| 摘要 |
PURPOSE:To obtain a highly stable indicator electrode with a high sensitivity, by using a low melting point metal in liquid, in stead of dangerous mercury. CONSTITUTION:A metal cup 2 for fixing sensitive surface metal comprising material such as gold, copper and zinc applicable on sensitive surface metal is mounted at the tip of an electrode holding tube 1 comprising a chemical resistant and electrically insulating material. The metal cup 2 is coated with a low melting point metal and an alloy thereof to form a sensitive surface 3. A heater 5 keeps the sensitive surface 3 above the melting point by the temperature detected with a thermistor 6 through a controller. A silicon foil 9 helps transmit heat evenly to the metal cup 2. As the sensitive surface metal is used in liquid, it provides a higher hydrogenation voltage as compared with that in solid. Being amorphous, it also makes deterioration hard to occur locally with a high resistance to acid, alkali or the like and a high fluidity.
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