POTENTIOMETRIC SENSOR USING STABILIZED ZIRCONIA FOR CHLORINE GAS

A new type of solid-electrolyte gas sensor for chlorine in an O-2-cont aining atmosphere has been fabricated by combining an MgO-stabilized z irconia tube with an auxiliary phase containing metal chloride. The se nsor gives fairly good sensing characteristics to 1-100 ppm Cl-2 at 55 0-650 degrees C, with the e.m.f. response changing linearly with a cha nge in the logarithm of the Cl-2 concentration. With a multicomponent auxiliary phase of BaCl2-KCl-MgO, the times for 90% response and 90% r ecovery on switching between 4 and 40 ppm Cl-2 at 550 degrees C are 6 s and 2 min, respectively. The e.m.f. response to Cl-2 is hardly influ enced by coexistent CO2, while it shifts significantly in the presence of water vapour.