A New Pressure-balanced Outer Reference Electrode with Oxidized Zircaloy Tube Container for Corrosion Studies in High-Temperature-High-Pressure Aqueous Solution and Its Application to obtaining Polarization Curves

A new pressure-balanced outer reference electrode with the sheath of Zircaloy tube oxidized in air at a high temperature was fabricated for corrosion studies of metals in high temperature and pressure aqueous solutions. This reference electrode is very simple in the structure and has excellent stability in potential for long period, along with easy maintenance. Using this outer reference electrode, anodic polarization curves for SUS 304, Ni and Fe were obtained in 0.05M Na2SO4 aqueous solutions at high temperatures, being compared with the results from the use of an inner reference electrode in the present study and with already publicated results. It was confirmed that the potential obtained with this newly fabricated electrode could be correctly transferred to the standard hydrogen electrode potential, adopting the equations proposed by Macdonald et al. or Bogaerts et al. This new reference electrode can be used also as the inner reference electrode by adjusting its length and the setting parts to set to an autoclave.