Contact angles of solid particles on a substrate

The shape of solidified, millimetre size, droplets reflect wetting of the liquid on the solid substrate. The equilibrium shape of a solid particle M on a solid S in a vapour 

It is possible to write this expression in terms of an equivalent contact angle, 0equiv, by comparing with the classical Young-Dupre equation (1.45). Then one gets 

The equilibrium shape of a metallic particle is a sphere with small facets. Thus, the value of 0equiv can also be estimated from the expression tan(0equiv/2) = H/R. 

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