Main Difference – Chrome vs Stainless Steel
Chrome and Stainless Steel are heavily used in industry, especially in construction and utility products. Chrome is a shortened form of the Chromium metal. Stainless steel is an alloy, which means it is made up of several elements. As the name suggests, it is a type of material that doesn’t corrode. The main difference between Chrome and stainless steel is that Chromium has a higher oxidation potential whereas stainless steel is protected from oxidation.
What is Chrome
As mentioned above, Chrome refers to the chemical element Chromium, which is the 24th by atomic number in the periodic table belonging to the Group 6 elements – the d block. It is symbolized by ‘Cr’ and as it is a d block element, it has the property of existing in different oxidation states. The most common oxidation states in which it is found are +3 and +6. Chromium is a lustrous and brittle metal and is greyish in colour.
Chromium metal has been discovered in rare minerals. However, nearly all the Chromium used for commercial purposes are derived from Chromite, which is an Iron-Chromium Oxide. Chromium is commonly used as a sacrificing metal to prevent another metal from oxidation. This is mainly seen in the case of steel which needs to be protected from rusting upon the exposure to air and moisture. This is achieved through a process called chrome plating, where the liquidized form of Chromium is applied on the other metal of interest, to prevent it from oxidizing. The logic behind this is that Chromium could protect any other metal which has a lower oxidation potential compared to Chromium. In the famous example of the metal Iron in steel, Iron has a lower oxidation potential in the presence of Chromium, which makes Chromium more susceptible for wearing off, whereas the Iron stays protected.
What is Stainless Steel
Stainless Steel is the form of steel that does not corrode when exposed to air and moisture. This is not susceptible to oxidation. It is an alloy which is mainly made of Iron, and other elements such as Carbon and Chromium. In general, the Chromium content should not be less than 10.5%. Stainless steel differs from Carbon steel due to the amount of Chromium present. Carbon steel gets rusted rapidly when exposed to air and moisture. Iron, when exposed to air, forms Iron oxides which settle as a layer of rust which accelerates corrosion, forming more iron oxide.
However, due to the presence of Chromium, the iron in the steel is protected from oxidation. As mentioned above, in the case of exposure to air and moisture, it is Chromium that gets oxidized first. Stainless steel comes in different grades depending on the quality and the finishing of the steel, and its uses are determined accordingly. Stainless steel is often used when both the strength of the steel, as well as resistance to corrosion, is required.
Difference Between Chrome and Stainless Steel
Definition
Chromium is a metal in elemental form.
Stainless Steel is an alloy made up several elements; mainly Iron, Carbon and Chromium.
Oxidation States
Chromium being a d block element exists in various oxidation states.
Stainless Steel doesn’t have oxidation states as such, as it is an alloy.
Oxidation Potential
Chromium has a higher oxidation potential when compared to Iron.
Stainless Steel is protected from oxidation due to the presence of the layer of Chromium.
Usage
Chromium is commonly used in Chrome plating and also in the production of alloys.
Stainless Steel is mainly used for construction purposes and to produce utility products.
Image Courtesy:
“Haresh Steel Centre – Stainless Steel Sheet Plate Strip Coil Circle” By Jatinsanghvi – Own work, (CC BY-SA 3.0) via Commons Wikimedia
“Decorative chrome plating on a motorcycle”By Atoma – Own work, (CC BY 2.5) via Commons Wikimedia