Corrosion of Nickel Alloys

A distinction is often made between those alloys that are primarily used for high-temperature strength, commonly referred to as superalloys, and those that are primarily used for corrosion resistance. High performance alloys are defined, in the present context, as Ni, Ni-Fe and Co base alloys able to operate at higher temperatures than 550^oC and high pressures. Fe, Co and Ni are transition metals with consecutive positions in the Periodic Table. The relative order of abundance decreases as Fe, Ni, Co.

The Fe-Ni-base high performance alloys are an extension of stainless steel technology and generally are wrought, whereas Co-base and Ni-base high performance alloys may be wrought or cast depending upon the application or composition involved. Appropriate compositions of all high performance alloy base metals can be forged, rolled to sheet or otherwise formed into a variety of shapes. The more highly alloyed compositions normally are processed as castings. Typical high performance alloys have moduli of elasticity around and above of 200 Gpa. The principal microstructural variables of high performance alloys are [30]:

To find much more on nickel based alloys consult the plentiful Nickel Development Institute site.