Effect of nano-ZnO particles on the corrosion resistance of polyurethane-based waterborne coatings immersed in sodium chloride solution via EIS technique

Nano-composite coatings were formed by incorporating 3 wt% nano-ZnO in a polyurethane-based waterborne coating. The nano-ZnO based composite coatings were applied on standard phosphated steel panels by cathodic electrodeposition. The electrodeposited nano-composite coatings were then baked for 20 min at 165 °C. To investigate the corrosion resistance of the coatings, the coated panels were immersed in 3.5 wt% NaCl solutions for 2880 h (120 days). The improvement in corrosion performance of the composite coatings was evaluated using electrochemical impedance spectroscopy technique. It was found that the films containing nano-sized ZnO particles show a corrosion resistance of 2 orders of magnitude higher than that of the neat films.     

Corrosion resistance properties of electroless nickel composite coatings

Electroless nickel (EN) composite coatings incorporated with PTFE and/or SiC particles demonstrated significantly improved mechanical and tribological properties as well as low surface energy which are desired for anti-sticking and wear resistant applications. The corrosion resistance of these composite coatings, however, has not been systematically studied and compared. This work aimed to investigate the corrosion characteristics of EN composite coatings using electrochemical measurements which include open circuit potential (OCP), electrochemical impedance spectroscopy and potentiodynamic test. The effects of the co-deposited particles on corrosion behavior of the coatings in 1.0 N H₂SO₄ and 3% NaCl media were investigated. The surface autocatalytic properties and the post-heat-treatment on coating corrosion resistance were also discussed. The results showed that both EN and EN composite coatings demonstrated significant improvement of corrosion resistance in both acidic and salty atmosphere. Ni striking substantially enhanced the corrosion resistance due to the improvement of the surface autocatalytic properties and homogeneity. Proper post-heat-treatment significantly improves the coating density and structure, giving rise to enhanced corrosion resistance.     

Effect of nano-Al2O3 particles on the corrosion behavior of alkyd based waterborne coatings

A modification in the alkyd based waterborne coatings was studied with the addition of 0.05%, 0.1%, 0.2%, and 0.3% nano-Al₂O₃. Corrosion performance of the nano-composite coatings were evaluated by applying these nanocomposites on mild steel substrate and exposing them to salt spray, humidity, and accelerated weathering. Mechanical properties were studied by subjecting the coating to scratch and abrasion test. The results showed that, with an increase in the concentration of nano-Al₂O₃ there was an improvement in the corrosion resistance, UV resistance, and mechanical properties of the coatings indicating the positive effect of addition of nano-Al₂O₃ particles in the coatings. Further, the transparency of the coating was not altered, maintaining the optical clarity of the coating.     

Sol-enhanced electroplating of nanostructured Ni-TiO2 composite coatings—The effects of sol concentration on the mechanical and corrosion properties

Novel sol-enhanced Ni-TiO₂ nano-composite coatings were electroplated by adding a transparent TiO₂ sol into the traditional electroplating Ni solution. It was found that the structure, mechanical properties and corrosion resistance of the nano-composite coatings were largely determined by the sol concentration. The higher sol concentration in the plating electrolyte led to a higher content of TiO₂ nano-particles in the coating matrix. The coating prepared at the sol concentration of 12.5 mL/L had the best microhardness, wear resistance and corrosion resistance. Adding excessive sol to the electrolyte changed the surface microstructure, caused cracking on the coating surface and deteriorated the properties. It was demonstrated that the corrosion resistance of the composite coatings is determined by two factors: surface microstructure and incorporation of TiO₂ nano-particles.     

Effect of nano-ZnO addition on the silicone-modified alkyd-based waterborne coatings on its mechanical and heat-resistance properties

A silicone-modified alkyd-based waterborne coating was developed using hexamethylmethoxymelamine (HMMM) as crosslinking agent and para-toluene sulphonic acid (p-TSA) as catalyst. The crosslinking ratio for resin and HMMM was fixed to 70:30, based on FTIR and DSC studies. Nano-ZnO particles were added to this system in different concentrations. The coatings with nano-ZnO particles were characterized using FTIR and DSC. The nano-composite coatings were applied on mild steel panels and were cured at 130 °C for 30 min. The coatings were evaluated for their mechanical and heat-resistance properties. They were exposed to 350 °C for 10 min followed by water quenching. The process was repeated for 10 cycles. Heat-resistance property of the coatings was examined by TGA. Also, surface morphological changes were assessed using SEM and optical microscopy. It was found that the heat-resistance and mechanical properties of the coatings improved significantly as a function of nano-ZnO addition.     

