Monday 14 January 2013

Zinc and Zinc Alloy Applications

Pure metallic Zinc, which has the chemical symbol Zn, was first isolated by Marggraf in 1746, however brass which is an alloy of copper and zinc has been used since at least 1000BC. Zinc is in group 12 of the periodic table and reacts in a similar way to magnesium.

Zinc ore is mined in China, China, Peru and the USA, its most common ore is a sulfide called sphalerite or zinc blende. China is the world’s largest producing, responsible for about one third of the World’s production. Zinc ores are often found in combined deposits with the lead mineral, galena (PbS) and with silver ores. Only about 3 quarters of the Zinc used today is mined, the rest is recycled.

Applications for Zinc

Zinc is the 4th most common metal used today. It is used in as a pure metal, in various alloys and in certain compounds of zinc.

Pure Zinc applications

The main application for Zinc is corrosion resistance, the dip coating of iron in metallic zinc, known as galvanizing, or electrochemical application, produces a surface layer that will be oxidized first before the iron or steel. Zinc is more reactive than iron or steel and thus will attract almost all local oxidation until it completely corrodes away As the zinc is oxidized it forms a protective layer that prevents further oxidation until the layer is scratched or damaged. The underlying iron or steel is protected from corrosion until the zinc corrodes away completely, which can take many years.

This form of corrosion protection, accounts for over half of the yearly usage of zinc, and is used in many applications such as bridges, street lamps. Car bodies, guard rails and chain link fences.

Other anti-corrosion uses for zinc include connecting zinc rods to underground pipelines. The zinc cathodically protects the pipeline, by slowly corroding itself instead of the pipe. Zinc can also be attached to ship keels, propellers and rudders to provide a sacrificial protection.

Other uses for zinc metal include as an anode material for batteries, both in powdered form and as sheets of zinc.


Read the full article at original source: http://www.amazines.com/article_detail.cfm/5245995?articleid=5245995