The most widely used alloy of zinc is brass, in which copper is alloyed with anywhere from 9% to 45% zinc, depending upon the type of brass, along with much smaller amounts of lead and tin. Alloys of 85–88% zinc, 4–10% copper, and 2–8% aluminum find limited use in certain types of machine bearings. Alloys of primarily zinc with small amounts of copper, aluminum, and magnesium are useful in die-casting. Similar alloys with the addition of a small amount of lead can be cold-rolled into sheets. An alloy of 96% zinc and 4% aluminum is used to make stamping dies for low production run applications where ferrous metal dies would be too expensive
Corrosion is deterioration of essential properties in a material due to reactions with its environment. It is the loss of an electron of metals reacting with water or oxygen. Weakening of iron due to oxidation of the iron atoms is a well-known example of electrochemistry (a branch of chemistry that studies the reactions that take place when an ionic and electronic conductor interfere) corrosion. This is commonly known as rust. This type of damage usually affects metallic materials, and typically produces oxide(s) and/or salt(s) of the original metal. Corrosion also includes the dissolution of ceramic materials and can refer to discoloration and weakening of polymers by the sun's ultraviolet light.
Most structural alloys corrode merely from exposure to moisture in the air, but the process can be strongly affected by exposure to certain substances .Corrosion can be concentrated locally to form a pit or crack, or it can extend across a wide area to produce general deterioration.
While some efforts to reduce corrosion merely redirect the damage into less visible, less predictable forms,
controlled corrosion treatments such as passivation and chromate-conversion will increase a material's corrosion resistance.