Properties
Zinc occurs naturally as an oxide (ZnO), sulphate (ZnSO4) and carbonate (ZnCO3) and has a relatively low melting point (419.5°C) and boiling point (907°C).
Pure zinc metal is hard, tough and flexible and produces alloys superior in strength and fluidity allowing for a wide range of applications including casting and fabrication of wrought components. Zinc is brittle at ordinary temperatures because of a tightly packed crystal structure but becomes malleable when heated making it easy to work with. The pure metal cannot be used in stressed applications due to low creep-resistance however this can be imporved with certain zinc alloys, specifically zinc-copper when titanium is added.
Used to produce a number of alloys, zinc has been blended with copper for thousands of years to produce the range of brasses. Physical properties of these alloys are subject to the proportions of zinc they contain.
Zinc is a good conductor of electricity however the most prominent characteristic of zinc is that it protects steel against corrosion. Zinc is widely used as a protective coating to iron and steel (galvanisation) or in other applications as an anode. Zinc 'self sacrifices' to protect iron, becoming the target of corrosion as it forms a complex oxide when exposed to air.
Zinc oxides are also used in cosmetics, plastics, rubber, ointments, sun screen creams, soaps, paints, ink, fertilisers and batteries.
Zinc is non-toxic and completely recyclable and around 30% of zinc used in the western world comes from recycling.
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