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!

*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

Identification of hard grey coating on aluminium strip

Identification of hard grey coating on aluminium strip

Identification of hard grey coating on aluminium strip

I have a sample of aluminium (6061-T6) that has a hard, highly adherent matt grey coating on both surfaces. I need some method of identifying the coating type. Any ideas?
What I know so far is
-The coating remains intact/adherent during a tensile test
-coating is harder than the aluminium substrate
-coating does not contain fluorine (ie no PTFE or similar)
-no primer visible microscopically on polished cross section
-thickness of 30-35 microns
Replies continue below

Recommended for you

RE: Identification of hard grey coating on aluminium strip

Is it a good electrical insulator?
How much extension did you do in tension?

There's a good probability that it's hard anodize (anodic oxide). I would expect some cracking from tensile or bend tests, though.  See a brief description of anodic coatings for Al 6061 & other alloys at

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! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close