| The metal corrosion means the phenomenon that the metal is broken down because of chemical or electrochemical reaction between the metal and its ambient medium.The direct economical loss by metal corrosion is about 1~4% of the national economy total production value. Besides, it wastes natural resource and energy source, sometimes, it also threatens personal life. The atmospheric environment is going bad with the developing industry, the metal corrosion phenomenon is also going serious, especially in coastal areas and heavy industry polluted areas.In the late century, the metal corrosion has thus been the very important research project studied by science and technology workers in the world.There are many methods to resist steel corrosion. The hot-dip corrosion resistant metal coating on the surface of steel base is an important one of them. In 1836, French chemist Sorel is the first to hot-dip pure Zn on steel products. In 1837, English chemist Grawford. H.W. is also the first to apply the patent for hot-dip pure Zn by flux method, therefore, the first generation product to resist atmospheric corrosion is introduced, and in the recent century, the Grawford method has always been adopted.But, the hot-dip pure Zn products became more difficult to meet actual needs with the worse atmospheric environment. For example, the design age of power transmission system is about 30 years, but the transmitting wire —Zn-hot-dipped steel cored Al binding wire only serves 20 years, and it even serves 8 years in the seriously eroded areas. So, it is very urgent to find better corrosion resistant metal coating to substitute the conventional hot-dip pure Zn coating.In 1939, American Armco Steel Company developed the hot-dip pure Al technology after extensively studying the property and mechanism of... |
PDF Full Text Request