ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Types Of Corrosion

Updated on October 22, 2011

Corrosion is a phenomenon in which the surface of a metal is destroyed due to certain external factors which thin it down, make it lose its strength and luster, and make it fragile. Corrosion is a very common phenomenon amongst metals. Various factors work on the surface of different metals at various rates.

Corrosion strongly depends on the resistance of a metal towards it, like some metals such as gold and platinum are strong and resistant towards corrosion whereas iron is very vulnerable as it quickly corrodes on being exposed to moisture and excess oxygen.

When it comes to dividing corrosion into different types, there are various bases for its classification. If we want to classify corrosion based on their characteristics and mechanisms there are eight types of corrosion. Based on their Ionic or Electro-chemical theory there are three types of corrosion: Auto corrosion, Contact corrosion and Externally induced corrosion. Focusing on the former criteria, below given are the eight types of corrosion:

Uniform Attack

In the uniform attack the corrosive agent working on the surface of the metal reacts with the surface ions uniformly over the surface of the exposed metal making the metal thin and fragile.

After some time the metal completely loses its strength.

The uniform attack is the most common type of corrosion an example of which is the rusting of iron when exposed to moisture.

Metal erosion caused by winds near seashore.
Metal erosion caused by winds near seashore.
Pitting Corrosion
Pitting Corrosion

Selective Leaching

Selective leaching takes place in metal alloys. In selective leaching one of the metals on the alloy undergoes corrosion.

Selective leaching may be done intentionally to remove one metal from the alloy.

The most common example of selective leaching is the removal of zinc from brass also known as dezincification.


Erosion is yet another common type of corrosion which occurs naturally. In corrosion the surface of the metal slowly and gradually deteriorates by the action of the environment.

Eventually due to the constant attack of the corrosive agent on the metals, the surface of the metals wears away forming holes and gullies on the surface.

The pits formed are mostly directional and have a pattern.


Pitting is perhaps the most dangerous and vicious of all the other types of corrosion. In pitting small or large and deep or shallow pits and holes are formed on the surface, completely destroying the metal.

If pitting occurs in a metal machine the machine completely stops working. It is caused due to some chemical corrosive reagents.

Another reason why this form of corrosion is considered the most dangerous is that this type is difficult to predict and although it may take place gradually and silently the function of the metal stops suddenly without a warning.

Microscopic view of a metal affected by Intergranular Corrosion
Microscopic view of a metal affected by Intergranular Corrosion
Stress Corrosion Cracking of a fuel pipe
Stress Corrosion Cracking of a fuel pipe

Intergranular Corrosion

The grain boundaries of some metals are very reactive.

Because of these active grain boundaries, when there is a corrosive attack on the metal the grains of the boundaries start to react with the agent, this causes Intergranular corrosion.

The Intergranular corrosion mostly occurs in alloys and may be at times due to some impurities present on the grain boundaries.

Stress Corrosion Cracking

The stress corrosion cracking is a unique type of corrosion in which cracks are formed on the surface of the metal due to a specific agent causing stress on the surface and eventually breaking the metal down.

The two common examples of stress corrosion cracking are: season cracking of brass, and the caustic embrittlement of steel.

During the process of corrosion, the rest of the surface remains intact while small and fines cracks proceed at one point.

These cracks then extend further breaking through the surface of the metal.

This type of corrosion is not very common and occurs only when the metal is exposed to a specific medium.

Galvanic Corrosion caused due to difference in anodic index of plates and bolts
Galvanic Corrosion caused due to difference in anodic index of plates and bolts
Silver Bridge collapse caused due to Crevice Corrosion in 1967
Silver Bridge collapse caused due to Crevice Corrosion in 1967

Galvanic Corrosion or Two-Metal Corrosion

In galvanic corrosion a less resistant metal and a high resistant metal are placed together in a corrosive medium.

Due to the potential difference between the two metals there is an electric flow between metals, this makes less resistant more vulnerable and the high resistant more strong.

This is called galvanic corrosion.

Crevice Corrosion

Crevice corrosion is an intense localized corrosion which occurs within crevices and other shielded areas on metal surfaces when it is exposed to corrosive agents.

This results in holes and puts on the surface of the metal.


    0 of 8192 characters used
    Post Comment

    • jbosh1972 profile image


      6 years ago from Indianapolis, IN. USA

      I appreciate the systematic break down of the different corrosion types. Perhaps you should right hubs going into detail of how the different kinds of corrosion can occur. Also, check out my hubs. My interest are welding, art, chemistry, and metallurgy.

    • agusfanani profile image


      7 years ago from Indonesia

      This hub has given me something I've never known before. Thank you.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)