LSGMCF dense diffusion barrier preparation and electrical characteristics for limiting current oxygen sensor

Abstract

La0.8Sr0.2(Ga0.8Mg0.2)1-x(Cr0.4Fe0.6)xO3-δ(LSGMCF, x = 0.1, 0.3, 0.5, 0.7 and 0.9) and La0.8Sr0.2Ga0.8Mg0.2(LSGM) were synthesized by solid-state reaction with La2O3, SrCO3, Ga2O3, MgO, Cr2O3 and Fe2O3 as raw materials. By characterizing the phase analysis and micro-structure of LSGMCF, it was found that Cr and Fe dissolved in the main crystalline phase LSGM in a wide range. The effects of Cr and Fe concentrations on the electronic and total conductivity of LSGMCF were analyzed by Hebb-Wagner and Linear Sweep Voltammetry methods. The results show that when x = 0.9, it has better electronic conductivity and the highest total conductivity. LSGMCF(x = 0.9) and LSGM were prepared into limiting current oxygen sensor by co-pressing and co-sintering technique, and its sensing characteristics were studied. The oxygen sensor exhibits a limiting current in the range of 0–7% oxygen concentration at 730–790 °C. The limiting current is directly proportional to the oxygen concentration, indicating that it shows good sensing characteristics at different temperatures. In addition, its sensing performance has excellent stability between 0 -42h.