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The purpose of this study is to investigate the NaCl-induced
hot corrosion performances and mechanism of the Fe-Ni-Cr
alloys which were studied by means of T.G.A, metal loss and
internal penetration methods. The results show that
NaCl-induced hot corrosion of Fe-Ni-Cr alloys were
influenced by reaction temperature and the chromium- and
nickel-contents. Chloridation was the major reaction when the
reaction temperature was above the melting point of NaCl. On
the other hand, oxidation predominated the corrosion
mechanism when the temperature was below melting point of
NaCl. The volatile chlorides which were produc ed by
chloridation reaction diffused outward through pores in the
oxide scale to the regions of higher oxygen potential, where
they were then reoxidized into oxides and formed a porous bi-
layered oxide scale, consisting of an outer layer of iron
oxide and an inner layer of chlominum oxide. At the same time,
chlorides attacked alloy''s matrix and generated an
internal attacked pore-structure on the high nickel-content
alloys.
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