Composite solid electrolyte based on (Ca2+, Al3+)-infiltrated ZrO2(MgO) for direct sulfur determination in the liquid iron

Magnesium-stabilized zirconia ZrO₂(MgO)] with calcium aluminate (CaO–Al₂O₃) ceramic composite electrolyte based on (calcium ion Ca²⁺], aluminum ion Al³⁺])-infiltrated zirconia-magnesia ZrO₂(MgO)] porous backbone was prepared for direct sulfur (S]) determination in the liquid iron. Effect of amylum content on the phase composition, microstructures and mechanical properties of the composite electrolyte was detected and correlated to the electrochemical performance. The results indicated that the ZrO₂(MgO)-(CaO–Al₂O₃) composite electrolyte simultaneously inherited the mechanical and electrochemical properties of ZrO₂(MgO), and unique physical and chemical properties of CaO–Al₂O₃. The compressive strength of the composite electrolyte reached above 250 MPa and the conductivity reached up to 0.003 S/cm^-, meeting the requirements of the sensor for the electrolyte. The assembled sensor could respond to sulfur activity and showed fine response characteristics. Among the tested compositions, the composite electrolyte with 6.0 wt% of amylum added in ZrO₂(MgO) porous backbone exhibited the best properties and was more suitable for application in sulfur determination.