The chemical composition of the alloy is mainly composed of 30% Cu, 65% Ni and a small amount of Fe (1% - 2%). Because of the difference in chemical composition, it can have a variety of alloy grades, but there is no significant difference in corrosion resistance between them. MONEL400 alloy is more resistant to reducing medium corrosion than pure nickel, and more resistant to oxidizing medium corrosion than pure copper. MONEL400 is a deformable nickel copper nickel base alloy with excellent seawater corrosion resistance, chemical corrosion resistance and chloride stress corrosion cracking resistance. The alloy is one of the few that can be used in fluoride. It has good resistance to oxidative stress fission corrosion in hydrofluoric acid and fluorine gas medium, such as seawater and brine.