Anodic layers formed in polyphosphate electrolytes on rectifying metals

Results obtained in studying the elemental and phase composition of anodic layers formed on titanium, aluminum, niobium, and zirconium under the action of electric discharges in aqueous electrolytes with hexametaphosphate complexes of Ni(II), Mg(II), and Mn(II) are presented.     

Study of the influence of substituents on spectroscopic and photoelectric properties of zinc phthalocyanines

In this paper we describe conversion of light energy into electric energy in a photoelectrochemical cell containing zinc phthalocyanine (ZnPc) dyes. For all dyes investigated in liquid polyvinyl alcohol with dimethyl sulfoxide solution and located in the photoelectrochemical cell the following measurements have been done: absorption, fluorescence, photoacoustic spectra, photovoltaic spectra, kinetics of photocurrent and current–voltage characteristics. It has been shown that all dyes located in the photoelectrochemical cell are able to convert light into electric energy but with different effectiveness. The influence of substituted different peripheral groups to ZnPc core and the correlation between the molecular structure and effectiveness of solar to electric energy conversion were observed and described. The unique behavior of ZnPc substituted with fluorines was indicated.     

Thomas Fermi model of finite nuclei

A relativistic Thomas-Fermi model of finite nuclei is considered. The effective nuclear interaction is mediated by exchanges of isoscalar scalar and vector mesons. We include also a self-interaction of the scalar meson field and the Coulomb repulsion of the protons. The parameters of the model are constrained by the average nuclear properties. The Thomas-fermi equations are solved numerically for finite, stable nuclei. The particular case of ₂₀₈⁸²Pb is considered in more detail.     

Effect of the Polyphosphate/Me Molar Ratio in an Aqueous Electrolyte on the Composition of Anodic-Spark Layers at Aluminum Alloys

The manner in which the molar ratio n = [sodium polyphosphate]/[Me cation] in aqueous electrolytes is related to the thickness h and the element content (EC) of anodic layers formed on aluminum and its alloys during electric microbreakdowns (sparks, microarcs) is established. The polyphosphate structure, the electrolyte pH, and the nature and charge of Me cation do not affect dependences of EC and h on n in the case of Mn(II), Pb(II), Mg(II), Zn(II), Ni(II), Y(III), and Eu(III). The film growth mechanism changes with n. The incorporation of P, Me(II), or Me(III) is due to thermolysis of precipitate from electrolyte containing hydrated polyphosphates of Me(II) or Me(III), the thermolysis occurring at the anode under the action of electric breakdowns.     

Optical Properties of ZrO2–Containing Anodic Coatings on Aluminum

Anodic oxide coatings (AOC) formed at the potentials of spark breakdowns in aqueous solutions of potassium hexafluorozirconate (K₂ZrF₆) contain up to 36 wt.% of Zr. The modification of ZrO₂ in AOC is tetragonal. The reflection coefficients of AOC have been measured in the range 430–670 nm. After UV irradiation for a few hours the reflection coefficient decreases by several percent. The treatment of AOC in a solution containing F^– and [Fe(CN)]^3– ions leads to a change in the aluminum and zirconium concentrations in the surface layer and to an increase of the AOC reflectivity.     

Non-radiative deactivation pathways of subphthalocyanine and subnaphthalocyanine dyes and of their mixture

Subphthalocyanine and subnaphthalocyanine dyes and their mixture were investigated by means of the spectroscopic and photoelectric methods. Absorption, fluorescence, steady-state and time-resolved photothermal measurements for the dyes and their mixture were done in order to get information about the radiative and non-radiative deactivation processes as competetive processes to charge separation. It was shown that energy transfer between the dyes improved the photocurrent generation in photoelectrochemical cells (PEC) based on In(2)O(3) and SnO(2) as an electrode. The possible participation of the dye triplet states in non-radiative processes was discussed.     

On Composition of Anodic-Spark Coatings Formed on Aluminum Alloys in Electrolytes with Polyphosphate Complexes of Metals

Anodic layers containing M(II) phosphates, e.g., Mg₃(PO₄)₂, Mn₂P₂O₇, Mn(PO₃)₂, and NaZnPO₄, were obtained.     

Time-resolved photocurrent generation in a photoelectrochemical cell with phthalocyanine

The kinetics of photocurrent generated in the photoelectrochemical cell (PEC) with phthalocyanine (Pc) dyes in the microsecond time scale was discussed. The shape of the kinetics is rather complex and it was discussed in terms of molecular phenomena and electrochemical processes occurring after laser flash illumination. Time constants were calculated from the photocurrent decay curves and at least three time components were well recognized (rise in 0.40 micros, declining in 0.40-0.45 micros and secondary increase in about 2 micros). The shape of the kinetics was discussed in terms of dye singlet and triplet state participation in photocurrent generation and also in terms of creation of the Helmholtz-Goy double layer at the dye layer-semiconductor interface. The alteration in shape of the Helmholtz-Goy double layer in photoelectrochemical cell after laser pulse was also discussed.     

Zirconium-containing oxide layers on titanium

The plasma electrolytic deposition (PED) method is shown to be useful for the formation of zirconium-containing layers in electrolytes containing Zr(IV) polyphosphate complexes. Titanium phosphates, binary titanium-zirconium phosphates, titanium phosphates, and zirconium phosphates crystallize during annealing of PED layers in air. The element and phase compositions depend on the molar ratio n=[polyphosphate]/[Zr⁴⁺] in the bulk of the electrolyte.