Papers by Keyword: Oxygen Ions

Abstract: Magnesium fluoride (MgF₂) thin films were deposited by electron beam evaporation method and then films were bombarded by oxygen ions for various time to study the evolution of optical properties as a function of bombardment time. The transmittance, structure and morphology of films were measured by UV-vis spectroscopy, XRD and metallographic microscope, respectively. The mean transmittance of films in the visible range decrease significantly with an increase of bombardment time.

Abstract: Oxygen ions are the necessary condition for steel corrosion which occurs when the steel’s passive film is destroyed. Oxygen ions diffusion directly influences steel corrosion rate. The paper, starting from the steel corrosion mechanism, summarized the testing technology and the research progress of oxygen ions diffusion coefficient, analyzed the influencing factors and studied further the effect of oxygen ions diffusion on steel corrosion in concrete. The testing technology of oxygen ion diffusion coefficient is combined with the testing method of steel corrosion rate, and the relationship between oxygen ions diffusion coefficient and steel corrosion rate are established.

Abstract: The effects of the thermally annealing of Bi-Mn-Co-Sb2O3-added ZnO varistors on their electrical degradation were investigated. For the samples with 0.01mol% Sb2O3added and without Sb2O3, no marked difference in the non linearity index of the voltage-current (V-I) characteristics was observed upon electrical degradation for the annealed and nonannealed samples. Upon increasing the amount of Sb2O3 added, the values of  increased after electrical degradation for the annealed samples. Moreover, the value of  after electrical degradation was proportional to the full width at half maximum (FWHM) of the X-ray diffraction peak for Zn2.33Sb0.67O4-type spinel particles under various annealing conditions. The added Sb2O3 did not dissolve in the ZnO grains but became segregated at grain boundaries. Therefore, it is speculated that the increase in the FWHM for the spinel particles is due to the increase in the numbers of fine spinel particles at grain boundaries and triple points.

Abstract: The effects of SnO2 addition on the electrical degradation characteristics of Bi2O3-MnO2-Co3O4 -added ZnO varistors were investigated by field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and voltage-current (V-I) characteristics. The ZnO grain size was made uniform by the addition of SnO2 or Sb2O3. The nonlinearity index α of the V-I characteristic for Bi-Mn-Co-SnO2-added samples was approximately 50 and the varistor voltage was 120~140V/mm. The value of α after the electrical degradation showed a local maximum at approximately 0.1mol% added SnO2 and then showed a local minimum at approximately 0.5mol%, similar to the relative integral intensity of the XRD diffraction peak for the (004) plane for a small amount of SnO2 added. It is suggested that the diffusion of oxygen ions through the grain boundary is affected by the change in crystal orientation of ZnO grains at the grain boundary induced by the addition of a small amount of SnO2.