Hydrogen into Metal

More recently, hydrogen storage has become important, and interstitial alloys formed by incorporation of hydrogen into metals are of considerable interest. Niobium is typical of these. This metal is able to incorporate interstitial hydrogen up to a limiting composition of approximately NbH0.i-... 

Diatomic hydrogen gas can adsorb and dissociate on metal surfaces to produce atomic hydrogen [1,2]. The subsequent dissolution and diffusion of atomic hydrogen into metals can have two consequences for the performance of a... 

The entry of hydrogen into metals is promoted by various compounds, especially those involving elements from Groups VB (P, As, and Sb) and VIB (S, Se, and Te) of the periodic table. Some anions such as CN , CNS , and 1 and certain carbon compounds such as CS2, CO, and CSN2H4 also promote hydrogen entry. 

The penetration of hydrogen into metal can be measured electrochemically in an assembly of two coupled electrochemical cells with two potentiostatic circuits, according to the method of Bockris and De-... 

Absorption of a gas into the bulk of the material involves adsorption, possible dissociation (e.g. O2 to 20), then diffusion into the material. The process of injecting gas into a surface is called charging . Diffusion of gases, particularly hydrogen, into metals can be enhanced by exposure to a plasma and low energy ion bombardment. 

The last equation is related to the first gas phase studies of the solubility of H2 in iron (and other metals) generally attributed to Sieverts (Sieverts etal, 1911), who found experimentally that amounts of H2 dissolved in metal is directly proportional to the square root of the hydrogen pressure (Equation [2.4]). Various aspects related to the degradation of mechanical properties due to the entry of hydrogen into metals or alloys can also be found in Lewis (1967) and in Paal and Menon (1988). 

---