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 electroless cleaning (I understand why). However, I wonder whether some recepture could be recommended for CZ121 brass which does not involve electroless 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

 

[jim hardy]

Have you tried this site ? They're a pretty friendly bunch, like PF.

https://www.finishing.com/112/90.shtml

 

[AligatorAmy]

@jim hardy
Thank you for yuor answer.
Yes, I have also asked my question there (it is not posted yet, admin needs to approve it).

 

[jim hardy]

I'd like to learn a little about plating myself, will watch your thread. I hope you'll share how it's done.
My experiments just made black goo on the surface.

 

[Nidum]

Acid dip . Very weak acids will work . Even citric acid or vinegar .

CZ121 is not the best substrate material for any kind of plating . Ideally choose a lead free brass .

Nickel plating usually works better if you flash Copper plate the substrate material first .

 

[AligatorAmy]

@jim hardy
I have obtained same results so far. The surface was covered with something like dark grey easy to scratch coating.
The industrial procedures for the brass surface cleaning prior to Ni-P coating are complex. As I have outlined earlier my goal is to get the process working, even if Ni plating would not be of the best quality and test then some novel concepts of the Ni-P solution flow through specific substrate geometries. Therefore, I am hoping to find some simplified cleaning procedure which would make my work significantly simplier.
I have came across a few brass cleaning procedures such as this one outlined in the file 1 sent attached.

@jim hardy, @Nidum
I need to stay with brass CZ121. I have no choice.
Unfortunatelly, 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, 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.

Thank you Nidum for your advice in regards to the acids. I will try them.
I am also going to heat up my mild acid solution (tried earlier) to 90degC. Hopefully, it will be more efficient then.