Papers by Keyword: Sol

Abstract: The paper presents the process of sol-gel synthesis of titanium dioxide nanoparticles, the peculiarities of the influence of component composition (titanium precursor content, solvent and stabilizer − surfactant) on the properties of sol and powder obtained on its basis. As a result of the study, the nature of the influence of the type and content of the surfactant in the solution of tetrabutoxytitanium in ethanol on the size of the synthesized particles of titanium dioxide was revealed. The optimal composition of the reaction mixture of TiO–R sol was obtained and the optimal ratio of tetrabutoxytitanium and ethyl alcohol was revealed using which a material with a high content of nanosized titanium dioxide was obtained.

Abstract: Information provided on the color of paint coatings on the mortar substrate, depending on the type of pigment in accordance with the RAL color file. It is shown that presence of glycerin in the composition of the sol of silicate paint promotes an increase in the cohesive strength of coatings, an improvement in the filling of paint, and an improvement in the quality of the appearance of coatings. Information is given on the rheological properties of a silicate paint sol with the addition of glycerin depending on the pigment content. It has been established, that the introduction of glycerin into the paint formulation leads to an increase in the values of the critical volume concentration of the pigment (filler). A model for changing the viscosity of paint from a pigment volume concentration (filler) is proposed.

Abstract: The article presents the results of the study of the properties of the sol of silicate paint. The chemical structure of the polysilicate solutions obtained with the addition of glycerol was studied by IR spectroscopy. It is shown, that the interaction of potassium liquid glass and glycerol is weak and due to the partial replacement of hydrogen ions by potassium ions.

Abstract: In order to improve the wear resistance, ensure the self-lubricating property, Cu-Sn coatings were prepared on the basis of non-cyanide pyrophosphate-stannate and strengthened by combining sol-gel method and composite electroplating technology. In the paper, graphite Sol and Al₂O₃ Sol were added to the Cu-Sn electroplating solution to obtain nanoparticles enhanced Cu-Sn-graphite and Cu-Sn-graphite-Al₂O₃. The effect of graphite Sol and Al₂O₃ Sol addition on composite coatings was investigated, such as surface morphology, micro-hardness and tribological properties. The result shows that the incorporation of the graphite Sol and the Al₂O₃ Sol lead to change the structure of the composite coatings. When the additions of graphite Sol and Al₂O₃ Sol were 110mL/L and 40mL/L respectively, the graphite and Al₂O₃ particles are uniformly distributed in the Cu-Sn matrix and contribute greatly to improve the hardness and tribological properties of Cu-Sn alloy coating.

Abstract: Increasing production of nanomaterials makes the study of nanoparticles fate in the environment of immediate interest. Nanomaterials are known to radically change their properties when released into the environment. In this work, the ability of nanoparticles to form stable dispersions in physiological solutions has been demonstrated. The dispersions were prepared by mixing nanopowders of zinc (13.58 m²/g), copper (24.66 m²/g), aluminum oxides (54.75 m²/g), and zirconium dioxide (8.10 m²/g) with phosphate buffered saline, an isotonic solution of glucose and artificial lysosomal fluid. With the help of laser diffraction method and transmission electron microscopy it was shown that unstable suspensions (with the dispersoid size of 6...49 μm) and aggregative-stable lyosols (with the particles size of 20...300 nm) were formed in dispersions of nanoparticles in physiological media.

Abstract: The rheological properties of konjac glucomannan (KGM) solution were measured by HAAKE Rotational Rheometer, and the results indicated that KGM solution began to transform from Newtonian fluid to non-Newtonian fluid above 0.10 wt%, which represented the overlap of molecular chains. When the concentration exceeded 1.00 wt%, the entanglements of molecular chains became obvious, and the KGM sol formed. Furthermore, the rheological formulas of KGM solution were simulated very regularly, and the parameters of viscosity (η) and non-Newtonian index (n) held the relationship of exponential function to concentration (C), however, the consistency coefficient (κ) displayed a power function, then their concentration-dependence functions were as follows: η=-0.33+1.17e^16.80C, n=0.29+0.79e^-2.56C, and κ=29.11C^3.17. Finally, the rheological properties from diluted solution to KGM sol were revealed.

Abstract: The highly dispersed TiO2 sols composed of anatase crystallites (ca.5 nm) were prepared by peptization of amorphous precipitates with trifluoroactic acid (TFA) during the synthesis. The size and crystallinity of the particles were tuned by the subsequent hydrothermal treatment. The prepared TiO2 nanocrystals were characterized by X-ray diffraction and transmission electron microscopy (TEM). The TEM results indicated that the growth of the crystallites could be inhibited by the increasing addition of TFA and the average sizes of TiO2 nanocrystals were all ultrafine. The degradation of phenol over the nanocrystals after calcination at 500 °C was investigated. The photocatalytic results showed that the sample with a high addition of TFA obtained a better photocatalytic property than that of the commercial TiO2

Abstract: The boehmite sol is prepared with cheap inorganic salt Al(NO₃)₃ and NH₃H₂O. The anodized aluminum alloy was sealed with the boehmite sol. Influences of concentration of Al³⁺, pH and temperature of sol on the properties of sol and the sealed film were studied. The results shows that the viscosity of sol increases and the stability becomes lower with the increase of Al³⁺concentration and pH of sol. The viscosities of sol become lower with the rises of its temperature. The thickness of anodized film increases when sealed with boehmite sol. The thickness value of sealed film increases with the increase of the sol viscosity. The properties of sealed film are better while the color of sol is azury. The corrosion resistance of sealed film was enhanced with the pH rising from 5.5 to 7 at the same concentrate and temperature of sol. The corrosion resistance in acidic solution is improved remarkably for sol sealed film as the sol temperature rises up to 60°C. The time of changing colour for sol sealing film is longer than that of the film sealed by distilled water.

Abstract: Nano-ZnO sol solution was prepared by using Zn(CH3COO)2•2H2O as raw material and β-cyclodextrin (β-CD) was added into the sol, then cotton fabric was treaded with the sol by pad-dry-cure technique. Moreover, the fixation fastness of the composite sol on the fabric was improved by adding the adhesives. Based on the tests of anti-UV, photocatalysis, antibacterial and weight gain rate after adsorbing essence, the results showed that the treated cotton fabrics added with β-CD had better adsorbability to essence, anti-bacterial activity, photocatalytic degradation to formaldehyde and excellent anti-UV property.

Abstract: Alumina sol sealing is one of new green technology for anodized Al alloy. The corrosion mechanism of films sealed by sol and corrosion behaviour of films sealed by sol, Na₂Cr₂O₇, boiling water were analyzed by their curves of open circuit voltage-time (E-T) and potentiodynamic polarization curve. It is found that corrosion tendency of sol sealing film is less than other sealed films by E-T inspection. Fluctuation of open-circuit potential is furious in the immersing prophase and slows down in the anaphase for anodized sealed films. At this time corrosive reactions gradually reach steady state. Open-circuit potential greatly waves for the rough sealed films. Potentiodynamic polarization curves of sealed films show that passive area is the longest for films sealed by sol which has the minimum corrosive current , the passivate current, anodic current and cathode current, but the maximum pitting potential and open-circuit potential. Corrosion parameters are the second for the film sealed by dichromate. Anodic reactions are strongly inhibited by sol sealing films in Cl^- corrosive solution. Sol sealing films weaken cathode O₂ depolarize reaction. Cl^- ions erode anodized Al material on which covered with sol film and produce corrosion. The corrosion of sol-gel film goes through two periods: pitting induced phase and pitting corrosion period.