Nickel base alloys and newer 6Mo stainless steels meet corrosion challenges of the modern day chemical process industries

The first major nickel alloy introduced to the industry, about 100 years ago, was a Ni-Cu alloy 400. This alloy is still widely used in a variety of industries and will continue to be used in this current century. Over the past 100 years, especially in the last 50 years, improvements in alloy metallurgy, melting technology, and thermomechanical processing, along with a better fundamental understanding of the role of various alloying elements has led to new nickel alloys, These have not only extended the range of usefulness of existing alloys by overcoming their limitations, but are reliable and cost-effective and have opened new areas of applications. This paper briefly describes the various nickel alloy systems developed during the last 100 years and comments on what the future holds for the newer alloys developed in the last 20 years and on the competition faced by these alloys in the new millennium. High-temperature alloys are not discussed in this paper.