ZA alloys were initially developed for gravity casting. Their mechanical properties compete directly with bronze, cast iron and aluminum using sand, permanent mold and plaster mold casting methods. Beginning in the late 1950's and continuing into the 1970's, Noranda, New Jersey Zinc Co. Ltd., St. Joe Mineral Co. and ILZRO contributed to development of the ZA alloy group. Zinc and Aluminum are the major alloy constituents, along with other minor additions of magnesium and copper. The numbers associated with the name represent the amount of aluminum in the alloy (i.e. ZA8 has 8% aluminum). Distinguishing features of ZA alloys include high as-cast strength, excellent bearing properties, as well as low energy (melting) requirements.
Eastern Alloys manufactures the entire ZA alloy group. There are many different gravity-casting processes such as permanent mold, graphite permanent mold, plaster, and sand. In general these processes are used for low to medium volume requirements, and also as a prototyping technique.