Dendrite-like morphology

TEM images of fatigue failure surfaces (a) very tips of pulled-out SWNTs on a fracture surface. The pulled out SWCNT bundles showed a dendrite-like morphology, believed resulted from splitting of SWCNT rope during fatigue, (b) kink-induced failure of a SWNT bundle, (c) brittle-like failure and (d) ductile-like failure of SWNT bundle. 

Ti-6.6Al-3.5Zr-1.3Si-l.lB. In as-cast state, as-dendritic structure is practically invisible. Lamellar a -structure of matrix is recognized well. Close to uniformly distributed borides have rod-like morphology and fogged like brushwood. Thickness of rods is between 0.1-1.5 pm. Their length is up to 0.2 mm. Fine (0.1-0.3 pm) silicides are uniformly distributed along matrix. Fracture feature is intensive cleavage microcracking of RT and... 

Ti-1.6 wt.% B alloy. In as-cast state, as-dendritic structure is well visible. Structure of matrix is martensite (Fig. 3a). Borides have rod- and strip-like morphology with hexagonal cross-section. Size of rods is around between 0.1 mm and 3 mm in cross-section and a few hundreds of mm length. These rods form strips or plates of a few hundreds of mm width,... 

In VRLA batteries, oxygen reaches the negative plates and is reduced to form water. It also oxidizes the expander and thereby produces carbon dioxide. Consequently, the morphology of the secondary Pb crystals is changed and they become dendrite-like, similar to those shown in Fig. 3.57(a). This results in capacity... 

Hydrothermal synthesis, on the contrary, resulted in nanotube [153] and nano-particle [177] morphologies, as well as in hexagonal star- and dendrite-like 2-D nanostmctures [144] (Figure 19.11a and b). In this case, Mn(N03)2 and Mn(S04)2 salts were used as the most common sources of Mn, with reaction temperatures ranging between 100 and 250 °C. Kim ef al. [143] reported that the addition of a polyvinylpyrolidone (PVP) polymer to the reaction mixture, in combination with the post-treatment (calcination), resulted in a thin layer of a-Mn203 phase covering... 

A variety of patterns was observed when carboxylic acid crystallizes from aqueous solution and mixed with agar or from alcoholic solutions [150]. Oxalic acid crystallizes in fractal-like morphology with fractal dimension D = 1.65. Succinic acid and adipic acid show tree-like and dendritic morphology, respectively. 

The surface films discussed in this section reach a steady state when they are thick enough to stop electron transport. Hence, as the surface films become electrically insulating, the active electrodes reach passivation. In the case of monovalent ions such as lithium, the surface films formed in Li salt solutions (or on Li metal) can conduct Li-ions, and hence, behave in general as a solid electrolyte interphase (the SEI model ). See the basic equations 1-7 related to ion transport through surface films in section la above. The potentiodynamics of SEI electrodes such as Li or Li-C may be characterized by a Tafel-like behavior at a high electrical field and by an Ohmic behavior at the low electrical field. The non-uniform structure of the surface films leads to a non-uniform current distribution, and thereby, Li dissolution from Li electrodes may be characterized by cracks, and Li deposition may be dendritic. The morphology of these processes, directed by the surface films, is dealt with later in this chapter. When bivalent active metals are involved, their surface films cannot conduct the bivalent ions. Thereby, Mg or Ca deposition is impossible in most of the commonly used polar aprotic electrolyte solutions. Mg or Ca dissolution occurs at very high over potentials in which the surface films are broken. Hence, dissolution of multivalent active metals occurs via a breakdown and repair of the surface films. 

Besenhard etal. prepared Sno ygSbo 22 alloy (0.56 Sn+ 0.22 SnSb] with particle size about 200 nm by electroplate and reductive precipitation. Dendrite-like nanosized pure rhombohedral phase P-SnSb alloys were obtained by reductive coprecipitation method (Fig. 5.113. The morphology and particle size can be controlled by choosing solvent, temperature, and stirring conditions. ... 

Figure 1.55. The relationships between the concentration product, (Ba " )i(S04 )i, at the initiation of barite precipitation, and morphologies of barite crystals (Shikazono, 1994). The dashed line represents the boundary between dendritic barite crystals and well-formed rhombohedral, rectangular, and polyhedral barite crystals. The 150°C data are from Shikazono (1994) the others from other investigations. D dendritic (spindle-like, rodlike, star-like, cross-like) barite Dp feather-like dendritic barite W well-formed rectangular, rhombohedral, and polyhedral barite. The boundary between the diffusion-controlled mechanism (Di) and the surface reaction mechanism (S) for barite precipitation at 25°C estimated by Nielsen (1958) The solubility product for barite in 1 molal NaCl solution at 150°C based on data by Helgeson (1969) and Blount (1977). A-B The solubility product for barite in 1 molal NaCl solution from 25 to 150°C based on data by Helgeson (1969).

Several morphologies of dendritic barite, such as feather-like, rod-like, spindlelike, star-like, and cross-like crystals have been recognized when the (niQ. 2+)i(msoj )i values were considerably higher than the equilibrium values, although no detailed studies have been made on the relationship between the various morphologies of dendritic barites and the degree of supersaturation. 

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