The key difference between alloy and aluminum is that an alloy is a substance formed from mixing two or more different chemical elements whereas aluminum is a chemical element that we can find on earth’s crust as a metal.
Aluminum is a metallic element with a silvery white appearance that is found in abundance in earth’s crust. Though making up almost 8% of the earth’s crust, it does not occur naturally as a free metal as it is chemically too reactive. On the other hand, an alloy is a substance that is consisting of several chemical elements. Aluminum has a wide range of applications in producing alloys because when we are converting metal into an alloy, it enhances the properties of the metal. Therefore, it becomes more useful to use the alloy rather than the individual metal.
CONTENTS
1. Overview and Key Difference
2. What is Alloy
3. What is Aluminum
4. Side by Side Comparison – Alloy vs Aluminum in Tabular Form
5. Summary
What is Alloy?
An alloy is a substance in which we combine several chemical elements to enhance the properties of a metal. For the production of an alloy, we can combine either two or more metals or a metal and another chemical element. Either way, it forms an impure substance because there are several components in an alloy. We call it an “admixture”. It retains and enhances the characteristics of a metal. However, it is not an impure metal, because we produce an alloy by adding components under controlled conditions and in defined amounts that provide desirable properties. Specifically, one or more component in the alloy must be a metal.
Figure 01: Bronze is an Alloy
The most common and the oldest technique of producing an alloy is by heating the metal beyond its melting point to dissolve the other components into the molten liquid. This is possible even if the melting point of the solutes are far greater than this temperature. However, this technique is not useful with metals and elements having very high melting points; eg. Iron and carbon. There, we should use the technique of solid state diffusion in order to make the alloy. Or else, we can use a method that has all the components involves in the alloying process in their gaseous state.
Types
There are two major types of alloys that can form during the alloy production namely, substitutional alloys and interstitial alloys. These two forms differ from each other according to the mechanism from which the alloy forms. Substitutional alloys form via atom exchange mechanism while interstitial alloys form via the interstitial mechanism. In brief, the atom exchange mechanism occurs when the atoms of the constituents are relatively similar in size whereas, an interstitial mechanism occurs when one type of atoms is much smaller than the other type of atoms.
What is Aluminum?
Aluminum is a chemical element having the atomic number 13 and chemical symbol Al. It appears as a silvery-white, soft metal. Moroever, it is nonmagnetic and highly ductile. It is abundant on earth (8% of earth’s crust). This metal is highly chemically reactive. Therefore, it is difficult to find native specimens of aluminum. Especially, this metal has a low density. Thus, is lightweight and it is able to resist corrosion via forming an oxide layer on its surface.
Some chemical facts about this metal are as follows:
- Chemical symbol is Al.
- Atomic number is 13.
- Electron configuration is [Ne] 3s2 3p1
- Standard atomic weight is 26.98.
- At room temperature and pressure, it is in a solid
- The melting point is 660.32 °C
- The boiling point is 2470 °C
- Most stable oxidation state is +3.
Figure 02: Aluminum Metal
When considering the alloys of aluminum, the typical alloying components are copper, magnesium, zinc, silicon and tin. There are two forms of aluminum alloys as casting alloys and wrought alloys. We can divide both these groups into two groups as heat-treatable and non-heat-treatable aluminum alloys. However, about 85% of the useful aluminum alloys are wrought forms.
What is the Difference Between Alloy and Aluminum?
Aluminum is a chemical element while an alloy is a mixture of several chemical elements. Hence, the key difference between alloy and aluminum is that an alloy is a substance formed from mixing two or more different chemical elements whereas aluminum is a chemical element that we can find on earth’s crust as a metal. In its pure form, aluminum has no use because of its low tensile strength but finds extensive use when its alloys are made by adding elements such as zinc, manganese, copper, and magnesium.
Summary – Alloy vs Aluminum
Aluminum is a metal that we can find on earth’s crust in abundance. On the other hand, an alloy is a substance that forms from mixing two or more different elements. The key difference between alloy and aluminum is that an alloy is a substance formed from mixing two or more different chemical elements whereas aluminum is a chemical element that we can find on earth’s crust as a metal.
Reference:
1. “Aluminium.” Wikipedia, Wikimedia Foundation, 18 Oct. 2018. Available here
2. “Alloy.” Wikipedia, Wikimedia Foundation, 27 Sept. 2018. Available here
Image Courtesy:
1.”Türzieher Bremen 1405″By Alfred Löhr – Own work (Public Domain) via Commons Wikimedia
2.”Aluminium-4″By Unknown (CC BY 3.0) via Commons Wikimedia