Electroless nickel plating - surface preparation

[AligatorAmy]

Hi,

I am conducting the experiments with the electroless nickel plating of the brass (CZ121).
I have read a lot of the literature about this process prior to the lab tests.

All brass surface cleaning procedures that I have came across involve the electro cleaning (I understand why). However, I wonder whether some recepture could be recommended for CZ121 brass which does not involve electro cleaning. My main target is not the excellent quality of the Ni-P plating but to get the process working with simplified cleaning to proof the specific concepts (rapid prototyping).
P.S. The regular Ni-P coating providers cannot ensure their service due to novel aspects of the tested concepts.

Please help.
Regards

 

[IRstuff]

Why would you risk experimental results by having an inconsistent/unknown surface prep?

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[AligatorAmy]

@IRstuff
Thank you for your question.
As I mentioned earlier, as long as the process can be kicked off (with simplified cleaning) and I can try certain solutions, it will be ok.
Electro cleaning requires extra equipment etc. etc.

 

[IRstuff]

"All brass surface cleaning procedures that I have came across involve the electro cleaning (I understand why)."

Do you? If "all" the procedures require electroless cleaning, then isn't it likely that the finished coating quality is critically dependent on that particular cleaning procedure? Now, if the coating quality is irrelevant to your results, then why do it at all?

TTFN (ta ta for now)
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[AligatorAmy]

@IRstuff
Just to be clear here, by coating quality I mean coating adhesion, wear resistance, etc. But quality is irrelevant here.
What I was hoping is that perhaps someone got the Ni-P process kicked off (for the brass) without the electrocleaning step (even with poor coating quality) what would make my work much simpler.
Whether someone's brass cleaning procedure prior to Ni-P would work or not for my brass material (impact of brass material grade, production method, etc.) that is the separate question, but for me it would be worth to try.

I am working on the specific novel solution for the Ni-P coating solution flow through specific substrate geometries.

P.S. I know what I am doing and why. Thank you.

 

[btrueblood]

Sounds like you are answering your own question...though if you want to be all scientific about it, why not test with/without the electro-cleaning step and verify your postulated result? This is called having a control sample.

 

[AligatorAmy]

@btrueblood
Unfortunately, I do not have the equipment for the electrocleaning. My work is the research in various disciplines and I can devote limited amount of time for this coating resaearch.

The industrial procedures for the brass surface cleaning prior to Ni-P coating are complex. I have came across a few brass cleaning procedures such as this one outlined in the file 1 sent attached.

It is important to note that my brass samples are not 'virgin brass'.
My brass samples are chopped small pieces coming from the tool which is used in the machine (tool working temperature is 200degC, it is in contact with molten polymer). For some reasons I cannot use new brass.
The tool is chopped on small pieces, cleaned on the hot plate from remaining polymer and then cleaned in ultrasonic bath.
Then I apply my cleaning procedure prior to Ni-P coating, which has been so far:
- Etching with use of the mild acid solution (obtained from the company which uses it for the brass etching before the electroplating). Solution tempretature 20degC.
- Rinsing in DI water, for approx. 2 minutes. Water temperature 90degC (this temperature provides pre-heat of the brass prior to coating).
The brass sample surface after cleaning is not shiny, it is still brown, it 'looks' somewhat dirty.

P.S. The same brass samples were forwarded to the Ni-P coating company and the achieved coating quality was excellent (most important coating process was successfully kicked off). Unfortunatelly, none of the coating suppliers can do my experiments with coating.
The company which provided coated samples also applied the electrocleaning process.

In my next coating process I am going to heat up my mild acid etching solution (tried earlier) to 90degC. Hopefully, it will be more efficient then.

 

[btrueblood]

"P.S. The same brass samples were forwarded to the Ni-P coating company and the achieved coating quality was excellent (most important coating process was successfully kicked off). Unfortunately, none of the coating suppliers can do my experiments with coating. The company which provided coated samples also applied the electrocleaning process. "

Ok, so send them another set of samples, and ask them to proceed without the electro-cleaning step? You would then have the two samples to compare (with/without electro-cleaning).