Abstract
The resistivity changes of porous sintered were measured in an ambient consisting of , NO, , , , and , in which the concentrations of , NO, and were varied. The adsorption behavior of the adsorbed species related to NO and was investigated by a temperature programmed desorption, and Fourier transform infrared spectroscopy. The individual contributions of the , NO, and gas species in the ambient each affected the resistivity change of at 550°C. It was considered that Sn‐O, Sn‐NO, , and sites were formed competitively on and that the adsorption and desorption behavior reached equilibrium in a short time. On the basis of the investigation results, a model of the resistivity change was proposed. The resistivity that was calculated using the model, assuming a Langmuir competitive adsorption, corresponds well with the experimental results. Thus, the model is applicable to the estimation of the resistivity change of in the atmosphere, in which the concentration of , NO, and varied. © 1999 The Electrochemical Society. All rights reserved.