HYDROGEN, NITROGEN, AND NOBLE GASES

Gaseous or liquid hydrogen does not interact with aluminium at any pressure. Due to their very good resistance at low temperatures, aluminium alloys have interesting applications in installations for the cooling, compression and liquefaction of this gas, as well as for the construction of reservoirs for liquid hydrogen in rockets [1]. 

During TIG or MIG arc welding, traces of lubricants used during transformation, machining and forming, as well as humidity from condensation or from the ambient air, are decomposed by the electric arc. These are sources of hydrogen that may dissolve in the liquid aluminium. 

Due to the insolubility in the solid state, small bubbles are formed in the welding seam during cooling. These pores lead to poor welding seams, which is why the zones to be welded must be carefully brushed in order to eliminate any surface contamination. Furthermore, it is necessary to work under controlled temperature and humidity 

The role of hydrogen in stress corrosion of aluminium alloys is dealt with in Section B.2.5. 

Gaseous or liquid nitrogen does not interact with aluminium at any pressure. 

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