The Appearance and Growth of Dendrites

The basic cause for the appearance of dendrites is the same as that for the amplification of surface roughness, i.e., the formation of a diffusional field of depositing ions, favoring protrusions developing in the direction of increasing concentration. There are, however, three basic differences which make for the specific appearance of dendritic deposits  

For the intensive growth at a constant velocity of propagation (cf. fig. 20), Barton and Bockris compared the rate of deposition onto a moving para- 

This result can be employed with an equation similar to (87) to obtain current densities at dendrite tips over the whole range of overpotentials and tip radii. 

At low overpotentials (tj RT/F) and relatively large tip radii, the equation reduced to the original one of Barton and Bockris, viz.. 

The use of the full equation indicated the existence of an optimal tip radius at each overpotential for maximum growth rate of the dendrite. 

---