has anyone measured performance of silver plating solutions?

[coppercone2]

hmm, do you think it has a useful engineering use as a coating? Black brass? Its not super durable though. But for minor handling it seems to be as good as paint in some parts. I can rub it on my forearm with high pressure and there are no streaks. Like pressure across 1cm on the flange lips has a resistance of 0.2 ohms, wheras hard pressure on the clean part obviously is a dead short. SO its not super conductive. A part with a much much thicker layer reads 5 ohms on 1cm.

SO I guess you can say the coating is somewhat conductive.. not good for safety ground anyway.

The conductivity does not seem to change that much compared to the brass that is 'clean' but not really clean (looks like brass), in regards to light pressure with standard DMM test probes. Good coat for a door knob?

Any why was it at first polishing the brass that was on the other side of the piece (not near the electrode)? At least for a while, if you leave it there for 1/2 hour it turns all black with varying thickness.

[IconicPCB]

Some PCB shops produce a board with BLACK OXIDE finish... variety of copper oxide producing a roughened surface texture. Soldermask sticks to it like the proverbial to the blanket.

[coppercone2]

yes, based on my feel for paint, this would be a good bond strength increase.

[coppercone2]

this cleaning solution when dirty is still good for cleaning braze flux/burn off of stuff prior to painting, if you have left overs

[bitter_mike]

Hi coppercone,

I do electroplating bath formulation for a living, so I can probably help with whatever you're trying to do. I skimmed through the previous posts but I'm not immediately seeing what you're trying to do. What are you shooting for here?

[coppercone2]

wanted to know whats going on with home radio electronics and plating

oddball tangent? design considerations for having a go at microwave PCBs and generally increasing Q of coils etc

[bitter_mike]

Ah. Well silver plating improves high frequency performance marginally, as long as you can keep it free of tarnish and other stuff. I think that's been covered in past posts.

What has been less well covered is the impact of putting other coatings over the copper. It looks like there is some talk of nickel plating here and that will make things considerably worse at high frequencies (depending on your particular definition of "high" and how thick the coating is).

As far as electrocleaning/electropolishing goes (they're a bit different) I don't think that would have any significant effect on signal integrity.

For your microwave PCBs, stay away from ENIG. The Ni causes a good amount of insertion loss, though this may be tolerable depending on what you're doing.

Just my thoughts.

[coppercone2]

no it does have an effect on signal integrity, thats why I look to combine the kool amp and the polishing, by definition the kool amp cannot be applied polished,  infact some people want to exonerate ENIG and such, it may not be responsible for the losses people seem to measure

 https://www.microwavejournal.com/blogs/2-judy-warner/post/17127-keepin----it-smooth--how-surface-roughness-impacts-high-performance-pcbs

it makes sense if you do ceramic PCB because the drills and substrates alone are very expensive for good quality, as far as PCB goes, and it seems that it might not be possible to apply the kool amp and then polish it, if the problem is underlying roughness, giving scrub plating a upper operating frequency regime

https://www.linkedin.com/pulse/yak-shaving-judy-warner?articleId=6638124396731080704#comments-6638124396731080704&trk=public_profile_article_view (author has possible bias against roughness)

[coppercone2]

I have been playing around with nickel plating, it looks like the same black crap forms if you run current too high on nickel plate solution. The bottle I bought claimed that 2V is a safe voltage, but when I was running that voltage on a small power supply, it blackened my parts. When I reduced the voltage it worked fine but the plating flaked off (I got lazy and decided that the ultrasonic was too much... . You just can't tell this stuff with intuition and judgment very well... my previous nickel plating while going by the book worked fine). Also, that power supply needs to be calibrated because its my oldest HP unit. I am looking at making a battery powered one for safeys sake to minimize cabling near the solution to the hot plate.

I would guess that I need to reduce current density with the cleaning solution. I ordered some glassware and repaired some clamps and such to make proper fixtures for electropolish/clean/plate and bring temperature control into the mix. If you think about it, it makes sense, because in my previous effort the part facing the electrode turned black (high current density) and the part behind it got polished properly, this is in line with how I understand the current distribution to look like. My setup is also very bootleg.

[coppercone2]

I also wonder if this black burned copper (over current clean) can be used to increase dissipation of the trace while protecting it more so then solder mask, i.e. similar to black anodization of a heat sink.

[helius]

I'm curious if the black finish happens with a carbon electrode. One thought is that you can increase the distance between electrode and the work by placing a baffle between them.