raua ja nikli sulam (sisaldab üle 30% Ni) mis leiab kasutust rauasulamite legeerimisel; madalama niklisisaldusega sulam on tuntud nikkelterasena (vt ferrosulam), a master alloy iron and nickel (more than 30% Ni), used as an alloying addition in steels (see: ferroalloy)