Evaluation of sintering time effect on the microstructural changes and electrochemical behavior of silver electrodes in the environment of silver-zinc cells

In this study, effects of sintering time on the microstructural changes and electrochemical behavior of silver electrodes in the environment of silver-zinc cells was investigated. For this purpose, initially four Ag electrodes (positive plate) with composition of 95 wt% silver oxide, 4.9 wt% carbon powder and 0.1 wt% resin by powder metallurgy method was prepared. Then, four silver electrodes were sintered for 5, 10, 15 and 20 minutes at temperature 500°C. Potentiodynamic polarization and electrochemical impedance spectroscopy methods were used in the 1.4% KOH solution to evaluate the polarization resistance of Ag electrodes. Scanning electron microscopy was used to examine the microstructures of electrodes and point analysis was accomplished by EDX method. Electrochemical tests results showed that with increasing sintering time, polarization resistance of silver electrodes reduced in the KOH solution. SEM images were showed that with increasing sintering time, the amount and size of apparent pores increased in the electrodes. Also, point analysis results has implies on reduction carbon and oxygen in electrodes with the increasing sintering process time.