×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Graphite as a corrosion inhibitor

Graphite as a corrosion inhibitor

Graphite as a corrosion inhibitor

(OP)
Has anyone ever heard of adding a small quantity of graphite to an automotive cooling system to inhibit corrosion?
I've found the attached link, but can find no other references to the practice anywhere.
Does it make sense that a light deposit on the various metals in the engine block might neutralize the electrical potential between them?

http://www.malibuwater.com/graphite.html

RE: Graphite as a corrosion inhibitor

there is a type of corrosion called "graphitizing" - where cast iron parts loose some of their C contained in the metal structure and then become brittle. In those circumstances it is thought that a suitable coating might retard the proces - perhaps a certain amount of graphite (C!) might prevent the graphite contained in the cast iron dissolving in the surrounding coolant.

in the past graphitizing of cilinders was rather common in larger bore engines, but now it seems to occur very seldom, perhaps due to improved materials and/or casting techniques.

i must say i have come across this phenomenon in big engines in the past 30 years ago, but never saw it in automotive engines.

coating of coolant parts has been used though for other purposes like preventing caviation erosion.  a small amount of emulsifiable oil in the coolant would be able to stop or retard the process - but here also due to better coolants and metals the probelems seem to have disappered nowadays.

RE: Graphite as a corrosion inhibitor

Whoa.... I've never seen graphitization being described as corrosion.... From what I know its due to the movement of carbon atoms at higher temperatures in steels.

In grey cast iron the carbon primarily forms as interconnected 3D flake shapes, this carbon is exposed on all cut surfaces and is the primary reason for the use of this material.

I dont see how graphite will prevent corrosion in modern engines. In fact if IIRC graphite and Aluminium form a great (horrible) corrosion couple.

Nick

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources