Recently, a new nickel-molybdenum-chromium alloy (UNS N10362) was developed and commercialized for use in the chemical process and associated industries. In addition to exhibiting high resistance to hydrochloric and sulfuric acids, the alloy has proved extremely resistant to chloride-induced localized attack (pitting and crevice corrosion) and quite tolerant of oxidizing species.
In parallel developments, it has been discovered that certain molybdenum- and chromium-bearing nickel alloys (including this newly commercialized material) are amenable to age-hardening by virtue of a long-range ordering reaction that produces domains of A2B, or more precisely Ni2 (Cr, Mo). These domains form homogeneously within the microstructures of such alloys, typically doubling their room temperature yield strengths, with minimal effect upon their environmental resistance.
In this paper, the effects of age-hardening on the corrosion properties of UNS N10362 are evaluated and discussed. In particular, the effects in hydrochloric acid and sulfuric acid (with and without the presence of oxidizing species), and in ferric chloride, which is known to induce pitting and crevice corrosion, are defined.
