×
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

High temperature service performance of sacrificial anodes

High temperature service performance of sacrificial anodes

High temperature service performance of sacrificial anodes

(OP)
I am looking for any information (e.g. life expectancy, measured potentials) about operating sacrificial anodes (galvalum I, galvalum III, Magnesium H-1 Alloy) at elevated temperatures - up to 200C (392F). Any experience/information/references especially with galvalum III over 100C (212F) would be helpful.  

RE: High temperature service performance of sacrificial anodes

Come back with more details of the enviroment and conditions that you are considering.

Just remember that for an anode to work it has to dissolve form metallic salts that have to go somewhere.

RE: High temperature service performance of sacrificial anodes

(OP)
We are protecting internally coated tanks which will contain an oilfield produced water phase. Resistivities averaging 100 ohm-cm, but vary from 10 ohm-cm to 500ohm-cm.  Do you have any experience at these temperatures?  

RE: High temperature service performance of sacrificial anodes

I just check this morning and the highest temperature we have used Galvalum III is 65°C.  

We did test some higher temperature services using different type anodes.  Presently I don't have access to the results  information.  My recollection is that we experienced some very high anode dissolution rates.   

I would check with CPT or Corrpro


www.cpt.net

www.corrpro.com

RE: High temperature service performance of sacrificial anodes

(OP)
I've tried Corrpro. They sent me a brochure on Galvalum, which has data up to about 100 C.  I know dissolution will be higher, but I'm trying to quantify/approximate how much higher. I know that resistivy goes down with temperature, which may confuse some people into thinking some other mechanisms are involved.  Results seem to flatline for performance above that temperature.  This makes sense because I've read the corrosion reaction actually decreases slightly above 90 or 100.

Anybody else have any data?  

RE: High temperature service performance of sacrificial anodes

I have had experience using sacrifical Galvalum anodes up to about 325 F in similar applications.  One of the principal problems initially encountered was rapid wastage of the anode and subsequent cathodic disbondment of the internal coating and corrosion of the carbon steel base metal.  Initial solution involved limiting the surface area of the anode exposed to the environment by encapsulating nearly 90% of the anode surface. Even so, some disbondment of coating immediately adjacent to the anode attachment location occurred.  Type 316L stainless steel cladding was eventually selected for equipment exposed to similar environments.       

RE: High temperature service performance of sacrificial anodes

I've seen a comment somewhere (long ago) that zinc anodes become cathodic to steel above some temp.  The temp wasn't all that high--IIRC it was a home hot water heater.

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