Nickel-Chromium-Molybdenum. There are
many commercially available Ni-Cr-Mo alloys
today. All these alloys were derived from the
original C-alloy (N10002), which was introduced
to the market in cast form in 1932. The
more advanced Ni-Cr-Mo alloys are N06686,
N06059 (alloy 59), and Hastelloy C-2000. However,
the more common Ni-Cr-Mo alloy in industrial
applications is alloy C-276 (N10276) which
was introduced in the market in the mid-1960s.Nickel-chromium-molybdenum alloys are the
most versatile nickel alloys, because they contain
molybdenum, which protects against corrosion
under reducing conditions, and chromium,
which protects against corrosion under oxidizing
conditions (Ref 7). Figure 1 shows that C-276
has low corrosion rates both in reducing conditions
(boiling 10% sulfuric acid) and oxidizing
conditions (boiling 10% nitric acid). One of the
major applications of Ni-Cr-Mo alloys is in the
presence of hot chloride-containing solutions.
Under these conditions, most of the stainless
steels would suffer crevice corrosion, pitting corrosion,
and SCC. However, Ni-Cr-Mo alloys are
highly resistant, if not immune, to chlorideinduced
attack in most industrial applications