Fuchun Liu

Fire and Corrosion Resistances of Intumescent Nano-coating Containing Nano-SiO2 in Salt Spray Condition

The nano-concentrates and flame retardant nano-coating were prepared in thhis study. The effect of nano-SiO(2) on the corrosion resistance and fire resistance of ammonium polyphosphate-pentaerythritol-melamine (APP-PER-MEL) coating was investigated by differential thermal analysis (DTA), scanning electron microscopy (SEM), effective thermal conductivity (lambda/d), X-ray photoelectron spectroscopy (XPS) and fire protection test. The chemical action and endothermic effect of ammonium polyphosphate, pentaerythritol and melamine in traditional flame retardant coating were damaged by salt spray condition, whereas the flame-retardant additives in the nano-coating demonstrated the good chemical interaction in salt spray condition. The uniformly dispersed nano-SiO(2) particles could improve corrosion resistance of the coating, and hence nano-coating could remain the good fire-resistant properties even after 500 h salt spray test.

Characterization of self-assembled nano-phase silane-based particle coating

Self-assembled nano-phase silane-based particle coating was prepared through sol-gel technique. Tetramethoxysilane and 3-glycidoxypropyltrimethoxysilane were used as precursors for the self-assembled sol-gel coatings. The silane colloidal particle size was analyzed by laser particle size measurement. The results indicate that the particle size is in nano-scale and the diameter of particles deceases with increasing dilution times. Gel permeation chromatography proves that the relative molecular mass of macromolecule in a referenced sol solution is 1 220-1 240 amu. A simulation model was proposed to study the siloxane structure. Fourier transform infrared spectra of solution and film prove the disappearing of epoxy bond. The results of solid-state (13)C and (29)Si nuclear magnetic resonance experiments indicate the formation of Si-O-Si network. Potentiodynamic analysis shows that the self-assembled coating has excellent corrosion resistance. Salt fog tests prove that 2-methyl piperidine as inhibitor significantly improves the corrosion resistance of the self-assembled coating.

Mechanical and Barrier Properties of Epoxy/ultra-short Glass Fibers Composite Coatings

Epoxy coatings containing different volume fractions of ultra-short glass fibers were prepared successfully. Ultra-short glass fiber not only can improve the hardness, adhesion of the coating, and glass transition temperature ( T g ), but also can decrease the coefficient of thermal expansion (CTE) of the coating. Electrochemical impedance spectroscopy (EIS) was used to evaluate the barrier properties of the coatings containing different volume fractions of ultra-short glass fibers. The EIS results showed that the coating had the best barrier property when it contained 20% (volume fraction) ultra-short glass fibers. The functions of the ultra-short glass fibers in epoxy coating are two-fold: first, they can improve the coating mechanical properties as reinforcement materials; second, they parallel to the substrate and inhibit the corrosive medium to pass through the coating.

Fabrication and Characteristics of a Nano-TiO2 Concentrated Dispersion

A high-concentration dispersion with nanometer TiO2 particles has been fabricated by a hyperdispersant. The particle distribution, composition, viscosity, thermal stability were investigated by transmission electron microscopy, and laser size analyzer, x-ray diffraction, rheometer, differential thermal analysis, and thermogravimetry, respectively. The mean particle size of the nano-TiO2 concentrated dispersion was 72 nm with an especially narrow distribution, and near to monodispersion. The viscosity of 55 wt% nano-TiO2 dispersion is 30 mPa·s at 344 s−1. The dried dispersion composition made from the nano-TiO2 and the hyperdispersant has good thermal stability.

A study on water absorption in freestanding polyurethane films filled with nano-TiO2 pigments by capacitance measurements

The electrochemical impedance spectroscopy (EIS) was used to evaluate the water transport and dielectric properties of polyurethane films filled with nano-TiO(2) at different pigment/base (P/B) values in 0.5 mol/L NaCl solutions. EIS results were compared with gravimetric measurements on the freestanding films. The amount of water absorption showed great discrepancy between the two methods. The diffusion coefficient in the polyurethane film with P/B=30% was the smallest among those filled with nano-TiO(2) pigments. The dielectric constant e of the polyurethane varnish film obtained from the initial capacitance was in the range of typical values of polymers. SEM was used to measure the distribution of nano-TiO(2) particles in the polyurethane films.

