Light, Safe, Environmentalist

Aluminium

Found in the form of bauxite ore in the nature, aluminium is one of the most prevalent elements available in the world. It is extracted through separation by means of electrolyte method. Pure aluminium is a soft metal, but their alloys are approximately up to 15 times resistant as their pure state. It weighs around as heavy as one third of steel or copper. It is easily malleable, machinable and shapable. It has a very high corrosive resistance. It is not toxic or magnetic. Aluminium is an eco-friendly metal and can be recycled indefinitely. The energy used to recycle it is nearly 5% of the energy needed to produce it initially. It is used in the making of millions of different products in various branches of the industry and has a very important role in the global economy. It is an indispensable item in automotive, aviation and defence industry requiring lightness and high-resistance properties. It is also widely used in the construction and furniture industry in which aesthetics is given a particular importance.

History of Aluminium

“We prefer aluminium is to build a better world”

History of Aluminium

Although Friedrich Wöhler is known to be the first person to decompose aluminium by mixing   anhydrous aluminium chloride with potassium in 1827, it was actually produced two years before that date in an impure form by Hans Christian Øersted, a Danish physicist and chemist. Therefore, the name of Øersted is mentioned as the inventor of aluminium in chemical literature. French, Henri Saint-Claire Deville improved the method of Friedrich Wöhler in 1846 by using sodium instead of potassium which was more expensive

In 1886, an American, Charles Martin Hall, lodged a patent application towards the production of aluminium by means of an electrolyte procedure. However, French Paul-Héroult, completely unaware of the invention of Hall, developed the very same method in Europe in the same year. Therefore, Hall-Heroult procedure, named after the names of the two scientists, is the basic method used today in the production of aluminium from ore.

Basic Properties

Atom Number: 13
Element Series: Metals
Group, Period, Block: 13, 3, p
Atomic Weight: 26,9815386 (8) g / mol
Electron Sequence: What 3s2 3p1
Electrons per Energy Level: 2, 8, 3

Physical Properties

State of Matter: Solid
Density: 2,70 g / cm³
Density in Liquid State: 2,375 g / cm³
Melting Point: 933.47 ° K (660,32 ° C)
Boiling Point: 2792 ° C (2519 ° C)
Melting Temperature: 10.71 kJ / mol
Evaporation Temperature: 294,0 kJ / mol
Heat Capacity: 24,2 J / (mol • K)

Atom Features

Crystal Structure: Surface centred cubic
Oxidation Levels: (3+)(amphoteric oxide)
Electronegativity: 1.61 Pauling’s scale
Ionization Energy: 577,5 kJ / mol
Atomic Radius: 143 pm
Atomic Radius (hes.): 118 pm
Covalent Radius: 118 pm

Other Properties

Electrical Resistance: 26,50 nΩ • m (20 ° C)
Thermal Conductivity: 237 W / (m • K)
Thermal Expansion: 23.1 •m / (m • K) (25 ° C)
Sound Speed: 5000 m / s (at 20 ° C)
Mohs Hardness: 2,75
Vickers Hardness: 167 MPa
Brinell Hardness: 245 MPa




Alloys

Mechanical, physical and chemical properties of aluminium alloys vary according to the elements and microstructure of the alloy. Major alloy elements added in aluminium are copper, manganese, silicon, magnesium and zinc. Aluminium alloys are divided into two: forged alloys and cast alloys. Forged alloys have a good plastic deformation capability and they can easily be shaped. Heat treatment can be applied to a great majority of the aluminium forged and cast alloys. According to U.S. aluminium association,  aluminium forged alloys are classified with four letters. This classification  is as follows:

1XXX: Pure aluminium: Generally used in the electrical and chemical industry.

2XXX: Al-Cu Alloys: The basic alloy element is copper. Other alloy elements, particularly magnesium, may be present; it is widely used in the aerospace industry where high strength is required.         

 

3XXX: Al-Mn Alloys: The basic alloy element is manganese. It is used in pipes, fluid tanks and architectural applications.

4XXX: Al-Si Alloys: The basic alloy element is silicon. These are the alloys with a low thermal expansion coefficient and high wear and corrosion resistance. It is used in the production of welded structures, plate production, auto part manufacturing.

5XXX: Al-Mg Alloys: The main alloy element is magnesium. The higher the ratio of magnesium, the higher the hardness and strength but the lower the ductility. Since it has high resistance to marine corrosion, it is used in the production of structures that will function in such environment.

6XXX: Al-Mg-Si Alloys: The main alloy elements are magnesium and silicon. These alloys that can easily be shaped are used especially in the production of the parts manufactured by means of extrusion.

7XXX: Al-Zn Alloys: Copper is the main alloy element, whereas magnesium, chrome and zirconium are the additional alloy elements. 7XXX series is the aluminium alloy which has the highest resistance. It is used in manufacturing aircraft parts and in other areas where high resistance is required.

8XXX: Al-Li Alloys: The basic alloy element is lithium and can also be added with some tin. This material, especially used in aircraft and aerospace structures, has a high fatigue resistance and high toughness properties. But, the production costs are high compared to other Al alloys.