Ni and Cu can be mixed in any proportion to form a solid solution alloy called Monel alloy. Ni and Cu have good resistance to HF, seawater, brine and crevice corrosion. Monel alloy Ni70Cu30 is the earliest nickel base corrosion resistant alloy. It has high strength and toughness, but also has good performance of anti acid and alkali medium reduction and seawater corrosion, so it is usually used in the manufacture of conveying hydrofluoric acid (HF), saline alkali salt, neutral medium, and equipment for reducing acid medium.

Monel alloy is Ni2Cu solid solution, in which Cu is used as non oxidizing resist in Ni, which improves the corrosion resistance of Ni alloy and strengthens the alloy. The addition of C can improve the casting properties of the alloy, but at room temperature, the alloy can only dissolve 0115% of C, and the excess C will be precipitated in graphite phase. Adding 115% ~ 315%Fe can improve the casting properties of the alloy. The addition of Mn and Si can improve the mechanical properties of the alloy, especially the content of Si, which has an important influence on the mechanical and physical properties of the Monel alloy.


Monel alloy has two major categories: cast alloy and wrought alloy. The deformation of Monel alloy in the United States has more than 10 kinds, such as: Monel400, Monel, C, Monel403, Monel404, Monel, R-405, Monel406, Monel411, Monel, K500, Monel501 and Monel502, where Monel400 and MonelK500 are the common Monel alloy.