Experimental evidence of long life lead-free oxygen galvanic sensors

摘要

In this work we present an experimental study of the lifetime of O2 galvanic sensors in KOH aqueous solution, considering bismuth, copper and antimony as the candidates for lead anode replacement in present devices. An initial accelerated ageing test in 100% O2 suggested antimony for the next stage. Further experiments have shown an accelerated ageing factor of 18, which allowed the estimation of a lifetime of more than five years for an O2 galvanic sensor based on Sb anode of large surface area. A scaling law in lifetime as a function surface area (or anode current density) was found, which agreed with electrochemical passivation studies of Sb in alkaline solutions.