Determination of Hydrogen Content and Dehydrogenation in Molten Aluminum by Concentration Cell Method

doi:10.15541/jim20150527

Abstract

Abstract:

The CaZr_0.9In_0.1O_3-α proton conductor was prepared by solid reaction method with high purity and small particle size. Two types hydrogen sensors and pump based on the proton conductor were fabricated for monitoring the hydrogen content and dehydrogenation in molten aluminum at 760℃. The electromotive force (EMF) and time of hydrogen sensor with the inverted-U electrolyte tube followed a smooth curve in which the EMF tended to be stable after about 13 min whose sensing performance was superior to that with the upright-U electrolyte tube. The sensor EMF increased with the pressure or flow rate of referent gas according to Nernst equation. The equilibrium time of EMF increased and the transferring resistance between the Pt electrode and proton conductor’s transfer resistance decreased with the flow rate of reference gas. Therefore, inverted-U type tube and flow rate value of reference gas were very important to acquire the sensitive and accurate hydrogen content values in molten aluminum. In addition, hydrogen pump based on concentration cell had feasibility and actual using value for the dehydrogenation of molten aluminum.

Key words: proton conductor, reference gas, concentration cell, hydrogen pump, hydrogen sensor, impedance spectrum

CLC Number:

TB321

WANG Dong, LIU Chun-Ming, LI Sheng-Li, LI Wei-Juan, CHEN Shu-Jiang, YANG Bo-Wei. Determination of Hydrogen Content and Dehydrogenation in Molten Aluminum by Concentration Cell Method[J]. Journal of Inorganic Materials, 2016, 31(5): 505-509.

Figures/Tables 9

Fig. 1 XRD pattern of the mixed powders after calcinated at 1400℃ for 8 h

Fig. 2 Diagram of structure of hydrogen sensor with inverted- U electrolyte tube

Fig. 3 EMF of hydrogen probe with inverted-U (a) and upright-U (b) electrolyte tube

Fig. 4 Dependence of EMF on different pressure of gas

Fig. 5 Dependence of EMF on different gas flow rates

Fig. 6 Dependence of equilibrium time of EMF on different gas flow rates

Fig. 7 Impedance spectra (a) and equivalent electrical circuit (b) obtained from hydrogen sensor (20 mL/min of flow rate of reference gas)

Fig. 8 Dependence of impedance spectra on different gas flow rates Gas cylinder pressure 0.12 MPa (a) and 0.20 MPa (b)

Fig. 9 Relationship between hydrogen content by extracting or gas carrying hydrogen and time at 760℃

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