Preparation And Research On Performance Of Ag/AgCl Electrodes For Marine Environment

Marine electric field measurement is the basis of marine resources and seabed topographic detection,and measuring electrodes are the key components of marine electric field measurement.It is important to prepare the electric field electrode.Based on the existing marine electric field measurement technology,Ag and AgCl are used as the main raw materials to study the micro-morphology of the powder raw material and the influence of the preparation process on the electrode performance.Based on the measured data of powder microscopic properties and electrode properties,an Ag/AgCl electrode for marine electric field measurement was prepared.The main research contents are as follows.Firstly,the physicochemical characteristics of the mixed powders constituting the electrodes were studied and optimized.The commercially available AgCl powder was treated by hot drying method,vacuum freeze-drying method and grinding&sieving,the obtained powder is analyzed and characterized.The powder obtained by vacuum freeze drying and grinding&sieving has the best performance,the dispersibility is good and the particle size is less than 3 ?m;the mixed powder is uniformly mixed by mechanical stirring method,and the mechanical stirring can improve the performance of the powder.The mixed powder prepared by using the secondary freeze-dried AgCl powder as the raw material has the best performance.Secondly,the electrode calcination and the overall bearing process are optimized.The mixed powder was tested by DTA-TG to determine the maximum temperature of the electric furnace,the temperature is 390 °C,410 °C,430 °C,440 °C.Calcined electrode and the external wire were connected by a bonding method which nearly have no damage to the electrode and the wire,then it was assembled with a laboratory-made electrode shield,a self-made electrode was obtained.Thirdly,the properties of the self-made Ag/AgCl electrode were tested.The potential difference and stability,active response and electrochemical noise of the self-made electrode were tested,all of them have an effect on the performance of the electrode.The results showed that the ratio of the mass of freeze-dried once AgCl and the nano-silver was 2:1,and the binder content was 2%,then calcination at 430 °C,which has the best performance;the self-made electrode is stable for 15 days and 155 days in seawater with constant temperature of 5 °C,and the potential difference drift values were respectively 0.041 mV and 0.0344 mV.All the self-made electrode pairs can normally restore the electric field waveform under the corresponding frequency conditions.The electrochemical noise of 70.59 % of the electrode pairs reaches the index requirement at 1 Hz.Finally,the suitability of the marine electric field of the self-made electrode pair was tested.Nine pairs of electrodes whose performances meet the requirements of the index were selected for sea test.After the sea test,the active response of eight pairs of electrodes was normal,and the electrochemical noise of one pair of electrodes reached the index requirement.In this paper,the electrode that meets the requirements of marine electric field testing is obtained by optimizing the electrode preparation process.