At 5/1/2022 13:13 UTC Nuno Yahoo wrote:
If you look for the reactivity series of metals, you'll find out that the silver in the silver nitrate will exchange places with the copper in the PCB.
The concept of the reactivity series isn't applicable because... long before the silver nitrate can contact the copper to plate out silver, the silver nitrate will react immediately with chloride in the etching solution to precipitate silver chloride. The solution will immediately turn cloudy and is likely to be slow to settle.
Since that silver will not be part of the PCB, but will be a fine elemental silver powder, will fall to the bottom along with the rest of the copper etched.
No... but if it could form fine elemental silver it would immediately, and very rapidly, catalyze the decomposition of the hydrogen peroxide in the solution. There would be a lot of foaming unless the amount of peroxide were very small.
If you're not after the silver, this isn't a concern. Actually speeds up the process.
Won't speed up anything because copper won't be removed by the silver in the first place. The silver nitrate will immediately react with chloride in the solution to form a precipitate of silver chloride, which won't react further because it's essentially insoluble.
The problem comes from the silver chloride that will form once the silver nitrate gets in contact with the chloride acid.
Silver chloride is a white solid substance that will create A BIG MESS everywhere. Sticks to everything and is a pain to clean.
Yes!... at least for some definition of a "BIG MESS." I'd guess big mess, but others might find it not so bad. Couldn't say until actually seeing it... but would rather not find out with my own solution. Even tho the silver concentration is low, for sure the precipitate will heavily cloud the solution. A little silver will look like quite a lot when precipitated as silver chloride.
Not sure if the amount mentioned is, or not, enough to be a problem. Maybe try first with a small sample?
For sure!
Seems to me that the AgNO3 concentration is really low. I would give it a try.
I wouldn't, but if tried the result at worse will just be annoying... requiring settling to remove the silver chloride... and perhaps boiling for some time to grow larger particles of precipitate that will settle faster. At best I can't imagine adding enough peroxide that I couldn't just avoid the precipitate by adding it in the form of 3% or 6% peroxide containing no silver.
JimH
