ Fig. 10 (natural size).—Rust on rolled iron plate with defective surface, pro-duced in five minutes by the action of dilute lydrochloric acid. time. Moreover, the residual core of iron has undergone anotable alteration in its properties, the change being evidencedin particular by reduced strength as well as by brittlenessand shortness of fracture, the surface of which also oftenreveals a decided crystalHne structure. It is worthy of note that the iron increases in volumeconcurrently with the progress of the rust formation, acircumstance that may become a source of danger to thestructure, on account of the very considerable pressureaccompanying such expansion. Thus, for example, it hasbeen observed that blocks of hewn stone fitted in a defective 28 lEON-COEROSION AND ANTI-COEROSIVE PAINTS. manner with iron dowels and clamps, and set in mortar, havebeconre forced asunder owing to the cause in question, andrequired resetti
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectcorrosionandanticorr
