Effect of cerium ion(Ⅲ) on corrosion resistance of organic-inorganic hybrid coating on surface of aluminum-tube used in refrigeration equipment

Organic?inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol?gel method, and the structure of the coating was confirmed by FT-IR. The results of the characterization show that the corrosion resistance of the coating with 1.5 mmol/L cerium ion (III) gains significant improvement, in which the colour retention time of CuSO4 extends to 500 s, the anti-acid and alkali corrosion rates reduce by 67% and 70% compared with the blank one, respectively, and the salt spray tests also show good corrosion resistance. The electrochemical tests demonstrate that the self-corrosion current density and potential of the sample with hybrid coating are about 2.877×10?7 A/cm2 and?0.550 V, respectively. The metallographic and SEM images show that the hybrid coating is uniform and dense, and the EDS analysis confirms that the coating is mainly composed of Al, Si and Ce elements.

Study and Characterization of Organically Modified Silica-Zirconia Anti-Graffiti Coatings Obtained by Sol-Gel

In this work, it is presented the synthesis and characterization of transparent and colorless organic-inorganic hybrid anti-graffiti protective materials obtained by sol-gel method. This type of materials is based on MTES （methyltriethoxysilane）, TPOZ （tetrapropoxide of zirconium） and PDMS （polydimethylsiloxane）. The synthesis has been carried out at 25, 35 and 45 ℃ in order to evaluate the role of temperature in the structure, microstructure and anti-graffiti behavior as well. The incorporation of zirconium within the organic modified silica network, of sols after being gelled and dried, is evident by a shoulder which increased with temperature situated at 950 cml （Si-O-Zr bonds）, and it is homogenously dispersed inside the matrix avoiding the formation of large ZrO2 precipitates. As the temperature increases, the hydrolysis and condensation reactions occur in more extension and thus, the obtained sols are more cross-linked and present more Si-O-Zr linkages. The promising anti-graffiti beha＇4ior of the protectNe hybrids was qualitatively determined being the spot removal higher than 90%.

Fabrication of 2×2 Thermo-Optic Switches with Organic-Inorganic Hybrid Materials Prepared by Sol-Gel Technique

2×2 Mach-Zehnder interferometric thermo-optic switch was fabricated with organic/inorganic hybrid materials by sol-gel technique and direct UV patterning. The switching time of device was measured to be 4.2 ms and switching power 9.3 mW.

Progress in Polymer-Ceramic Hybrid Antifouling Coatings

Simultaneous realization of superior mechanical and antifouling properties is critical for a coating. The use of stereoscopic polysiloxanes in place of linear polysiloxanes to fabricate antifouling coatings can combine properties of organic and inorganic materials, i.e., they can exhibit both high hardness and wear resistance from inorganic components as well as the flexibility and tunability from organic components. This strategy is used to prepare hard yet flexible antifouling coatings or polymer-ceramic hybrid antifouling coatings. In this mini-review, we report the recent advances in this field. Particularly, the effects of stereoscopic polysiloxane structures on their mechanical and antifouling properties are discussed in detail.

Effect of Al_2O_3 and Y_2O_3 on the corrosion behavior of ZrO_2-benzotriazole nanostructured coatings applied on AA2024 via a sol–gel method

zirconia-based nanostructured coatings were deposited on AA2024 to improve the corrosion resistance properties. Three different nanostructured coatings, namely, zirconia–benzotriazole, zirconia–alumina–benzotriazole, and zirconia–yttria–benzotriazole, were applied on AA2024 via a sol–gel method using the dip-coating technique. Next, the coatings were annealed at 150°C after each dipping period. The phases and morphologies of the coatings were investigated using grazing incidence X-ray diffraction(GIXRD), Fourier transform infrared spectroscopy(FT-IR), field emission scanning electron microscopy(FESEM), and atomic force microscopy(AFM). The corrosion properties were evaluated using electrochemical methods, including polarization and electrochemical impedance techniques in 3.5 wt% NaCl solution. The obtained results confirm the formation of homogeneous and crack free zirconia-benzotriazole-based nanostructured coatings. The average roughness values for zirconia-benzotriazole, zirconia-alumina-benzotriazole, and zirconia-yttria-benzotriazole nanostructured coatings were 30, 8, and 6 nm, respectively. The presence of alumina as a stabilizer on zirconia coating was found to have a beneficial impact on the stability of the corrosion resistance for different immersion times. In fact, the addition of alumina resulted in the dominance of the healing behavior in competition with the corrosion process of zirconia-benzotriazole nanostructured coating.

