Papers by Keyword: Organic Coating

Abstract: The objective of this paper concerns reducing the zinc metal content in organic coatings while preserving their high mechanical efficiency. The two goals can be achieved by using conductive polymer as components of the protective coating. Polypyrrole (PPy) was investigated as the conductive polymer. PPy was specified using physico-chemical parameters. As a binder, the epoxy ester resin was used. Organic coatings were prepared by combining zinc metal with PPy. The anticorrosive efficiency of the prepared films was evaluated using the results of direct corrosion tests.

Abstract: In this work, an organic double-layer protective coating (ODC) was fabricated through a simple spray process on aluminum and steel. The coating is built as double-layer structure of heat resist base layer and reflective surface layer. Laser with power 10³~10⁴ Wcm^-2 was set to ablate samples for 4s, while the temperature of panels’ back were being measured. Also, reflectivity of the coating was tested. Results demonstrated that reflectivity of ODC was up to 94%, and the panels were less apt to be ablated by laser radiation after coated, while the temperatures measured were substantially lower compared to blank panels with respect to the coating structure and composition.

Abstract: Accelerate the corrosion of the nanometer organic coating by design salt spray test. Research the corrosion resistance of the nanometer organic coating in grotto environment by EIS. The results show that prolong time of the salt spray test, the coating surface become to coarseness, the colour occur slight change, but no blistering and flake away. The Rc and Rt descend, every ten days the corrosion rate of coating augment decuple, at forty days is 3.14μm/a and the steel is not corrosion. The nanometer organic coating behave good protection ability and corrosion resistance in the grotto environment.

Abstract: By adopting coating damage simulation method with electrochemical impedance spectroscopy, the influence of different damage degree K of grey chassis organic coating to its protective performance has been studied. The research found that electrochemical impedance spectroscopy could reflect the damage degree K of the coating. When K is less than or equal to 0.11, the coating still has prefect protective performance, when K is higher than or equal to 2.78, the protective performance of the coating is very low, and when K falls in between, the protective performance of the coating is just favorable; There exist a linear relationship between log (|Z|_0.1Hz) and log K, which may provide a theoretical basis to evaluate the protective performance of such kind of coatings.

Abstract: Most of the steel structures used in industrial and non-industrial applications are exposed to outdoors weathering conditions. Organic coating typically protects them from corrosion. The maintenance actions can be done efficiently only if there is sufficient information of the condition. Therefore, the deterioration of the coating system and its lifetime has to be assessed accurately. This paper focuses on the development of parameters based on adhesion strength useful for that purpose. Three parameters are proposed, namely stress intensity factor, strain energy density, and J-integral.

Abstract: In this dissertation, the electric arc spraying coatings on steel structure were sealed over with the organic coatings addition with nano-sized TiO₂, SiO₂. Some means as light microscope, SEM, energy spectrum and binding force tests were adopted for research the permeability of the sealer. The mechanism for permeable closeness of the sealer was mainly discussed. The results indicated that homogeneous nanofillers can improvement the runnability and permeability of the epikote, stiffen the adhesion between the coatings and the metal substrate. The coating can seal the metal substrate effectively; enhance the protective property of the tectonic systems with electric arc spraying coatings and organic coatings.

Abstract: Electrochemical impedance spectra (EIS) of two kinds of damage rate samples in natural seawater were measured and the relations between coating resistances and phase angles at high frequencies were analyzed. The results indicated that for the coating systems studied, the variation of phase angles at 14 kHz with immersion time was very close to the variation of coating resistance, hence may qualitatively reflect the coating with artificial defect degradation. This approach contains no error in calculation and the special phase angle parameters could be extracted easily from the EIS measured data. These phase angle parameters may be used as quick measurements to evaluate coating with artificial defect performance.

Abstract: Hardened concretes were studied by several spectroscopic techniques (FTIR, Raman and XPS) to determine the surface composition after demoulding and after coating. After demoulding, most of the paste was constituted of calcite but some areas were identified by µRaman as portlandite, ettringite, belite, alite and ferrite phases. The FTIR (in ATR mode) allowed detecting portlandite and C-S-H but it highlighted also organic residues from the demoulding oil. XPS allowed recording interesting atomic ratios to study the extreme surface and the presence of contamination. After post-treatments, the main organic units were determined by FTIR and XPS at the concrete’ surface. Raman was also interesting: no vibration modes of organic species were detected but mineral/hydrated phases were clearly characterized under a thick organic layer. Due to their own specificities, these complementary techniques allowed identifying the mineral/hydrated phases and organic residues/coating at the concrete surfaces.

Abstract: The conservation of historic stone buildings and sculptures is receiving growing attention because of weathering. Now, the techniques for stone conservation are primarily achieved through the use of organic coating treatments. Although some defects of organic protective materials have been recognized, the further shortcoming is still short of awareness. Here we show our investigations of the side effect of organic coating treatments. Some kinds of common stones, including sandstone, tuff, granite, dolomite and marble, were selected as protected objects. Organic silicon compounds were used as protective coatings. The artificial weathering, including salting, freezing and heating, was designed. The treated stones’ decaying was investigated. The results reveal that the treated stone decaying is aggravated. Moreover, the destruction mechanism has been discussed.

Abstract: Magnesium alloys are more and more researched and used as engineering materials in recent years. In the paper, the AZ91D casting magnesium alloy was as basic material by the proper chemical pre-treatment and then was coated with epoxy resin (EP) coatings modified with polyurethane (PU) for protection. The coatings’ adhesion strength, hardness, and corrosion resistance were studied by electronic universal tester, pencil scratch hardness tester, immersion test and electrochemical test. The effect of polyurethane addition on the properties of the coating was ales investigated. The results show that PU / EP ratio of 20% mass fraction can make the basic alloy good mechanical properties and excellent corrosion resistance. The interpenetrating network formed between the epoxy resin modified with polyurethane is of more excellent mechanical and corrosion resistance than pure epoxy resin to protect the magnesium alloy matrix.