According to the study of international measures of prevention, application and economics of corrosion technologies published by NACE INTERNATIONAL IMPACT in 2016, mentioned the economic losses caused by metal corrosion is tremendous, it was 2.5 trillion US dollars globally, which accounts for 3.4% of global GDP（2013）.
Corrosion not only causes economic losses, but also often poses a threat to safety. Some localized corrosion, such as pitting or stress corrosion cracking, is often sudden and can easily cause safety accidents. For example, fires and explosions caused by corrosion leakage of oil pipelines, and the damage caused by corrosion of petrochemical equipment, which accounts for 60% of safety accidents, poses a great threat to safety.
The corrosion induced leakage from equipment and pipeline, which cause environmental pollution. Poisonous gas leakage causes a wide range of pollution, such as HS, CO, etc. The polluted soil and ocean will harm the environment for decades or even longer.
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Due to the strong adsorption of H2S, HS- and S2- on the surface of the electrode, which blocks the process of hydrogen atoms, from the reduction reaction, to form hydrogen molecules, which accelerates the diffusion of hydrogen atoms into the base metal and aggregation in defected area (inpurity, lattice, grain boundary defects, etc.). Or hydrogen atoms exist in the lattice by the form of interstitial atoms. Both situations can significantly reduce the plasticity and toughness of the material, increase the cracking sensitivity of the material, resulting in catastrophic failure of the material. The most common hydrogen damages are SSC, HIC, HB and SOHIC.
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