Preparation of Montmorillonite by Two-step Intercalation and Its Effect on the Corrosion Resistance of Epoxy Coatings

Two- step intercalation montmorillonites were prepared with montmorillonites(MMTs) as raw material and firstly octadecylamine was used as an modifier to prepare organic MMTs and then 8-hydroxyquinoline as the inhibitor to treat organic MMTs. The MMTs were characterized by infrared spectra and X-ray diffraction. The results show that octadecylamine and 8-hydroxyquinoline have intercalated into the layer of MMTs, and the spacing of MMTs respectively enlarged from 1.17 nm to 1.57 nm and1.82 nm. The resultant MMTs enhanced significantly the corrosion resistance of the epoxy coating according to EIS results.

Improving corrosion resistance of epoxy coatings modified with silane monomers on AZ31D magnesium alloy

Abstract In recent years, there has been growing interest in developing high performance silane containing epoxy coatings. In this work, two silane monomers (3-glycidoxypropyltrimethoxysilane and vinyltrimethoxy silane) were incorporated in epoxy coatings. The results demonstrated that the incorporation of 5 wt-% 3-glycidoxypropyltrimethoxysilane in coating formulation improved the anticorrosive performance of the epoxy coating on AZ31D magnesium alloy. The improving effect of 3-glycidoxypropyltrimethoxysilane was much better than that of vinyltrimethoxy silane, which can be ascribed to the compatibility of the former with epoxy vehicle. The adhesion between epoxy coatings and substrate was also strengthened by addition of the two silane monomers. Ces dernières années, on note un intérêt grandissant dans le développement de revêtements à haute performance de résine époxy contenant du silane. Dans ce travail, on a incorporé deux monomères de silane (3-glycidoxypropyltriméthoxysilane et vinyltriméthoxy silane) dans des revêtements de résine époxy. Les résultats ont démontré que l’incorporation de 5% en poids de 3-glycidoxypropyltriméthoxysilane dans la formule du revêtement améliorait le rendement anti-corrosif du revêtement de résine époxy sur l’alliage au magnésium AZ31D. L’amélioration du 3-glycidoxypropyltriméthoxysilane était bien meilleure que celle du vinyltriméthoxy silane, ce que l’on peut attribuer à la compatibilité du premier avec le véhicule de la résine époxy. L’adhésion entre les revêtements de résine époxy et le substrat était également renforcée par l’addition des deux monomères de silane.

Effect of New Kinds of Sillitin on Performance of Polyurethane Coating for Electric Power Fittings

Polyurethane coatings with two kinds of sillitin, i.e. M type and Z type sillitin respectively as filler were prepared and sprayed on hot dip galvanized steel sheets. The coatings exhibited better mechanical properties than the simple polyurethane coating, i.e. the wear resistance and the hardness of the polyurethane coating may be enhanced by 57.1% and 14.5%, as well as 85.7% and 41.8% for the addition of M type and Z type sillitin respectively. The coatings with the two types of sillitin exhibited also better corrosion resistance. The reason is that two types of sillitin are of a special structure composed of micro- sized granular silica and nano- flake kaolin clay, and the sillitin possesses high amount of nanoflake, which may be beneficial to the enhancement of the permeation resistance and mechanical properties of the coatings.

Anticorrosion Mechanism of Epoxy Coating with Nano-flake Barium Phosphate

Nano-flake barium phosphate was prepared by hydrothermal synthesis, and then the effect of which as pigment on the corrosion behavior of epoxy coating was investigated by means of electrochemical impedance spectroscopy (EIS) and salt spray tests. The results show that the nano-flake barium phosphate in the epoxy coating can react with iron oxide, the corrosion product of metal substraste, to generate an insoluble FePO4 as a barrier on the corrosion spot, thereby to enhance the corrosion resistance of the coating; Among others, an epoxy coating with 5 mass% nano flake barium phosphate shows the highest corrosion resistance.

Influence of Corrosion Inhibitor Carriered Nano-SiO2 on Corrosion Resistance of Epoxy Coating

The 8-hydroxyquinoline (8Q), as a sustained-release corrosion inhibitor was deposited onto nano-particles of mesoporous-silica to prepare 8-hydroxyquinoline-silica (8Q-SiO2) powder. Then the powder was used as pigment to modify epoxy resin to prepare 8Q-SiO2-epoxy resin coat- ing. The prepared 8Q-SiO2was characterized by means of infrared spectrum and ultraviolet absorp- tion spectrum. The corrosion performance of the 8Q-SiO2-epoxy resin coating was examined by salt spray test and electrochemical impedance measurement. The results revealed that the 8Q can enhance the corrosion resistance of epoxy coating, and among others the epoxy coating with 5% (mass fraction) 8Q-SiO2 exhibits the highest corrosion resistance, which may be ascribed to that the 8Q may slowly release from the mesoscopic channels within SiO2 into the epoxy coating and then arrive at the interface coating/substrate to provide corrosion inhibition for the substrate.