Methane Formation of Decreased Volume in the Structural Defects of the Hydrogen Enriched Metals

Issue 2(76) 2015
Pages 56-62

G.I. Suranov, A.A. Latyshev

Ukhta state technical university

Keywords: defects, model, crack, trap, charged species, hydrogen, methane, electrolytic hydrogen absorption, test, gas, rarefaction, diffusion, discontinuity flaw

Defects in the structure of metal (the discontinuities, cracks, dislocations) are considered as magnetic traps for hydrogen and the admixture elements whose motion is determined to the laws of the motion of the charged particles in the magnetic field. This confirms the autograph of hydrogen in the hole (model of crack) cut out on the surface of steel specimen.
In the process of the electrolytic hydrogen enrichment (absorption) of cast iron models is formed not only methane but also other homologues of hydrocarbon (from ethane to the
hexane). During the prolonged storage, the content of methane in gas sample is increased
(to two orders and more). This creates rarefaction in the capacity.
Interaction of hydrogen with carbon on the surface of defects was observed on the model of the crack in the form of plastic capacity (bottle) into which the sample of the gas is separated during the hydrogen absorption by materials. Since methane is formed with the decrease of volume, the rarefaction is created in the bottle, its plastic walls are deformed, the level of hydro lock is risen, air enters. Rarefaction in the defects contributes to the diffusion of hydrogen and other gaseous elements and admixtures, and it determines the duration of incubative period up to the beginning of the irreversible change in the mechanical properties (embrittlement) of the absorbing hydrogen materials.