Iron corrosion; anti-fouling and anti-corrosive paints . g off. is apparent on a more decided scale than in the previousexperiment. By pouring water once over an iron plate so as tothoroughly cover the entire surface (Pigs. 3 to 6) and thenleaving it to dry, only a very shght film of rust is produced,the colour of which is uniform, though a number of spotsare left clean and unrusted. This test results in nothingremarkable and similar effects can be seen daily. The application of concentrated hydrochloric acid, allowedto react during twenty-four hours (Pig. 8), causes the iron to 42 IRON-COEROS
Iron corrosion; anti-fouling and anti-corrosive paints . g off. is apparent on a more decided scale than in the previousexperiment. By pouring water once over an iron plate so as tothoroughly cover the entire surface (Pigs. 3 to 6) and thenleaving it to dry, only a very shght film of rust is produced,the colour of which is uniform, though a number of spotsare left clean and unrusted. This test results in nothingremarkable and similar effects can be seen daily. The application of concentrated hydrochloric acid, allowedto react during twenty-four hours (Pig. 8), causes the iron to 42 IRON-COEROSION AND ANTI-COEROSIVE PAINTS. dissolve as ferric chloride (Fig. 13). On lightly washing thesolution off with water and leaving the iron to dry in the air,a coating of rust, containing numerous contiguous rusty ex-crescences on a clean-etched surface of metal, is seen, thesewarty lumps being in places so closely packed as to simulatea crust. The colour varies from ordinary rust-red to darkbrown. The reaction of concentrated hydrochloric acid for twelve. Fig. 2G (natural size).—Thoroughly corroded iron plate : atmospheric actiou. hours (Fig. 9) produces a coherent crust, of fairly regulardepth, which has already begun to peel off. Below thisincrustation is a secondary formation of rust, so that whenthe upper crust falls off or is dissolved, a new layer will befound, which, however, takes much longer to arrive at thepeeling-off stage. When dilute hydrochloric acid is left to act for only ashort time (Figs. 10 and 11) there is formed a coherent layer of mON-COBEOSION AND ANTI-COHROSIVE PAINTS. 43 rust of a fairly UDiform dark rust-brown colour. Only in afew patches, where the surface produced by rolling has beendamaged, is the uncorroded metal to be seen. No looseningof the rust coating can be detected, a proof that it is rela-tively very thin. In two hours dilute hydrochloric acid produces thickerincrustations of rust (Fig. 14) rather browner in colour. Inthis case also there i
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectcorrosionandanticorr
