×
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

Super-Cooled Flint

Super-Cooled Flint

Super-Cooled Flint

(OP)
I was wondering if anyone could tell me why flint becomes magnetic when you freeze it with liquid nitrogen? I was playing around the other night freezing whatever material I could find laying around just for fun when the piece of flint was sucked right out of the dish and stuck to the magnet I had. I was pretty sure it wasn't naturally magnetic but just to make sure I grabbed another piece I had and checked. The magnet had no effect on that piece, but the frozen one sure was magnetic. It slowly lost its attraction to the magnet as it warmed back up and was back to being non-magnetic somewhere close to 0 degrees C. I repeated everything several more times just to make sure I wasn't crazy. So what's going on? I know superconductors will make a magnet float above it, but I haven't ever heard or read about making material magnetic by freezing it. Are there any similarities between these two phenomena?

RE: Super-Cooled Flint

Some components within the flint have Curie temperature between room temperature and -200 deg C.  Not sure which.  Below these temperatures material becomes Ferromagnetic and strongly attracted to magnet.

RE: Super-Cooled Flint

most flint is ferromagnetic at room temperature or marginally so depending on the grade and temperature

 

RE: Super-Cooled Flint

There are metals that do this also, simply depends on the curie temp.

This effect has industrial uses and some alloys exist with tightly controlled curie temps.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: Super-Cooled Flint

believe the material referred by the OP is classified as an intermetallic

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