Kinetics of oxide growth

In conclusion, one can say that most anodic oxide films are of a duplex, or even triplex, character, with only the inner portion being composed of a pure anhydrous oxide. In the duplex films, the outer layer contains anions and often a degree of hydration. There could exist a third thin oxide layer at the surface, again with somewhat different properties, which may have a role in the kinetics of oxide growth. 

Figure 31. Correlation of the kinetics of oxide growth with kinetics of sulfate incorporation into the oxide during galvanostatic (a) and potentio-static (b) anodization of A1 in Ff2S04 solutions.166...

Thermal oxidation is a common technique to manipulate macropore shape and realize a variety of novel structures in silicon. The stress and deformation induced by such oxidation, kinetics of oxide growth, and its anisotropy are reviewed. Uniform arrays of both silicon and silica microstructures such as needles and tubules have been realized via thermal oxidation. 

The oxidation of Si by oxygen or water vapor to produce an electrically resistive Si02 layer is an important part of tbe fabrication of semiconductor devices [8], The silica layer that forms is observed to be vitreous rather than crystalline when thin and becomes crystalline as it thickens, as shown schematically in Figure 5.11. The existence of the vitreous oxide is generally explained in terms of the kinetics of oxide growth. However, Jeurgens et al. [9] have recently reanalyzed this case and propose that... 

Work on Cr(llO), under conditions where the kinetics of oxide growth are governed by chromium ion diffusion, shows that below 450°C Cr203 grows on a layer-by-layer basis whereas at higher temperatures the oxide surface roughens and cavities are formed at the metal-oxide interface [49,50]. In situ STM and Auger studies reveal that the oxidation of... 

Oxide surfaces, and in particular oxide films, are versatile substrates for the preparation of model catalysts. Quite a few of these systems show nanoscale reconstructions, which can be employed as templates for the growth of ordered model catalysts of reduced complexity. In order to efficiently control the growth of nanostructured metal particle arrays, two conditions have to be met. First, the template must provide sites of high interaction energy that trap the deposited metals. Second, the kinetics of the growth process must be carefully controlled by choosing... 

The phenomenon of nucleation considered is not limited to metal deposition. The same principles apply to the formation of layers of certain organic adsorbates, and the formation of oxide and similar films. We consider the kinetics of the growth of two-dimensional layers in greater detail. While the three-dimensional case is just as important, the mathematical treatment is more complicated, and the analytical results that have been obtained are based on fairly rough approximations details can be found in Ref. 3. 

In the oxidation of metals, paralinear growth kinetics of oxide layers are known to be a quite usual phenomenon. Such a dependence is observed much less frequently with metallic systems due to three reasons. Firstly, the duration of investigations of the process of oxidation of metals is far longer than that in examining the solid-state interaction of two metals. Secondly, the minimal measurable thickness (or mass) of compound layers which can be detected using available techniques is in the former case much less than in the latter. Thirdly, since this anomalous dependence has no satisfactory explanation from a diffusional viewpoint, experimentalists investigating metallic systems probably prefer not to accentuate on it. 

E. A. Irene, An overview of the kinetics of oxidation of sihcon The very thin Si02 film growth regime, in Passivity of Metals and Semiconductors, M. Froment (ed.), p. 11, Elsevier Science, Amsterdam, 1983. 

In previous sections we have shown that the redistribution of additives at the spherulite boundaries during polymer crystallization leads to the additives uneven distribution, whose form is determined by the kinetics of the growth rejection process. In time, this initial dynamic distribution should relax to an equilibrium form in which the noncrystalline polymer is uniformly permeated by the additive, whose distribution reflects that of the noncrystalline polymer. The relevanoe of these observations to oxidative degradation processes in semi-crystalline polyolefins is discussed in this section. 

A.T. Fromhold and E.F. Cook, Kinetics of oxide films growth on metal crystals electron tunneling and ionic diffusion, Phys. Rev., 1967 158 610-612... 

Stages (I) and (II) are only observable for very low oxygen doses. As soon as the partial pressure becomes elevated, for example equivalent to that of the atmospheric pressure, the oxide layer covers the surface instantly and only the stage (III) remains measurable. The rate of oxide growth then determines the reaction kinetics. 

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