Data by Alloy

Because of the Mears effect (wire corrodes faster per unit of area than more massive materials), galvanized wire corrodes some 10-80% faster than galvanized sheet (see Table 2.13 also see the series of Haynie et al. papers for explanations related to deposition rates of sulfur dioxide), and thin wire corrodes faster than thick wire. 

The life of rope made from galvanized steel wires is, however, greater than that of the individual wires (Schikorr, 1943-1944 ASTM, 1956). Schi-korr explains this by pointing out that the parts of the wire that lie on the outside are corroded more rapidly and, when the zinc film is penetrated in 

V Ames, Iowa. California (rural atmosphere) a State College, Pa. (rural atmosphere) o Bridgeport, Conn, (urban atmosphere) 

The cathodic protection effect of zinc has been disputed by several authors (Bablik, 1950 Klas and Steinrath, 1956 Elze, 1959). There are certainly cases in which this effect does not occur—for instance, on zinc-free zones more than 2 mm wide (Fischer and Barmann, 1940 Spindler, 1958), having a high electrical resistance of the circuit (which often occurs in the atmosphere when only a thin layer of pure water is present), since an adequate preventive electric current cannot then flow. 

Outdoor exposure tests by the Dutch Galvanizing Institute showed that on galvanized panels with 70-80 pm zinc scratched with widths up to 5 mm, no rusting took place after 8 years of weathering in an industrial-marine climate. Similar tests were made on cut galvanized rebars (diameter 6-20 mm), exposed for 5 years. On the 6-10 mm diameter bars, no rust appeared. On the 20 mm diameter bars, the cut surface showed a uniform, light brown layer of rust. However, the ru.st had not undercut the zinc coating. 

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