Preparation of electroconductive aluminum-silicon oxide ceramic sensors modified with silver and bismuth nanoparticles

Abstract

AbstractCurrently, to provide complete information on measuring is one of the most essential problems for measuring devices. In order to obtain electrodes for recording of cardiac micropotentials in a wide range of frequencies, a process for modifying of the aluminum-silicon oxide ceramic matrix with bismuth or silver nanoparticles was investigated. It was found that when impregnating aluminum-silicon oxide ceramics with aqueous or organic solutions of the silver compounds with subsequent drying and calcinations, both the total amount of silver and its distribution over the thickness of the sample essentially depend on the nature of the silver precursor solution. Thus, when impregnating the aluminum-silicon oxide ceramics with an aqueous solution of silver nitrate followed by its reduction with formic acid, the silver content in the ceramic matrix does not exceed 15% and it is mainly distributed in the near-surface layer. The highest degree of impregnation (39%) and uniform distribution of silver throughout the volume of the sample are achieved by treatment of the ceramic matrix with a branched silver carboxylate (silver caprate) solution containing 250 g/L Ag, followed by drying and calcination of the samples at 250°C. It was shown that bismuth-containing electroconductive ceramics can be obtained by its impregnation with a solution of bismuth formate or caprylate followed by its calcination in vacuum at 280°C. The results of the study showed that the ceramic sensors modified with silver nanoparticles have a direct current drift of less than 5 nV/s while the noise level does not exceed±200 nV, which allows development of the measuring apparatus from 300 nV.