Influence of Antimony on the Structure and the Degree of Hydration of the Anodic PbO2 Layer Formed on Pb‐Sb Electrodes

Abstract

The Pb‐Sb alloy consists of α‐Pb crystals and eutectic phase. On anodic polarization of Pb‐Sb electrodes in these phases are oxidized forming and lead oxides: , , as well as , , . The potential regions of formation of the above phases have been determined through x‐ray diffraction analysis as well as their stability and the effect of antimony on the boundaries of these potential regions. It has been established that antimony facilitates the appearance of a potential region between 0.8 and 1.2 (1.3) V in which nonstoichiometric is formed. This leads to a shift in the potential of oxidation of to from 1.0 V for Pb electrodes to 1.2 (1.3) V for Pb‐Sb ones. The reason for the formation of (which has the same crystal structure as that of or is amorphous) has been investigated. It has been established that antimony has a catalytic effect on the reaction and slows down the rate of reaction . It has been proven experimentally that antimony increases the degree of hydration of lead dioxide from 10% (for Pb electrodes) to 30% (for Pb‐20% Sb electrodes). This leads to the formation of elastic elements in the structure of the corrosion layer which, in their turn, reduce cracking of the corrosion layer.