Dear Gyorgy Banhegyi ,

Far from pretending to be an expert on the field, i'll give you an answer from the little hindsight (few years) i have on the subject of multicomponent powders high energy ball milling. Although the following answer is focused on high-Energy milling, the different factors presented there should also be considered for more simple milling processes.

First, I would recommend you to check this review article which summarize a lot of parameters affecting the final result of multicomponent powders ball milling (p21-29) :

https://doi.org/10.1016/S0079-6425(99)00010-9

Secondly, as it is suggested in the same article, while milling two powders with different mean diameters and chemical nature, the idea that the smaller component particles should agglomerate on the surface of the larger component particles is incorrect (in most cases). It should be remembered that considering a binary mixture, each component of the mix has its own mechanical properties. Thus, milling will not affect each component the same way, so the biggest particle size component can become the smallest and vice versa.

From this observation, it appears obvious that the starting particle size is not one of the most important factor but rather the mechanical behavior (i.e. ductile or brittle) of each of the two component as it is explained p.32-38.

Now, if you consider possible chemical reactions Inside the mill, component affinity, etc … the "equation" becomes complex and I recommend you to read litterature related to the kind of materials you work with (organic, metals, oxides, …):

High Energy Ball Milling, Mechanochemical processing of nanopowders, 2010 : ISBN 978-1-84569-531-6

I hope this answer will help you

Regards,

Enrique

Dear Enrique, thank you for your valuable comments.