An extremely rare failure, dissimilar metals corrosion may
result when joining two metals with differences in solution
potentials together in the same solution. One metal has a marked
tendency to corrode in preference to the other, and under certain
fluid conditions the less noble metal corrodes at a higher
rate. Dissimilar metals corrosion is usually greatest near
the joining of the two metals. Since most sucker rod materials
are compatible, this failure is seldom seen.
