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961.
962.
963.
There are growing evidences that Sr-containing calcium phosphate biomaterials can promote better osteo-precursor cell attachment and proliferation than pure calcium phosphate biomaterials. In this study, attempts were made to fabricate two kinds of Sr-substituted calcium phosphate (Ca–Sr–P) coatings on pure magnesium in electrolyte solutions with differing amounts of Sr(NO3)2 for biomedical application. The surface microstructure, composition and chemistry of the coatings were characterized by Scanning Electron Microscope (SEM), Energy-dispersive X-ray Spectroscopy (EDS), and X-ray Diffractometer (XRD), respectively. In addition, electrochemical and immersion tests were performed to evaluate the corrosion resistance of the Ca–Sr–P coated magnesium in phosphate buffered saline solution (PBS). 相似文献
964.
Hot corrosion is one of the main destructive factors in thermal barrier coatings (TBCs) which come as a result of molten salt effect on the coating–gas interface. Hot corrosion behavior of three types of plasma sprayed TBCs was evaluated: usual CSZ, layer composite of CSZ/Micro Al2O3 and layer composite of CSZ/Nano Al2O3 in which Al2O3 was as a topcoat on CSZ layer. Hot corrosion studies of plasma sprayed thermal barrier coatings (TBCs) were conducted in 45 wt% Na2SO4+55 wt% V2O5 molten salt at 1050 °C for 40 h. The graded microstructure of the coatings was examined using scanning electron microscope (SEM) and X-ray diffractometer (XRD) before and after hot corrosion test. The results showed that no damage and hot corrosion products was found on the surface of CSZ/Nano Al2O3 coating and monoclinic ZrO2 fraction was lower in CSZ/Micro Al2O3 coating in comparison with usual CSZ. reaction of molten salts with stabilizers of zirconia (Y2O3 and CeO2) that accompanied by formation of monoclinic zirconia, irregular shape crystals of YVO4, CeVO4 and semi-cubic crystals of CeO2 as hot corrosion products, caused the degradation of CSZ coating in usual CSZ and CSZ/Micro Al2O3 coating. 相似文献
965.
Monica Badila Christoph Jocham Wenbiao Zhang Thomas Schmidt Günter Wuzella Uwe Müller Andreas Kandelbauer 《Progress in Organic Coatings》2014
The powder coating of veneered particle boards by the sequence electrostatic powder application – powder curing via hot pressing is studied in order to create high gloss surfaces. To obtain an appealing aspect, veneer sheets were glued by heat and pressure on top of particle boards and the resulting surfaces were used as carrier substrates for powder coat finishing. Prior to the powder coating, the veneered particle board surfaces were pre-treated by sanding to obtain good uniformity and the boards were stored in a climate chamber at controlled temperature and humidity conditions to adjust an appropriate electrical surface resistance. Characterization of surface texture was done by 3D microscopy. The surface electrical resistance was measured for the six veneers before and after their application on the particle board surface. A transparent powder top-coat was applied electrostatically onto the veneered particle board surface. Curing of the powder was done using a heated press at 130 °C for 8 min and a smooth, glossy coating was obtained on the veneered surfaces. By applying different amounts of powder the coating thickness could be varied and the optimum amount of powder was determined for each veneer type. 相似文献
966.
Christine Bressy Claire Hellio Minh Ngoc Nguyen Brigitte Tanguy Jean-Philippe Maréchal André Margaillan 《Progress in Organic Coatings》2014
This work focuses on the assessment of the erosion properties and antifouling (AF) performance of silyl ester copolymer-based coatings through laboratory and field tests. Silyl ester diblock copolymers were synthesized via the reversible addition-fragmentation chain transfer polymerization and were selected as binders for developing copper-free chemically active coatings. AF coatings were subsequently prepared using biocides (Sea-Nine™ 211, Preventol® A4S, and zinc pyrithione). Laboratory-based bioassays, targeting the growth of selected microorganisms (bacteria and microalgae) and barnacle settlement, highlighted that the silyl ester methacrylic-based binders did not inhibit the growth of microorganisms, are essentially non-toxic to nauplii and reduced the settlement of Amphibalanus amphitrite cyprids. The corresponding biocidal coatings are potent toward bacteria and diatoms but were demonstrated to be toxic against the barnacle larvae. Field test results showed variations with geographical locations: in sub-tropical area, the silyl ester methacrylic-based coatings failed to inhibit the settlement of barnacles; however, field tests performed in Mediterranean Sea for 18 months demonstrated that biocidal silyl ester methacrylic-based coatings were promising candidates. 相似文献
967.
