finishing.com -- The Home Page of the Finishing Industry

HomeFAQsSuggested
Books
Help
Wanteds
Advertise
on this site
FORUM
current topics
Live! From beautiful Pine Beach New Jersey: Welcome to the world's most popular metal finishing website

topic 32184

E-Coating of Magnesium Castings

adv.   coatec india banner

2004

I currently have a customer that has requested E-Coating of the Magnesium Castings we supply. We have attempted to have the components plated using our customers Plater and have not had good success. The problem we are experiencing is that the E-Coat bubbles during their testing (90% humidity testing - no salt spray). They currently clean the castings with a sulphuric acid rinse and then zinc phosphate prior to e-coat. Is this method of plating incorrect? Can you suggest an alternative method to have the castings E- coated? Any help would be appreciated.

Perry Longhurst
FisherCast Global - Zinc & Mag castings - Peterborough, Ontario, Canada

2004

The e-coat is likely bubbling due to the porosity that is present in the casting. The sulfuric acid etching process will remove ~ 50 micrometers from the surface, which may result in exposed porosity. However, you should investigate the exact process used by the e-coat supplier. Is the sulfuric acid rinse in-line with the rest of the coating process, or is it completely separate? The Mg surface needs to be etched prior to zinc phosphate, which can be done using either an alkaline etch (pyrophosphate alkaline cleaner) or acid pickling. I am not sure if all of the phosphate conditioners used for processing steel are appropriate for Mg. The pre-treatment supplier should be consulted on this.

Toby Padfield
Automotive module supplier - Michigan



If you have a question in mind which seems off topic, please Search the Site

ADD a Q, A, or Comment on THIS topic START an UNRELATED topicView CURRENT HOT 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


©1995-2019 finishing.com, Inc., Pine Beach, NJ   -   About finishing.com   -  Privacy Policy
How Google uses data when you visit this site.