Zinc-aluminium (
ZA)
alloys are alloys whose main constituents are
zinc and
aluminium. Other alloying elements include
magnesium and
copper. This type of alloy was originally developed for
gravity casting. Noranda, New Jersey Zinc Co. Ltd., St. Joe Mineral Co. and the International Lead Zinc Research Organization (ILZRO) were the main companies that pioneered the ZA alloys between the 1950s and the 1970s. They were designed to compete with
bronze,
cast iron and aluminium using
sand and
permanent mold casting methods. Distinguishing features of ZA alloys include high as-cast strength, excellent bearing properties, as well as low energy requirements (for melting).