纳米粉体在化学复合镀中的应用

向化学镀液中加入纳米粉体，使纳米粉体与金属共沉积，可得到性能各异的纳米化学复合镀层。对Ni—P基化学复合镀的沉积机理进行了推测。从高硬度耐磨性、自润滑性、抗高温氧化性、耐腐蚀性等方面，介绍了各种纳米化学复合镀层的研究进展。对纳米粉体的分散性问题进行了探讨，并对纳米化学复合镀层的前景提出了展望。     

改性纳米氧化锌对丙烯酸聚氨酯涂层防腐性能的影响

为了改善纳米ZnO在涂料中的分散性,以钛酸酯偶联剂对其进行改性。研究了丙烯酸聚氨酯清漆、含未改性纳米氧化锌的丙烯酸聚氨酯涂层和添加钛酸酯偶联剂改性后的纳米氧化锌的丙烯酸聚氨酯涂层的防腐蚀性能。结果表明,经过钛酸酯偶联剂改性的纳米ZnO其团聚现象明显消失,与涂料表现出良好的相容性,所得的复合涂层的抗渗透能力明显比清漆和含未改性纳米ZnO复合涂层强。改性纳米ZnO显著提高了丙烯酸聚氨酯涂料的防腐性能。     

环氧／纳米ZnO复合涂层对镁锂合金耐腐蚀性的影响

以聚丙烯酰胺凝胶法制备了纳米ZnO,并对其进行改性,得到了环氧/纳米ZnO复合涂层.采用XRD和SEM对环氧/纳米ZnO复合涂层进行了表征.通过极化曲线和交流阻抗研究了裸基、复合涂层以及经锡酸盐转化处理后涂覆环氧/纳米ZnO的复合涂层的耐蚀性能.结果表明:复合涂层呈明显的两相结构,纳米ZnO分布均匀;复合涂层和锡酸盐转化协同,提高了镁锂合金的耐腐蚀性能.涂层中纳米ZnO质量分数不同,对镁锂合金耐蚀性能有不同的影响,纳米ZnO质量分数为2%时,复合涂层对镁锂合金的保护作用最强.     

化学复合镀的研究现状及镀层的应用

化学复合镀层因复合粒子的性能特点而广泛应用本文就国内外化学复合镀的研究现状和发展趋势进行了综述具体从硬度、耐磨性、自润滑性方面对各种Ni-P基、Ni-B基化学复合镀的工艺研究及镀层结构与性能特点进行了阐述,并认为目前关于化学复合镀的研究仍然集中在耐磨和自润滑镀层方面对不同化学复合镀层的应用做了总结,并对其提出了展望。     

电沉积镍基和铜基纳米复合镀层耐蚀性的研究

通过腐蚀浸泡实验、阳极极化曲线和电化学阻抗谱等测定,探讨了Ni-W-(Si3N4,Al2O3)和Cu-(Al2O3,SiO2)纳米复合镀层的耐蚀性能;通过综合分析,对比添加不同柱子所得镀层的性能,直观地得到添加不同粒子的镍基和铜基纳米复合镀层耐蚀性能的差异.结果表明:Ni-W-Si3N4、Ni-W-Al2O3纳米复合镀层致密度较高,耐蚀性能较好,Cu-Al2O3、Cu-SiO2纳米复合镀层耐蚀性能较差.     

Electrochemical impedance spectroscopy (EIS) study of nano-alumina modified alkyd based waterborne coatings

A nano-composite coating was formed by dispersing nano-Al₂O₃ as pigments in different concentrations, to a specially developed alkyd based waterborne coating. The nano-Al₂O₃ based composite coatings were applied on mild steel substrate by dipping. The dispersion of particles in coating system was investigated by using SEM and AFM techniques. The effect of addition of these nano-pigments on the electrochemical behavior of the coating was investigated in 3.5% NaCl solution, using electrochemical impedance spectroscopy (EIS). It was found that coating modified with higher concentration of nano-Al₂O₃ particles showed comparatively better performance as it was evident from pore resistance (R_p) and coating capacitance (C_c) values after 30 days of exposure. In general, the study showed an improvement in the corrosion resistance of the nano-particle modified coatings as compared to the neat coating, confirming the positive effect of nano-particle addition in coatings.     

Effect of titania particles preparation on the properties of Ni–TiO2 electrodeposited composite coatings

In this paper, the effect of titania particles preparation on the properties of Ni–TiO₂ electrocomposite coatings has been addressed. Titania particles were prepared by precipitation method using titanium tetrachloride as the precursor. The titanyl hydroxide precipitate was subjected to two different calcinations temperatures (400 and 900 °C) to obtain anatase and rutile titania particles. These particles along with commercial anatase titania particles were separately dispersed in nickel sulfamate bath and electrodeposited under identical electroplating conditions to obtain composite coatings. The electrodeposited coatings were evaluated for their microhardness, wettability, corrosion resistance, and tribological behavior. The variation of microhardness with current density exhibited a similar trend for all the three composite coatings. The composite coating containing anatase titania particles exhibited higher microhardness and improved wear resistance. However, the corrosion resistance of the composite coating containing commercial titania powder was superior to that of plain nickel, Ni–TiO₂ composite coatings containing anatase and rutile titania particles. The poor corrosion resistance of these composite coatings was attributed to the higher surface roughness of the coatings. This problem was alleviated by incorporating ball-milled titania powders. The composite coatings with higher surface roughness were modified with a low surface energy material like fluoroalkyl silane to impart hydrophobic and superhydrophobic properties to the coatings. Among these coatings, Ni–TiO₂–9C coating exhibited the highest water contact angle of 157°.     