H. Abd El-Wahab M. Abd El-Fattah N. Abd El-Khalik Hesham S. Nassar Mahmoud M. Abdelall 《Progress in Organic Coatings》2014
Coumarin, thiazole and their respective derivative products are some of the oldest and most commonly known class of nitrogen and sulphur containing compounds. In recent years there has been considerable interest in this coumarin–thiazole derivatives, which have been reported to exhibit significant biological activity and are widely used as pharmaceuticals. They are capable of imparting anti-microbial activity properties when incorporated into polymers and polymer composites. In this research, coumarin–thiazole derivative 2-(2-amino-1,3-thiazol-4-yl)-3H benzo[f]chromen-3-one (compound III), was prepared and its structure was confirmed by means of its spectra data. It was also screened for its anti-microbial activity against eight different micro-organisms when physically incorporated into a polyurethane varnish formula. Experimental coatings were manufactured on a laboratory scale and applied by means of a brush on both glass and steel panels. The results of the biological activity indicated that the polyurethane varnishes containing the 2-(2-amino-1,3-thiazol-4-yl)-3H-benzo[f]chromen-3-one (compound III) derivative, exhibit a very good antimicrobial effect. The molecular modeling study revealed that it is biologically safe, it is active and it fulfills Lipinski's rule of five. The physical and mechanical resistances of the polyurethane varnish formulations were also studied to evaluate any drawbacks associated with the addition of the derivative. The studies indicate that the physical incorporation of compound III actually enhances slightly both the physical and mechanical properties. 相似文献
968.
969.
Nano-hardness (Hnano) and nano-elastic modulus (Enano) of corroded coating surface layer were investigated using nano-indentation after epoxy coated specimens were immersed in 5% NaCl solution. The penetration depths (d) of corrosive media into epoxy coating were calculated fitting the curves of (H/E)nano vs. indentation depth (h). EIS spectra of epoxy coated specimens immersed in 5% NaCl solution for different time were measured. Finally the relationship of capacitance (Cf,T) of corroded epoxy coating with the penetration depth of corrosive media was studied. The experimental results showed that the transportation process of corrosive media into epoxy coating was studied through the profiles of (H/E)nano with indentation depth. The penetration depth of corrosive media into the epoxy coating increases rapidly with immersed time firstly, and then increases slowly. The capacitance of corroded epoxy coating has a linear function relationship with the penetration depth of corrosive media into epoxy coating. Nano-indentation can be used to study the transportation process of corrosive media into organic coating. 相似文献
970.
Aliphatic hyperbranched poly(urethane-urea)s with different weight percentages of branch generating moiety were synthesized by a one pot A2 + BC2 approach. Isophorone diisocyanate was used as the A2 type monomer, while a tri-functional dihydroxyamine compound synthesized from ?-caprolactam and diethanol amine acted as the BC2 monomer. Evidence supporting the hyperbranched structure of the synthesized poly(urethane-urea) was obtained from 1H NMR spectra. FTIR study confirmed the nature and extent of hydrogen bonding present in this novel macromolecule. A Gaussian band fitting procedure of the IR band at amide-I region showed that the extent of hydrogen bonding increases with the increase of weight percentage of the tri-functional compound. The tensile strength, elongation at break, impact resistance, scratch hardness and gloss followed an increasing trend with the same. The thermal degradation of the hyperbranched poly(urethane-urea) was found to be dependent on the weight percentage of the BC2 type moiety. The kinetics of thermal degradation studied by the Ozawa method showed that the activation energy required for thermal degradation of hyperbranched polymer is higher than its linear polyurethane analog. The synthesized polymer was found to be biodegradable by Pseudomonas aeruginosa bacteria. The study showed superiority of the hyperbranched structure over the linear one. Thus the results indicated the potential usage of the studied hyperbranched poly(urethane-urea) as an advanced surface coating material. 相似文献