Research On Preparation And Performance Of Underwater Porous Ag/AgCl Electrodes

In recent years, the disputes about territorial sovereignty and ocean resources exploitation have forced the people to explore a kind of advanced technology. Sensing technology has been widely used in underwater signal detection. Because of the complexity of the marine environment and the signal attenuation caused by water, developing of the low noise, high stability marine solid-state sensors has been imminent.This thesis firstly introduced the characteristics and purpose of different electrodes as well as the most suitable solid Ag Cl electrodes in a weak electric field, followed by detailed introduction of Ag Cl powders obtained by the solid-phase milling and the Ag/Ag Cl electrode synthesis technology by powder pressing, finally we obtained the shaped electrode main body and test the performance. Comparative study on different techniques and the performance of the prepared electrodes were conducted, which involves the technology as following several aspects: mixing silver chloride and silver powder by taking different milling time, being formed by different pressure and adding different pore-forming agent to increase the porosity. Also it was found that the self-noise of electrodes was related to the actual area involved in the reaction. Actual area includes not only the outer surface of the electrode, but also the porosity which the electrolyte can enter. And the preparation of porous electrodes can increase the effective area in the reaction, thus opening rate measurement is an essential step. The method we used was the medium soak method. It is concluded that the greater the opening rate, the lower the corresponding noise and the smaller the polarization difference potential. After process optimization, the electrochemical noise of the electrodes we prepared in low frequency of 1HZ was less than 3n V/?HZ), polarization difference potential between twin electrodes was lower than±1 m V and the fluctuation of the short-term stability was less than ±0.1m V. Finally we measured performance of the electrodes manufactured in different years. We found that the effective life of electrodes could reach at least more than a year.