-- The Home Page of the Finishing Industry
23+ years of serious education, promoting Aloha,
& the most fun you can have in metal finishing smiley
    no popups, no spam
on this site
current topics
topic 5129

Possible Chemical Reactions Between Objects With Differently Plated Surfaces


A frequently asked question by our customers in the fastener industry is,"If I use a certain plating on one object and it is in constant contact with another,different plating(such as two threads),will there be any reactions such as binding?".Is there a chart that one can consult?.

Robert John Evans
- Sydney,New South Wales,Australia.


The most common cause for corrosion is the contact of two dissimilar metals, so, in a word, yes, there will be reactions occurring. To get to specifics, consult a galvanic series chart.

James Totter
James Totter, CEF
- Tallahassee, Florida


Hello Robert ,

If you mean two different metallic coatings, then a chemical reaction is unlikely, if one of the coatings is something else you'll need to be more specific. However if the environment is corrosive - and most are to some degree, then the most anodic metal/alloy will corrode to protect the more cathodic - even if this is simply one that it is in contact with. Hope I didn't just tell you what you already know. Ian

Ian Brooke
university - Glasgow, Scotland


Dear Mr. Evans:

The best rule of thumb would be to use the same plating on both mating surfaces. I would not consider "binding," to be a reaction, but rather a physical characteristic of the plated coating(s). Speaking of the sacrificial coatings,for example, a threaded surface plated with Cadmium mated to a part plated with zinc or zinc alloys will form a galvanic couple and corrode quite rapidly.

Therefore, if you are in the business of refurbishing parts for your industry and receive Cadmium plated parts, please do not plate the mated part with zinc or zinc alloys without first stripping the cadmium off of the part and replating with zinc or Zinc Alloy.

Any problems left with the lubricity of the screw threads can be cured with proprietary products used for lowering the coefficient of friction on the plated surface. These can usually be applied by a dip, spray, or brush on method. Contact your plating supplier to see if he/she has a product to suggest to you. Sincerely, Ed Budman

ed budman
eb sig
Ed Budman
- Pennsylvania


As in the previous responses, binding from galvanic corrosion is probably your concern. The Galvanic Series, which can be found in most corrosion books, is the chart the will help you to determine whether the specific metals combination is likely to be a problem.

larry hanke
Larry Hanke
Minneapolis, Minnesota

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Comment to THIS thread START a NEW threadView CURRENT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2018, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.