sk8

Topic: problems with adhesion

we have a small electroplating system set up,

we are having problems with adhesion or thicknessof plate deposited.I will list below what we are doing and any help would be greatly appreciated.I suspect the problem may be with my electrical settings but am not sure

  • we have a 40 ltr tank of silver salts solution mixed with distilled water, it has a ph of 4
  • a degreasing tank heated for thouroughly de greasing and cleaning items. Prior to plating items are wet tested before going any further so no grease is present.
  • rinsing in cold water
  • we immerse in silver solution at room temp for 30 secs at voltage 5,5
  • rinse in water
  • return to silver for 5 -10 mins at voltage of 2
  • drying and then polishing.

the outcome is a burnt item or looks plated but upon buffing the silver deposit is removed and we end up at the begining.

I have treid to research this further and find very confliting information, any info would be greatly recieved, thankyou.

Daniel

Re: problems with adhesion

What type of bath are you using?

DustinGebhardt

Re: problems with adhesion

What is your substrate? Do you have an acid activator before the silver bath? Why do you go into the silver at a high voltage, remove, and then go back in at a lower voltage? Usually you enter a bath at a low voltage then ramp up to a higher voltage.You shouldn't need to remove the part, rinse, and go back in.

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer

Moen

Sanford, NC

sk8

Re: problems with adhesion

Hi There we are using a plastic bath,

we were under the impression that we needed to strike with silver to improve the adhesion of an increased thickness, but this is not working for us.

The substrate is for example a copper tray already plated with epns but with worn areas, we need to replate to achieve total silver plated tray.

No we do not have an acid activator prior to the silver bath.

thankyou for taking the time to help me out

k8

DustinGebhardt

Re: problems with adhesion

If you are trying to re-plate over copper, you will need to go into an acid activator before the silver bath.

A strike is typically a bath with similar properties to the main plating bath, but with less metal and a lower efficiency. Changing the voltage and current in your bath is not going to improve adhesion. If anything, it may hurt adhesion.

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer

Moen

Sanford, NC

sk8

Re: problems with adhesion

Thanks again,

We have a sulphiric acid tank and it can be heated but i have forgotten the temperature and the times, by doing this will the silver adhear to the copper better?


I could also attach the power supply to this but am not sure if this is nessecary please advise??

If we are not going into the silver bath x 2 then what should my voltage and amperage settings be for a small tray for example leaving it in for between 30 secs and 5 mins depending on outcome,

Again thanking you for your time

Regards

k8

Last edited by sk8 (08/16/2011 - 06:55 PM)

DustinGebhardt

Re: problems with adhesion

Yo don't need to heat the acid. It should be about 5% acid at ambient temperature.Immerse the part for about 30 seconds. If the parts show a low of copper oxidation, you will need to go longer.

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer

Moen

Sanford, NC