In the materials selection process for corrosion
applications, the chemical composition of the
alloy is generally the most important factor that
an engineer considers. However, examples given
in this article demonstrate that the metallurgical
condition or microstructure of a particular nickel
alloy is also a very important factor. For the same
overall chemical composition, the corrosion rate
of the same alloy can vary several orders of magnitude,
depending on its particular microstructure.
The most important metallurgical factors
that need to be considered are second-phase precipitation
by thermal instability and the presence
of CW. The latter is especially important in cases
where SCC may be expected.