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

HomeFAQsBooksHelpWantedAdvertiseForum
(current
topics)
topic 11599

White spots on anodised surfaces


 

We are making H2SO4 anodising in our plant. Although we are able to keep constant temperature of 21 °C, we are facing problems after anodising.

1-) Sometimes we see tiny white spots on the profiles which are permanent.
2-) What is the necessity of air agitation in the tank. We don't have agitation at the moment.
3-) What happens if we don't reach the necessary temperature at hot sealing.

Serdar Yolcu
- Balikesir, Turkey


 

I think the white spots are atmospheric corrosion developed on the aluminium between extrusion and anodizing processes.

Air agitation is very important not to have hot areas during anodizing which results in softer anodic film and variations in film thickness.

If you do not reach the sealing temperature, the anodic film is not sealed properly. The anodic film is prone to chemical and physical attack during service. It holds dirt and loses decorative appearance with time.

QUALANOD specifications tell you what the conditions of anodizing process must be to have a good quality in anodizing.

Timur Ulucak
aluminum extrusions & finishing - Istanbul, Turkey



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

ADD a Q or A to THIS thread START a NEW THREADView CURRENT TOPICS

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


©1995-2017 finishing.com     -    Privacy Policy
How Google uses data when you visit this site.