Electrochemical Method for Controlling the Interfacial Oxygen in Molten Fe with ZrO2 Based Solid Electrolyte

A Phenomenological Investigation on the Control of Oxides at the Interface Using an Electrochemical Cell

“…The oxygen partial pressure at the interface between molten Fe alloy and MSZ is controlled by an external electric potential as previously dis- cussed in detail elsewhere. 7) In Fig. 2, the dash lines are the critical super-saturation line by Suito et al [23][24][25] using of an EMF method and the equilibrium line between aluminum and oxygen determined by previous researchers.…”

“…However, in a recently published work elsewhere by the present author, 7) the interfacial oxygen concentration between molten Fe and ZrO 2 based solid electrolyte could be controlled using an externally applied DC voltage. An interface oxygen concentration of below 3 ppm could be obtained without significant changes in the bulk oxygen concentration.…”

Influence of Basicity on Anodic Reaction in CaO-SiO2-Al2O3Melts

“…Electrochemical research on the anodic reaction of free oxygen ions has been continuously pursued to determine the potential of molten oxides as electrolytes in various electrochemical applications, namely, molten oxide electrolysis (MOE), [2][3][4][5][6][7][8][9][10][11][12] direct current electro-slag remelting (DC-ESR), 13 and electrorefining. [14][15][16][17] Since basicity as a measure of oxygen ions in molten oxides is a fundamental index for defining the equilibrium state of chemical reactions in molten oxides, extensive research has been carried out using basicity measurements to define the chemical potential of oxygen ions in molten oxides qualitatively. However, it is difficult to directly evaluate the activity of free oxygen ions because it is impossible to experimentally measure the chemical potential of ionic species in solution due to the constrain of electro-neutrality.…”

Investigation on the Decomposition of Al2O3 Using an Electrochemical Method

“…These preliminary experiments allow the fundamental understanding of the rate controlling steps of transported oxygen species through the electrochemical cell. Based on previous studies to determine the rate-controlling steps of deoxidation processes, [9][10][11] there are five steps as shown schematically in Fig. 1 …”

“…[5][6][7] Fischer and other researchers reported that the degree of deoxidation possible from the use of electromotive force (EMF) methods in liquid metals was limited owing to the slow bulk diffusion of oxygen. [8][9][10] Kim et al 11) reported that the local interfacial oxygen concentration could be kept below 3 ppm by applying an external voltage using a ZrO2-based solid electrolyte at high temperatures and showed the interfacial oxygen concentration is a major factor in the formation of oxide inclusions. In other work regarding thermodynamic relationship between aluminum and oxygen in molten Fe, Fruehan 12) and Dimitrov et al 13) were able to analyze the activity of oxygen in a Fe-Al-O alloy using galvanic cells and found to coincide with the thermodynamic reaction mechanisms with soluble aluminum.…”