用于高温熔盐的参比电极

CHARACTERS OF PORCELAIN REFERENCE ELECTRODE IN MOLTEN SALTS

研究了用于高温熔盐的Pt|0.9Ag_2SO_4+0.1(NaK)_2SO_4|陶瓷隔膜参比电极的各种性能。以高铝陶瓷作为致密隔膜材料制成的参比电极在熔融硫酸盐中具有良好的电位稳定性、重现性和可逆性。初次使用的电极要经过一段时间的“活化”才能达到电位稳定。“活化”时间的长短随隔膜材料及其厚度的不同而异。外电流引起的极化包括:隔膜电位降、电化学极化和不对称电位,但这些极化电位能在断电后的几分钟内基本消除。

Silver/silver ion reference electrodes with alumina,quartz,and other porcelain diaphragms conductive to sodium and potassium ions have been studied.The reference electrodes,used in electrochemical measur- ement in molten sulfate salts at above 700℃,have excellent reproduci- bility,long-time stability and reliable reversibility.They.have to be immersed into the melt for duration of activation before a stable potential is reached,and the properties of the electrode with thin diaphragm are better than those with thick diaphragm.Further investigations on electro-chemical characters of the electrodes indicate that the polariza- tionp otential caused by galvanostat polarization results from resistance of the diaphragms Rp,asymmetrical potential,and electrochemical reaction resistance.The polarization potential will disappear within 10 minutes after the circuit is broken.