Diffusivity and solubility of oxygen in solid palladium期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

Diffusivity and solubility of oxygen in solid palladium

Authors:	J Gegner G Hörz R Kirchheim

Affiliation:	1.SKF GmbH,Abteilung Werkstoff-Physik,Schweinfurt,Germany;2.Institut für Werkstofftechnik,Universit?t Siegen,Siegen,Germany;3.Max-Planck-Institut für Metallforschung,Stuttgart,Germany;4.Institut für Materialphysik,Georg-August-Universit?t G?ttingen,G?ttingen,Germany

Abstract:	The solid solubility c _O of oxygen in palladium in equilibrium with gaseous oxygen has been determined from absorption-desorption experiments for temperatures T of 1123 and 1173 K and oxygen partial pressures $p_{{{\text{O}}_{2} }}$ between 2.7 × 10³ and 4.0 × 10⁴ Pa. The relationship between c _O, $p_{{{\text{O}}_{2} }}$ and T is given by $c_{\text{O}} = a\sqrt {p_{{{\text{O}}_{2} }} } { \exp }( - \Updelta H_{\text{s}} /RT)$ , where R = 8.314 JK⁻¹ mol⁻¹ is the universal gas constant, ΔH _s = −13.55 kJ/mol denotes the heat of solution of oxygen in palladium and the constant a amounts to $4.26 \times 10^{ - 5} \,{\text{at.}}\% /\sqrt {\text{Pa}}$ or $6.41 \times 10^{ - 8} \,{\text{wt}}\% /\sqrt {\text{Pa}}$ . The diffusion coefficient D _O of oxygen in solid palladium has been determined by incomplete isothermal internal oxidation of Pd–Fe alloys using the data on the oxygen solubility in palladium. The temperature dependence of D _O obeys the Arrhenius equation D _O = D ⁰ exp(−E _d/RT) with pre-exponential factor D ⁰ = 2.33 × 10⁻⁷ m²/s and activation energy of diffusion of oxygen in palladium, E _d = 102.76 kJ/mol

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