Anodic Coatings per MIL-A-8625 Type II and Type III

[pylfrm]

Hello folks,

I am looking for some answers to a series questions, possibly rather unusual, about anodizing aluminum. Any insight will be appreciated.


Is it possible for a coating in accordance with MIL-A-8625 Type III to also meet the requirements of MIL-A-8625 Type II Class 2?

If not, which specific requirements of MIL-A-8625 preclude this?

If so, how practical is this?


To give a bit of background: I am a customer of anodizers, not an anodizer myself. The Type II Class 2 compliance is a contractual obligation. The Type III coatings provide some internally desirable characteristics, most importantly better control of surface growth and total thickness tolerances.

Thanks for taking a look,

pylfrm

 

[tbuelna]

The short answer to your first question is no.

In response to your second question, I'd suggest you start with section 4 of MIL-A-8625 that covers QA compliance.

 

[pylfrm]

tbuelna,

Thanks for your response. I've read through section 4, and the two types clearly have different test requirements. However, I didn't find any outright conflicts, so perhaps it would be possible with additional testing?


pylfrm

 

[tbuelna]

pylfrm-

You might want to take another look at section 4.3.1 where it talks about the Process Control Document every vendor must develop, maintain and follow for each specific process in the spec that they intend to perform. I think you would need a separate PCD for type II and type III, due to the differences in each process.

 

[pylfrm]

tbuelna,

You have a point there. Looks like a good bit of work (both testing and process control documentation) might be required before attempting this.

Thanks.

pylfrm