Self-Healing Behavior of Oxide Layer in Liquid Metal

Abstract

The dynamic behaviors of oxide layer formation, growth and self-healing in liquid metal lead (Pb) were studied by on-line monitoring with electrochemical impedance spectroscopy (EIS). The metal rod made of zirconium (Zr) was immersed to liquid Pb at 773 K as the working electrode of EIS. The capacitance semicircle due to the oxide layer formation on the rod surface was detected by EIS after the immersion for 45 hr. The increase of impedance due to the growth of the oxide layer in liquid Pb was continuously detected. The rod was taken out from liquid Pb after the immersion for 150 hr, and the oxide layer formed on the rod was partially exfoliated using lathe to simulate the damage of the oxide layer. The rod was immersed again to liquid Pb for 200 hr. The capacitance semicircle due to the self-healing of the oxide layer was recognized after the immersion for 126 hr. The self-healing of the artificially damaged area on the oxide layer was recognized by the microscopic analysis.