45095

Iron Contamination of sulfuric acid anodizing solution  

+++++++

We are a distributor of galvanic processes and one of our customers has a problem with the anodizing. The parts to anodize are aluminium made but have a little area made from iron. This iron area of the part can't be separated (thay are manufacturated that way).
Now, the problem is that the sulfuric acid anodizing solution is trapping iron from that area and now is full of it. This iron inhibits the action of the anodizing solution so the effect on the part is not uniform, homogenous.
So the question is, anyone knows about how to remove this iron from the anodizing solution?
Thanks in advance.

Gorka Bilbao
Distributor - Arrankudiaga, Bizkaia, Spain

First, it is necessary to mask over the iron prior to anodizing.

You probably can remove much of the iron from the solution by electroplating onto an auxiliary cathode. For this 'dummy plating,' use the anodizing cathodes as anodes, and hang the auxiliary cathode from the anodize workbar. Start with 6 Volts and adjust if needed.

Ken Vlach - Goleta, California

Thank you so much. I'll tell my customer to do so.
Thanks again.

Gorka Bilbao
- Arrankudiaga, Bizkaia - Spain

We are a distributor of aluminium anodizing processes. One of our customers has a problem with the anodizing. The problem is that the sulfuric acid anodizing solution reaches 250 ppm of iron. This iron inhibits the action of the anodizing solution so the effect on the part is not uniform.

Mr. Ken Vlach (in letter from +++++++ ) advises that we can remove much of the iron from the solution by dummy plating onto an auxiliary cathode by using the anodizing cathodes as anodes. In the process we have lead made cathodes.

My question is:
Can we make dummy plating with lead anodes and aluminium cathodes.
What is a range of the Voltage we need
What is surface ratio we need for dummy plating?
Thanks in advance.

Teddy Braude
Q.A. manager - Akko, Israel