Degenerate dendrites

A mixture of dendritic forms (Fig. 25b), degenerate dendrites (Fig. 25c), and holes formed due to the attached hydrogen bubbles (Fig. 25d) was obtained by electrodeposition from solution (II). 

Figure 37. (a) The copper deposit obtained at an overpotential of 1,000 mV from 0.15 MCUSO4 in 0.125 M H2SO4. Quantity of electricity 10 mAh cm 2, (b-d) details from Fig. 37a (b) degenerate dendrite, (c) irregular channels, and (d) the shoulder of the hole. (Reprinted from Ref.67 with permission from Elsevier). 

It is necessary to note that the silver deposits shown in Fig. 16d-f are not similar to ideal silver dendrites,49 but they behave as dendritic ones in regard to their electrochemical properties. Hence, they can be considered as degenerate dendritic deposits. 

The formation of the smaller (and less different to each other) dendrites could be obtained by the increase of deposition overpotential. Unfortunately, the increased overpotential produces the hydrogen evolution in this system and the formation of degenerate dendrites and honeycomb-like deposits.76,77 Nevertheless, the dendritic growth in this system at larger overpotentials is possible by the application of appropriate square-wave pulsating overpotential (PO) regime. For example, the well-developed dendrites were formed with amplitude overpotential of 1,000 mV, deposition pulse of 10 ms, and pause of 100 ms (the pause to pulse ratio 10) (Fig. 26a). They can be well approximated by the cones shown in Fig. 23. Also, superficial holes due to attached hydrogen bubbles were formed between these dendrites, as can be seen from ref.78... 

Dendrites formed around hydrogen bubbles are clearly seen from Fig. 5.10g (tc = 3 ms). Analysis of cross section shown in Fig. 5.1 Oh confirmed formation of more branchy dendrites with a deposition pulse of 5 ms than with 3 ms. The increase of a dispersity of the internal structure is observed with the further increase of deposition pulse. The numerous channels formed around relatively small copper particles and degenerate dendrites are easily observed from Fig. 5.10i (tc = 20 ms). 

A channel structure (Fig. 3.4a), degenerate dendrites (Fig. 3.4b), and cauliflower-like forms (Fig. 3.4c) were formed by copper electrodeposition from 0.15 M CUSO4 in 0.125 M H2SO4. Holes originating... 

Morphologies of copper deposits obtained with deposition pulses of 1, 2, and 50 ms and a pause duration of 10 ms are shown in Fig. 3.5. Holes formed by attached hydrogen bubbles, very branchy dendrites, and small agglomerates of copper grains are formed when the applied deposition pulse was 1 ms (Fig. 3.5a, b). The mixture of holes and degenerate dendrites was formed with a deposition pulse of 2 ms (Fig. 3.5c, d). Honeycomb-like copper stracture constructed of holes and cauliflower-like agglomerates of copper grains formed around them was obtained with a deposition pulse of 50 ms (Fig. 3.5e, f). 

Petit, T. L., Biederman, G. B. and McMullen, P. A. (1980) Neurofibrillary degeneration, dendritic d3fing back, and learning-memory deficits after aluminum administration Implications for brain aging. E p. Neurol 67, 152-162. 

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