Fragilisation_hydrogeneBlistering related to excessive cathodic protection of an oil pipe collector

11- Hydrogen embrittlement   


The presence of hydrogen atoms in a metal crystal lattice can be extremely detrimental, leading to a catastrophic loss of mechanical strength and ductility.
It is generally accepted that the hydrogen is first of all adsorbed on the metal surface before penetrating the lattice, where it diffuses in ionic form (i.e. as protons).
The hydrogen atoms can have various origins the surrounding atmosphere containing hydrogen or hydrogenated compounds (H2S, NH3, H2O, etc.), electroplating processes during which the proton reduction reaction occurs, electrochemical corrosion during which the cathodic reaction is proton reduction.

Once they have penetrated the crystal lattice, hydrogen atoms can cause several types of damage.

Means of preventing blistering and hydrogen embrittlement are :

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