Difference Between Aluminum and Stainless Steel

Aluminum vs Stainless Steel
 

Steel is an alloy made out of iron and carbon. The carbon percentage can vary depending on the grade and mostly it is between 0.2% and 2.1% by weight. Though carbon is the main alloying material for iron some other elements like Tungsten, chromium, manganese can also be used for the purpose. Different types and amounts of alloying element used determine the hardness, ductility and tensile strength of steel. Alloying element is responsible for maintaining the crystal lattice structure of steel by preventing dislocation of iron atoms. Thus, it acts as the hardening agent in steel. The density of steel varies between 7,750 and 8,050 kg/m³ and, this is affected by the alloying constituents too. Heat treatment is a process which changes the mechanical properties of steels. This will affect the ductility, hardness and electrical and thermal properties of steel. There are different types of steel as carbon steel, mild steel, stainless steel, etc. Steel is mainly used for construction purposes. Buildings, stadiums, railway tracks, bridges are few places among many where steel is heavily used. Other than that, they are used in vehicles, ships, planes, machines, etc. Most of the daily used house appliances are also made by steel. Now most furniture is also replaced by steel products.

Aluminum

Aluminum or Al is an element in the group 3 and period 3 which has the atomic number of 13. The electron configuration of Al is 1s² 2s² 2p⁶ 3s² 3p¹. Al is a silvery white solid, and it is the most abundant metal in the earth crust. Al is not soluble in water at room temperature. Atomic weight of Al is about 27 g mol^-1,and it is a light weighted, low density and durable metal. It is a good electric conductor.  Al doesn’t easily ignite. Al is showing both metallic and non-metallic characteristics; hence, it is amphoteric. As a metal, it reacts with acids releasing hydrogen gas and forms the +3 charged metal ions. As a non-metal, it reacts with hot alkali solutions and form aluminate ions.

Since Al is too reactive to stay in its free form, naturally it occurs in minerals. Main Al containing mineral is bauxite. Large bauxite ores are located in Australia, Brazil, Jamaica and Guinea.  It is also in the minerals such as cryolite, beryl, garnet, etc. Al is largely used in automobiles and other vehicles manufacturing, construction, paints, for household items, packaging etc. due to its low density and resistance to corrosion. Pure aluminum is soft and lack in strength to use it, but it is mixed with other elements like iron or silicon (in small amounts) to increase the strength and hardness.

Stainless steel

Stainless steel is different from other steel alloys because it doesn’t corrode or rust. Other than this, it has other basic properties of steel as above mentioned. Stainless steel is different from carbon steel due to the amount of chromium present. It contains minimum 10.5% to 11% chromium amount by mass. So it forms a chromium oxide layer which is inert. This is the reason for non-corrosion ability of stainless steel. Therefore, stainless steel is used for many purposes like in buildings, monuments, automobile, machinery, etc.