Essay On Metal Corrosion

1605 Words7 Pages

Metal corrosion is its’ quiet destruction. Most of metals in nature have a trend of translate to oxides or stable compounds, except Au, Pt and other noble metals. So, there are very few pure metals in the nature. Engineering metals (Fe, Al, Cu, Mg, etc.) which are extracted from ore or oxide have a strong tendency to return to their stable state. This phenomenon that the metal change back to its metal compound and lose its original metal characteristics in surrounding environmental (such as moisture, temperature, acid, alkali, salt and other chemical substances, etc.), is called upon as corrosion. The specific hazards induced by metal corrosion include materials wasting, environment pollution caused by the metal ions dissolution and serous engineering safety accidents caused by corrosion. Cathodic protection was first developed by Sir Humphrey Davy in 1824 as a means of controlling corrosion on British naval ships. Cathodic protection is one of the most widely accepted and applied technology for engineering metal anticorrosion. It can be classified into two types: impressed current cathodic protection and sacrificial anode protection. The impressed …show more content…

Cathodic protection in reinforced concrete: Number of relatively recent developments in the application of impressed current CP to concrete structures have already been mentioned. Notable among these has been the application of ‘‘cathodic prevention’’ as a means of improving the corrosion resistance of new structures exposed to chloride laden environments. This requires cathodic current densities of only about 1–2 mA/m2 and has been used since about 1990 in Italy on pre-stressed concrete viaducts. The modest polarization needed to achieve perfect passivity obviates the risk of hydrogen embrittlement (Bertolini et al. 1993). Interesting proposals have also been made recently concerning the application of intermittent CP both in marine tidal locations, where remote anode systems in seawater might be employed

More about Essay On Metal Corrosion

Open Document