Aloha, fun & authoritative answers -- no cost, no registration, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Adver-
tise
Help
Wanted
Current
Q&A's
Site 🔍
Search
pub  Where the
world gathers for metal finishing
Q&As since 1989



-----

Reoxidizing trivalent chrome to hexavalent




We are experiencing difficulty in lowering trivalent levels in our Chrome bath.
Using dummy load 4:1 anode to cathode ratio,six volts. Is there possibly some other Ions that could be stopping the reoxidation from proceeding?

William Bonty
Captive Plating Shop - Grand Rapids, Michigan
2006



First of two simultaneous responses --

Try a ratio of 10 to 1. You are trying to generate oxygen, not plate. I would strongly consider using porous pot technology. Hard Chrome Consultants in Cleveland, OH used to have a good lower priced unit. This removes most tramp cations at converts the trivalent to hex.

James Watts
- Navarre, Florida
2006



Second of two simultaneous responses --

You're on the right track, but try anode/cathode more like 100:1.

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg, South Carolina
2006



2006

Agree with Jeffrey, the most important is you have to make sure that your anode is clean without heavy yellow film that can protect the current to flow and stop re-oxidation reaction.

My suggestion you should put the anode with current during dummying or electrolyzing to prevent the formation of the yellow heavy film.

Good luck,

Tony Chandra
- Jakarta, Indonesia



I WOULD SUGGEST YOU TO FIRST ANALYSE YOUR BATH IN ANY LAB AND CHECK FOR TRIVALENT , COPPER ,IRON ETC . IN A. A .S
THEN A REMEDY CAN BE SUGGESTED.
WITH REGARDS,

ajay raina
Ajay Raina
Ludhiana, Punjab, India
2006




(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:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


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