scholarly journals ELECTRIC CRYSTALLIZATION OF THIN FILMS OF SODIUM - TUNGSTEN BRONZE

Author(s):  
Борис Магометович Хуболов

В работе рассмотрены вопросы получения тонких пленок натрийвольфрамовых бронз кубической структуры методом электрокристаллизации. Приведены основные параметры полученных пленок. Сняты спектры отражения пленок для неокрашенных и окрашенных пленок. Исследование приповерхностного слоя монокристаллов натрий-вольфрамовых бронз методами протонографии и ядерных реакций показало их высокое структурное совершенство. Анодная и катодная поляризации монокристаллов приводят к изменению структуры их приповерхностного слоя. Обеднение по натрию приповерхностного слоя присутствует и при катодной и при анодной поляризации, и глубина обеднения растет с ростом времени поляризации величины напряжения. Электронографией исследованы тонкие пленки натрийвольфрамовых бронз, установлена аморфная структура свеженапыленных пленок для всех температур подложки. Отжиг электронным лучом приводит к кристаллизации пленок. The paper considers the problems of obtaining thin films of sodium-tungsten bronzes of a cubic structure by the method of electrocrystallization. The main parameters of the obtained films are presented. The reflection spectra of the films were recorded for uncolored and colored films. Investigation of the near-surface layer of sodium-tungsten bronze single crystals by protonography and nuclear reactions showed their high structural perfection. The anodic and cathodic polarizations of single crystals lead to a change in the structure of their surface layer. Depletion in sodium of the nearsurface layer is present at both cathodic and anodic polarization, and the depletion depth increases with increasing polarization time of the voltage value. Thin films of sodium-tungsten bronzes have been investigated by electron diffraction, and the amorphous structure of freshly deposited films has been established for all substrate temperatures. Annealing with an electron beam leads to crystallization of the films.

1977 ◽  
Vol 69 (2) ◽  
pp. 727-730 ◽  
Author(s):  
Marjorie A Langell ◽  
Steven L Bernasek

1979 ◽  
Vol 32 (11) ◽  
pp. 2343 ◽  
Author(s):  
RA Fredlein

The Tafel slopes for oxygen reduction on sodium tungsten bronze electrodes are changed from -4RT/F to -2RT/F by adsorption of platinum from solution. Adsorbed platinum reduces the time to attain steady-state conditions but does not catalyse the reaction. Photo-excitation experiments show that the flat band potential is a function of CH+. Results are interpreted in terms of a thin surface layer of low donor density which is non-degenerate in the potential range of oxygen reduction. It is shown that, without adsorbed platinum, changes in the equilibrium potential difference across the surface layer equal those across the Helmholtz layer due to the presence of hydrogen donors in the lattice and results in -4RT/F Tafel slopes. It is proposed that adsorbed platinum forms surface states pinning the Fermi level at the surface and causing changes in the potential difference to occur entirely across the Helmholtz layer; this results in -2RT/F slopes.


1993 ◽  
pp. 1034-1040 ◽  
Author(s):  
Wakichi KONDO ◽  
Takaaki MANABE ◽  
Toshiya KUMAGAI ◽  
Susumu MIZUTA

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