×
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!

*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

Chromate or Phosphate??

Chromate or Phosphate??

Chromate or Phosphate??

(OP)
i'm looking at specifying a conversion coating on some mild steel vessels.  currently, our supplier is using an iron phosphate as the 'primer' then is powdercoating the exterior, a common practice.  the corrosion resistance is insufficient though, because after storing or operating these vessels, the interior of the vessels rusts.

i've noted that zinc phosphate is a slightly more expensive, yet more durable and effective coating than the iron phosphate currently used, but is unavailable in my area.  zinc chromate is readily available though and i was wondering if the corrosion resistance is better or worse?

RE: Chromate or Phosphate??

"Zinc chromate" will be much better than either iron phosphate or zinc phosphate for corrosion resistance if you consider these coatings alone, but it may not promote adhesion of other materials like the phosphate treatments do, which may result in worse performance.  You must work on the entire system - talk to the powder coating supplier about acceptable primers.

RE: Chromate or Phosphate??

(OP)
can you zinc chromate mild steel?

our local shops have only really done it on aluminum.

RE: Chromate or Phosphate??

Mild steel is easy to plate with zinc plus chormate conversion coatings.

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


Resources

Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now
The Great Project Profitability Debate
A/E firms have a great opportunity to lead the world into the future, but the industry’s greatest asset—real-time data—is sitting wasted in clunky, archaic ERP platforms. Learn how real-time, fully interactive dashboards in a modern ERP allow you to unlock data that will shape the future of the world. Download Now

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