Corrosion and precipitation of corrosion products at an electrode of an
electro-magnetic flow meter and in a narrow channel of an electro-magnetic pump
(EMP) for lead bismuth (Pb-Bi) flow was investigated by means of metallurgical
analysis. The roughened surface of inlet pump core at the entrance of EMP flow
channel was observed, which indicated the occurrence of the so-called
corrosion/erosion. In the same time, corrosion products were precipitated on the
surface of the electrode and the outlet pump core. Localized corrosion/erosion and
precipitation of corrosion products were observed by means of SEM/EDX analysis for
their cross sections. The surface condition was different from each other depending on
the place. The precipitation products were made of double-layers, that is, an outer
layer and an inner layer. The inner layer (diameter range of 0-20 ~tm) contained Fe in
the fraction of 99wt%, and the outer layer (diameter range of 20-40 ~tm) contained
Pb-Bi in the fraction of 10wt%. The double layer structure might be caused by
difference of precipitation period. These lumps of the precipitation products could be
the cause of the channel plugging.