Kinetics and Mechanism of Hydrogen Diffusion in Hydrides of Titanium, Zirconium and TiNi_0.5

Abstract

Diffusion / Metalle / Wasserstoff in MetallenHydrides of titanium and zirconium formed during cathodic polarization in acid solutions were investigated by the "N nuclear reaction method. Hydrogen depth profiles obtained in this way give informations about the hydrogen concentration in the metal, allowing to determine diffusion coefficients and therefrom to study the absorption of hydrogen by the metal lattice and the kinetics of the hydride layer growth. The mechanism was studied using Ti single crystals. The hydrogen diffusion was found to depend on the crystal orientation.

Kinetics and Mechanism of the Hydrogen Evolution Reaction on Titanium in Acidic Media

“…where Habs (x = 0) refers to absorbed hydrogen atoms just inside the electrode. According to Brauer et al (22), absorbed hydrogen atoms do not permeate significantly into the bulk of the metal, but, instead, concentrate in the near surface region in the form of a hydride layer having a concentration of 63 atom percent hydrogen (Tills.65). Further absorption simply results in an increase in the thickness of the TiH~.6s layer by diffusion of hydrogen atoms through the hydride to the hydride/metal interface.…”

Kinetic Investigation of the Ti-H System by a Molten Salt Electrochemical Technique

“…9 They give the self-diffusion coefficient of hydrogen in metals, which corresponds to jump frequency of hydrogen atoms. The gas-volumetric method, 10-12 nuclear physics, 13,14 Gorsky effect measurement, 15,16 and the electrochemical method [17][18][19][20][21][22] give the chemical diffusion coefficient of hydrogen in metals, which is crucial when considering practical applications. …”

Etude experimentale du vieillissement de la composition pyrotechnique: Zirconium-chromate de plomb

“…Examinons les r6sultats exp6rimentaux & la lumi+re de ces trois points : --Les analyses en ESCA et thermod6sorption ont montr6 que le zirconium d'origine n'&ait pas le m&al pur mais qu'il contenait une forte proportion d'hydrog6ne et pr6sentait une couche superficielle oxyg6n6e peu 6paisse (probablement, car non d6tect6e en thermoluminescence). Ce sont donc un ou plusieurs COURNIL, RAMANGALAHY: ETUDE EXPERIMENTAL DU VIE1LL1SSEMENT t91 compos6s de formule globale Zr l_x_rOxHr qui subissent le vieillissement des l'ambiante et r6agissent avec le chromate de plomb ~ haute temperature; des solutions solides Zr, H [16,17] et Zr, O [18,19] sont effectivement bien connues ainsi que des groupements hydroxyles superficiels.…”