Development of a Novel Hybrid Aluminum-Based Sol-Gel Materials: Application to the Protection of AA2024-T3 Alloys in Alkaline Environment

Extensive research on environmentally complaint sol-gel coatings is currently underway for a wide range of applications. Sol-gel technology combines the synergistic properties of inorganic and organic components to design nanostructured coating materials with advanced physical properties. Through a judicious choice of precursors and additives improved performances, such as chemical resistance or pH stability, it can be achieved. This is of particular interest for copper rich AA 2024-T3 aluminium alloys used on aircraft, where increase in local pH occurs at corrosion sites. This work focuses on improving the alkaline stability and anticorrosion properties of such a sol-gel coatings on AA2024-T3 by incorporating aluminium functionality into hybrid materials prepared from hydrolysis and condensation of 3-methacryloxypropyltrimethoxysilane, zirconium n-propoxide and zirconium/alkoxide precursors. Dynamic light scattering technique was used to study the particle size nature of the sol-gel materials in colloidal form. X-ray photoelectron spectroscopy was used to study the oxidation state of the aluminium and zirconium at the sol-gel coating surface. Field emission scanning electrochemical microscopy coupled with energy dispersive spectroscopy was used to assess the microstructural features. Electrochemical characterisations employing potentiodynamic scanning and electrochemical impedance spectroscopy were performed to investigate the anticorrosion performance of the hybrid sol-gel coatings. The best anti-corrosive protection of AA2024-T3 in an alkaline saline solution (pH = 10) was achieved with materials containing 10 mol% and 15 mol% aluminium doped sol-gel coatings. This study shows that presence of aluminium has a positive effect on alkaline stability of the coatings and is a potential green candidate for the protective coatings on aerospace alloys.

Synthesis and characterization of hybrid organic-inorganic materials based on EA-MAn-APTES and silica

Poly (EA-MAn-APTES)/silica hybrid materials were successfully prepared fromEthyl acrylate (EA), maleic anhydride (MAn) and tetraethoxysilane (TEOS) in the presence of acoupling agent 3-aminopropyltriethoxysilane (APTES),by free-radical solution polymerization and insitu sol-gel process. The mass fraction of TEOS varied from 0 to 25%. The hybrid materials werecharacterized by the methods of FT-IR spectra, solvent extraction, scanning electron microscope (SEM), transmission electron microscope (TEM), differential scanning calorimetry (DSC) andthermogravimetric analysis (TGA) measuring apparatus to get their structures, gel contents,morphologies, particle sizes and thermal performances. The results show that the covalent bonds arebetween organic and inorganic phases, gel contents in the hybrid materials are much higher, theSiO_2 phase is well dispersed in the polymer matrix, silicon dioxide exist at nanoscale in thecomposites and have excellent thermal stability.

Enhanced photocatalytic hydrogen production under visible light of an organic-inorganic hybrid material based on enzo[1,2-b:4,5-b']dithiophene polymer and TiO_(2)

Titanium dioxide(TiO_(2))has been limited in photocatalysis due to its wide band gap(3.2 eV)and limited absorption in the ultraviolet range.Therefore,organic components have been introduced to hybrid with TiO_(2) for enhanced photocatalytic efficiency under visible light.Here,we report that benzo[1,2-b:4,5-b']dithiophene polymer was an ideal organic material for the preparation of a hybrid material with TiO_(2).The energy band gap of the resulting hybrid material decreased to 2.9 eV and the photocatalytic hydrogen production performance reached 745.0μmol g^(-1) h^(-1) under visible light irradiation.Meanwhile,the material still maintained the stability of hydrogen production performance after 40 h of photocatalytic cycles.The analysis of the transient current response and electrochemical impedance revealed that the main reasons for the enhanced water splitting of the hybrid materials were the faster separation of electron hole pairs and the lower recombination of photocarrier ions.Our findings suggest that polythiophene is a promising organic material for exploring hybrid materials with enhanced photocatalytic hydrogen production.

One-step Condensation/copolymerization of VTES and DVB for Self-assembly Bionic Superhydrophobic Surface Coating and Study on Oil-water Separation

Mimicry of nature drives the development of bionic materials.Bionic superhydrophobic materials are a kind of high-efficiency materials to handle oil spills and water pollution.However,the stability of surface coatings of the superhydrophobic materials remains a challenge.Herein,a new category of self-assembly bionic superhydrophobic surface coating was prepared via one-step condensation/copolymerization of vinyltriethoxysilane(VTES)and divinylbenzene(DVB),which realized the close combination of covalent bonds between organic(e.g.DVB)and inorganic matter(e.g.VTES),and avoided the swelling of polydivinylbenzene(PDVB)in the process of collection of oil from water.This organic-inorganic hybrid polymer could self-assembly deposit on the surface of sponge even other substrates.For example,P(VTES-DVB)-Si0_(2)/MS obtained by assembling P(VTES-DVB)-Si0_(2)on the surface of Melamine Sponge(MS)exhibited superhydrophobicity with a Water Contact Angle(WCA)of 157.3,the optimal adsorption capacity of 77 g g 136 g g-1 for diverse oils,and an excellent separation efficiency of 99.3%.Besides,the excellent acid and alkali resistance of P(VTES-DVB)-Si0_(2)/MS suggested the potential value in practical oil-water separation.P(VTES-DVB)-Si0_(2)showed the outstanding hydrophobic performance by using as coating on different substrates.This work provided a new idea about the stable combination of organic and inorganic matter in the surface modification.