The synthesis via interfacial and aqueous solution techniques of zirconium polyethers has been accomplished: Polymer yield seeks a maximum around a molar ratio of Cp2ZrCl2: Diol: Base of 1:1:2. 相似文献
The title subject has been studied by quasi-steady (20 h stabilization) and transient polarization measurements and dc capacitance determinations over potentials from −1 to 2 V (sce) in aqueous solutions of pH 0–13 at 25°C. A few AES investigations of oxide films formed are also included. The quasi-steady data reveal an essentially potential and pH independent passive current and a superimposed current of oxygen evolution appearing already at rather low overvoltages for this reaction. The transients accord with the Cabrera-Mott equation and suggest charge transfer by Zr(IV) ions at sites of relatively fast responding field or current dependent density at the metal/oxide interface (no superpolarization). The transient polarization fits with a value of about 1.5 Å for the activation (half-jump) distance. The capacitance data largely satisfy a simple insulator model, reveal the main charge distribution in the passive zirconium electrode, and combine with previous film thickness data to give about 28/r (r being the roughness factor) for the dielectric constant of the passive film. Comparisons are made to the passive behaviour of titanium and aluminium. 相似文献
Conclusions We investigated the sintering of zirconium dioxide over the temperature range 2000–2350°K as a function of the purity of the material and the defectivity of the oxide crystal lattice. The activation energy of sintering and the vacancy diffusion constant were calculated.The decrease in activation energy resulting from distortion of the crystal lattice is, on the whole, inadequate for activation of sintering.Translated from Ogneupory, No.5, pp. 51–57, May, 1969. 相似文献
Synthesis of zirconium oligomeric polythioethers was effected using aqueous solution and interfacial techniques: The products are insoluble in all tried solvents and possess Zr? OH endgroups but no detectable quantities of R? SH, Zr? Cl, or Zr? N? Et-endgroups. 相似文献