Sensors measuring oxygen activity in melts: Development of impedance method for“in-situ” diagnostics and control electrolyte/liquid-metal electrode interface

An impedance method for periodic“in-situ” diagnostics of the solid electrolyte/liquid-metal electrode interface during the lifespan of yttria-stabilized zirconia (YSZ)-based sensors measuring oxygen partial pressure in melts was developed. It was found that the impact of polarization effects on YSZ, stipulated by corrosive measuring environments (molten alkaline metals), is increasing with increase of the working temperature, which may lead to the appearance blocking reaction layers at the electrolyte/liquid-metal electrode interface. The proposed impedance method allows obtaining necessary information about the electrolyte/liquid-metal electrode interface and about the character and the level of polarization of the liquid-metal electrode.