No registration, no passwords; no pop-up ads -- just aloha, fun, & authoritative answers.
As an eBay Partner & Amazon Affiliate we receive compensation for qualifying purchases.
Home /
Search 🔍
the Site
pub  Where the world gathers for
plating, anodizing, & finishing Q&As since 1989


Patchy / stained Nickel chrome deposit


We do duplex nickel chrome plating of automobile wheel rims in an automatic plating plant using horizontal rack loading using both cylindrical central anode basket within the rack and external anode baskets. Anode baskets are titanium filled with nickel squares. The nickel plating is traditional Watts bath and the chrome is conventional Chromic acid/sulfuric acid.We have been facing a peculiar type of defect. This appears in the form of bluish white patchy/stained deposit. We have tried the following without much success :

1. Activating chrome dip before Chrome plating
2. Discard of Nickel Drag out more frequently
3. Improved rinse flow after nickel
4. Minimize transfer time from Semi-bright to Bright
5. Addition of Sodium lauryl sulphate to Bright Nickel

The brightener supplier has given us a proprietary salt which he calls Nickel Sequestrant. Addition of this gives relief albeit temporarily. The problem reappears after a couple of days. Can someone suggest what I need to do ?

Vijay Rao
an electronics company - Bangalore, India

You really didn't specify whether you saw this in the Nickel or only after Chrome plating. If the Nickel looks fine then a close look at the Chrome is necessary. Temperature imbalances can cause this.

There is also a common problem called whitewash. This usually occurs with older solutions with high levels of metallic contamination. These trace metals seem to plate out in the lower current densities causing a haze. My troubleshooting rule of thumb has always been to work my way back from the process where the defects first become obvious.

jim conner
Jim Conner
Anoplex Software
supporting advertiser
Mabank, Texas USA
Anoplex logo

(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 &
Consult'g, Train'g
& Software

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