Exactly how small are you trying to achieve? Are you just trying to go down to ~100 nm or are you trying to achieve ~1 nm? Either way, ball milling is not going to get you down to those sizes. A chemistry approach will most likely be necessary, unless you have access to laser ablation or similar sputtering method.

Silver nanoparticles are obtained by precipitation. There até deverão articles on that

It is possibile with the Formation of Ag NPs in Reverse Micellar Solutions. You can get NPs Ag with the size from ~1nm to 5nm.

Thanks for Question

Alexandra Revina

Thank you for suggestions, I know that the best method to get nanosilver is bottom-up (wet chemical route from solution), but I have silver sphere in the range between 1-5 mm and I would like to decrease it below 100 nm.