Application of Wagner's Theory to the Parabolic Growth of Oxides Containing Different Kinds of Defects: I . Pure Oxides

Abstract

Table V. Enthalpies of sublimation of zirconium iodides* AH~s (subl) kcal/mol ZrI 130 ZrI~ 99 ZrI8 63 ZrI, 31.9 * Values are hypothetical because all the iodides, except ZrI~, vaporize incongruently to ZrI,(g), see text.tri-iodides intermediate, in keeping with the relative values of their sublimation enthalpies, which dominates the entropy at those lower temperatures.

Parabolic Growth of Nonuniformly Doped Oxides Containing Aliovalent Impurities on Dilute Alloys

“…The treatment presented here is based on the same theoretical framework as was developed in previous papers for the parabolic growth of pure oxides (15) or uniformly doped oxides (1) during the high temperature oxidation of pure metals or dilute alloys. As shown there, the concentration of each type of lattice and electronic defect is fixed at any point in the scale by the local values of the oxygen activity and impurity concentration through the local electroneutrality condition.…”

Application of Wagner's Theory to the Parabolic Growth of Oxides Containing Different Kinds of Defects: II . Doped Oxides

“…In the presence of Li in substitutional positions in MO, in addition to the usual equations for the formation of the different lattice defects (1), the mechanism of incorporation of the impurity in a normal lattice site according to the reaction (17) Yz 02 + Li20 = 2Li' + 2h" + 20 x [1] must also be considered. Equation [1] shows that the introduction of Li in MO produces an increase in the concentration of the electron holes: this in turn will lower the concentration of the charged metal vacancies or raise that of the charged metal interstitials in oxides containing only one kind of defect, but will affect simultaneously both concentrations in the case of oxides having both kinds of defects, according to Eq. [9]- [10] and [12]-[13] of PartI (1).…”

“…In a previous paper [Part I (1)] we have examined the oxidation behavior of pure metals forming electronically semiconducting oxides with a complex defect structure, extending KrSger's approach (2) to Wagner's theory of parabolic oxidation (3) and considering oxides in which only metal diffusion is important. We extend here the same analysis to the growth of doped oxides on dilute alloys, so that only the base oxide is formed in the process.…”

“…In this paper the effect of a dopant on the kinetics of oxidation of a metal is analyzed considering the particular but unlikely case of a uniform distribution of the dopant in the scale, such as has been considered in the derivation of the Wagner-Hauffe rules (9,10). This simple treatment is, however, extended here to include the case of oxides having a complex defect structure, as has been done in a previous paper (1). The more complete problem of the growth of a doped oxide with a simple or complex defect structure and a nonuniform distribution of the dopant will be dealt with elsewhere (14).…”

From Microurchins to V2O5 Nanowalls: Improved Synthesis through Vanadium Powder and Fast, Selective Adsorption of Methylene Blue

“…Five years later, Arnold and Koonce introduced a method to create metal oxide filaments by annealing the corresponding metals (e.g., platinum, zinc, nickel, palladium, lead, iron, and magnesium) at 300–700 °C in air . Afterward, this research topic attracted the extensive interest of scientists. − With the development of nanoscience and nanotechnology, Jiang et al. found that CuO nanowires can be easily synthesized by heating copper substrates, for example, grids, foils, and wires, at 400–700 °C in air .…”