Measurement of oxygen potentials in Ag-Pb system employing oxygen sensor

Accurate and instantaneous analysis of dissolved nonmetallic or metallic sp ecies in molten metals at elevated temperatures using an online electrochem ical sensor is important for continuous process control during metal refini ng and alloying operations in metallurgical industries. In this article, th e application of long-life, solid-state electrochemical sensors for oxygen has been demonstrated to measure the oxygen potential as a function of the lead concentration in a molten Ag-Pb system at 1323 K. Yttria-stabilized zi rconia (YSZ) in the form of one end-closed tube 20 mm long, 3 mm inner diam eter, and I mm wall thickness has been used as a solid electrolyte in the o xygen sensor. Electromotive force (EMF) of the solid-state electrochemical cell (-)Pt, Ni-NiO//YSZ//OAg-Pb, Mo(+) has been measured at 1323 K. The ref erence electrode consisted of Ni + NiO biphasic mixture; the working electr ode was composed of a molten Ag-Pb alloy of varying concentrations of lead. The concentrations of lead in silver ranged from 0.02 to 10.20 wt pet. Sam ples of the molten alloy were drawn after each addition of Pb to Ag and ana lyzed by induction coupled plasma (ICP).