New reference materials for electrochemical on‐line sensors to measure steel bath composition

Publisher Website
Google Scholar
Abstract
Further efforts have to be made to develop reliable sensors for on‐line measurements in steel melts. Accurate performance of conventional sensors with a Cr‐Cr2O3 reference over extended periods is disturbed by polarization effects mainly at the solid electrolyte/oxygen reference interface. A promising way to minimize or eliminate this problem is to reduce the flux of ionic oxygen across the solid electrolyte by applying oxygen references featuring oxygen potentials close to the actual oxygen potential of the steel melt. In search of oxygen references with 's lower than that of Cr‐Cr2O3 mixtures, EMF measurements were made to determine the equilibrium oxygen pressures of the systems Cr‐CaO‐CaCr2O4, Cr‐MgO‐MgCr2O4, Cr‐Y2O3‐Y2Cr2O6, and Nb‐NbO. It is shown that the use of these reference materials enables correct on‐line measurements in fully‐killed steel baths over periods of 4 hours at least.