Authoritative Answers, Fun, & Aloha -- no cost, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Home /
Site 🔍
pub     mobile?
Metal finishing Q&As since 1989


Hypophosphite - What's it for and what does it do?



I work for a shop that does electroless nickel plating, and I would like to know about sodium hypophosphite. What significance to the electroless nickel bath does this chemical play.

If it goes above the recommended concentration, will it damage the bath?

What is it used for in the bath? Does it normally increase as the bath is used?

I've just begun titrating it weekly, which we never did before. It shows an increase of approx. .5 each week. Before, we only titrated it at the make-up of a new bath.

Please help me, I'm not that knowledgeable, just a lab tech, and could really use someone with real time knowledge on this subject.

Thank You,

Kathi Houchin
- Anaheim, California, USA

It is NaH2PO2.H2O and has a molecular weight of 106. It is a reducing agent and used to reduce nickel ions to nickel metal in some electroless nickel baths.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

Sodium hypophosphite is the chemical that causes nickel to deposit. With out it no plating can take place. It is not harmful if there is more than the recommended amount as far as the plating is concerned. It may increase the deposit rate slightly. Continued use of concentrations above the recommended amount can lead to somewhat shorter solution life, since sodium hypophosphite is oxidezed to the orthophosphite form by heat and by reducinging nickel ions. The orthophosphite form is less soluble and when it reches a high level, precipitation can occur causing plat-out or spontaineous decomposition of the plating solution, plating out nickel powder. If you have additional qluestions, e-mail them to me. I suggest you take the AESF electroless nickel Plating course. Or if your company will allow I or others can put on a course for you and other employees of your company. Ask for costs.

don baudrand
Don Baudrand
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [on Amazon or AbeBooks affil links]
           and "Plating ABS Plastics" [on Amazon or eBay or AbeBooks affil links])

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully 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 might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

Chemicals &
& Software

About/Contact  -  Privacy Policy  -  ©1995-2024, Pine Beach, New Jersey, USA  -  about "affil links"