In presented studies resistive chlorine gas sensor with gas sensitive layer in the form of zinc oxide microrods doped with platinum was developed. The growth of active layer was carried out in water solution containing zinc nitrate (V), hexamethylenetetramine and chloroplatinic acid using the chemical bath deposition method. The structure and morphology of obtained sensors was characterized by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX). To determine the chlorine gas sensing properties Temperature-Stimulated Conductance method (TSC) was used. During the measurements sensor was tested in a reference atmosphere and an atmosphere with 2, 5 or 8 ppm of chlorine. Obtained results have shown that zinc oxide microrods doped with platinum were obtained. TSC measurements showed that developed sensor allows to detect chlorine with very good sensitivity.
The basic element of electrochemical SO2/SO3 sensors based on superionic conductors is the quality of applied material and its crystallographic structure. This paper presents structural analysis of different solid state electrolytes fabricated on the basis of Ag2SO4. It was doped with different sulfates. The structures of synthesized materials with different concentrations of sulfates are compared. Ionic conductivity strongly depends on composition of electrolyte and its crystallographic structure. X ray investigations were performed with diffractometer made by Philips using CuK(alpha ) radiation. The influence of dopants on the composition of solid solution of synthesized superionic conductors and on the change of microstructure Ag2SO4 was observed and discussed.
Thick film thermistors based on spinel-type semiconducting oxide (Mn1.6Co0.8Ni0.35Ru0.25O4) were studied. On the basis of the structure analysis (SEM observations and x-ray investigations) the computer model of the thermistor was proposed. The model was created in two steps. First, the structure of the element was simulated by generating of the spinel-type particles at the glassy matrix. Next, the model of the real structure was converted to the resistive network consisting of nodes and bonds. Various types of the resistances were considered (crystallite/grain resistance of the oxide, boundary resistance between grains, glassy layer resistance between grains). As a result the effective resistances of the random network at the different temperatures were calculated using the voltage nodes method basing on the first Kirchhoff law. Additionally the ruthenium dioxide powder was considered as a modifier. This paper presents some experimental and theoretical results obtained from the proposed model.