Invar (also know as Invar 36, NILO 36, Pernifer 36, and Invar Steel) is a low expansion alloy consisting of 36% Nickel, balance Iron. Invar Alloy exhibits extremely low expansion around ambient temperatures, making Invar Alloy particularly useful in applications where minimum thermal expansion and high dimensional stability is required, such as in precision instruments like optoelectronic devices, optical and laser benches, electronics, and other kinds of scientific instruments.
This alloy has been used for applications where dimensional changes due to temperature variation must be minimized such as in radio and electronic devices, aircraft controls, optical and laser system, etc.