Electrodes, bismuth heated

The results of the present work may be applicable for diagnostics of oxygen sensors at more complicated applications, such as measurement of oxygen activity in liquid sodium, lithium, or lead-bismuth heat carriers for atomic power plants. Corrosion and mass transfer in nonisothermal lead-bismuth circuits with temperatures of a heat carrier of 300-500°C do usually occur at a concentration of dissolved O2 of 10 - 10 mass %. The proposed impedance method is developed for determining the level and the character of polarization at the electrolyte-electrode interface, which ensures a continuous oxide protection of materials against corrosion by means of zirconia sensors in all tanperature regimes of exploitation of liquid-metal circuits. 

Prom an "old sample" of thorium nitrate (one in which the thorlxim daughters are in equlllbrlxom), 1 gram la weighed out and dissolved in 20 to 25 ml 0-5 N hydrochloric acid. The requisite amount of standard bismuth solution (> 0.2 mg) is pipetted into the electrolysis solution which is heated in a water bath to 80-90°C. Clean platinum electrodes and a calomel half-cell are inserted and the electrolyzing current and a mechanical stirrer are switched on. The current is increased until a potential of 0.25-0.30 volte relative to the saturated calomel electrode is attained and the plating is continued for 25 minutes. 

Bismuth electrodes have been proposed as a substitute for mercury electrodes. A bismuth film on the surface of a heated carbon paste electrode indeed proved useful for stripping analysis of lead, cadmium and zinc traces [34]. An example belonging to the next chapter, i.e. analysis of DNA bases at a heated carbon paste electrode after adsorptive accumulation, also can be considered to be a kind of stripping analysis [35]. 

Jacobsen M, Duwertsee H, Wachholz F et al (2010) Directly heated bismuth film electrodes based on gold microwires. Electroanalysis 22 1483-1488... 

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