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

Where the
world gathers for metal finishing
Q&As since 1989

-----

Anodized aluminum has microscopic black dots on its surface

August 30, 2021

Q. Hi, I am a student studying aluminum anodizing.

I've got a question about my anodizing.
My anodizing condition is 15V 25°C 25-45 min anodizing on AL1050 (sulfuric acid 2M).

I don't know the reason but when I look under a microscope(450x) it seems uneven (not a clean white or grey). It has grey background and black dots on it.
(The dots are invisible to the naked eye. It can only be observed through a microscope with a magnification of 3000 or less.)

61317-1

This has always been there and I don't think it's a problem, but I'd like to know what these black dots are and how to get rid of them.

yoonhee kim
- si-heung Gyeonggi-do

(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: