-- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing

on this site
current topics
topic 061

Passivating an electroless nickel tank

A discussion started in 1995.
Add your Q. or A. to restore it to the "Current Topics" discussions.


Hello,   I'm in charge of electroless nickel/immersion gold line in a PCB shop. I've some problem with Ni plate-out after running the bath for few days. We are using stainless steel tank with a sump tank for heating up & circulating the bath. We also install some sort of anodic protection for the tank. My questions are:  

1) How to minimize or prolong the onset of the plate-out?

2) What is the best way to leach & passivate the tank? With nitric acid, what should be the desirable strength & at what temperature. What about the rinsing after the leach?  

Well appreciate your advise & help. Thanks.   Regards,

Bab Hui
Process Engineer 

The purpose of the anodic protection unit is to prevent plate-out onto the tank, and it should have detailed instructions for how to set the current to do so.

Such units are, I believe, available from Atotech and Palm International.

The usual idea behind leaching is to expose the tank material to a solution which has the same capability for absorbing contaminants as the working solution will have, but for the leaching solution to not introduce any new contaminants to the working solution. So room temp or slightly warmer nitric acid sounds good to me--but why not just go ahead and follow a QQ-P-35 [link is to free spec at Defense Logistics Agency,] nitric acid passivation procedure on the tank itself.

Ted Mooney, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey

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


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.