Zinc (Zamak) Alloys
Zinc is commonly alloyed with aluminum (at about 4%), and magnesium. Copper may be used as an alloying element mainly to improve wear resistance. These alloys are commonly referred to as Zamak alloys, which is an acronym for zinc, aluminum, magnesium and copper. Zinc alloys have a melting range of about 380-390°C (~ 725°F) although higher levels of aluminum can increase the melting point to as high as 480°C (~ 900°F). Low aluminum content and melting temperatures below 400°C (750°F) allow zinc alloys to be die cast using hot-chamber machines. Due to the lower temperatures and pressures at which zinc alloy is die cast, die life is significantly increased and die maintenance is reduced. And, because of the narrow solidification range of Zamak alloys, castings can be produced with very fast cycle times.
The lower die temperatures and fast cycle times require that any release agent for zinc must evaporate quickly at the die temperature. Solvent-based products are commonly used in such applications. Where longer cycle times and heavier castings are involved, water-based lubricants have been successfully used.