纳米ZnO/PP及ZnO/CaCO_3/PP复合材料的性能研究

纳米氧化锌(ZnO)与聚丙烯(PP)通过熔融共挤制得了ZnO/PP纳米复合材料.研究了ZnO/PP纳米复合材料的力学、流变学性能与纳米ZnO添加量之间的关系;同时制备了ZnO/CaCO3/PP三元纳米复合材料并对其进行了机械性能和制备成本分析.结果表明,ZnO/PP纳米复合材料的熔体质量流动速率较纯PP有较大程度的提高;纳米CaCO3的加入不但可以降低生产成本,而且可以显著改善体系的冲击韧性;材料的拉伸破坏属于韧性断裂过程.     

镍基纳米复合镀层的研究进展

综述了镍基纳米复合镀层的研究现状。阐述了复合镀层的沉积机理、纳米微粒在复合镀层中的作用机理、纳米微粒在镍基镀液中的分散以及镍基纳米复合镀层的种类和性能。指出了纳米复合镀技术研究中存在的问题和发展方向。     

Study on electrochemical behavior of Nano‐ZnO modified alkyd‐based waterborne coatings

A nano‐composite coating was formed using nano‐ZnO as pigment in different concentrations, to a specially developed alkyd‐based waterborne coating. The nano‐ZnO modified composite coatings were applied on mild steel substrate by dipping. The dispersion of nano‐ZnO particles in coating system was investigated by scanning electron microscopic and atomic force microscopic techniques. The effect of the addition of these nano‐pigments on the electrochemical behavior of the coating was investigated in 3.5% NaCl solution, using electrochemical impedance spectroscopy. Coating modified with higher concentration of nano‐ZnO particles showed comparatively better performance as was evident from the pore resistance (R_po) and coating capacitance (C_c) values after 30 days of exposure. In general, the study showed an improvement in the corrosion resistance of the nano‐particle modified coatings as compared with the neat coating, confirming the positive effect of nano‐particle addition in coatings. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

纳米氧化锌表面改性及其复合水性聚氨酯涂膜性能的研究

以异丙醇为介质,用钛酸酯偶联剂对纳米ZnO进行表面改性,制备改性纳米ZnO/WPU(水性聚氨酯)复合涂膜。通过涂膜的力学性能来评价纳米ZnO的改性效果,讨论了改性纳米ZnO添加量对涂膜的力学性能、耐摩擦性能及耐水性能的影响。结果表明:当偶联剂用量为2%(质量分数),搅拌时间为70 min,反应温度为50℃时,纳米ZnO改性效果最好,当改性纳米ZnO添加量为0.3%(质量分数)时涂膜的综合性能最佳。     

WC的质量浓度对Ni-WC纳米复合镀层耐蚀性及硬度的影响

采用脉冲电沉积方法在304不锈钢基体上制备出Ni-WC纳米复合镀层。研究了WC的质量浓度对Ni-WC纳米复合镀层性能的影响。结果表明:随着WC的质量浓度的增加,Ni-WC纳米复合镀层的耐蚀性先增强后减弱,硬度先增大后减小;当WC的质量浓度为30g/L时,Ni-WC纳米复合镀层的耐蚀性最好,硬度最大。     

Preparation and characterization of UV‐cured hybrid coatings by triethoxysilane‐modified dimethacrylate based on bisphenol‐s epoxy

Novel hybrid oligomers based on a UV‐curable bisphenol‐S epoxy dimethacrylate (DBSMA) were synthetized. DBSMA was modified with various amount of (3‐isocyanatopropyl)triethoxysilane coupling agent. The modification degree of the hybrid oligomer was varied from 0 to70 wt %. The photopolymerization kinetics was monitored by a real‐time infrared spectroscopy. The conversion and rate of hybrid coatings increased with the increase in modification degree. UV‐curable, hard, and transparent organic–inorganic hybrid coatings were prepared. They were performed by the analyses of various properties such as surface and mechanical properties. Results from the mechanical measurements showed that the properties of hybrid coatings improved with the increase in modification degree. The thermal behavior of coatings was also investigated. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and evaluation of epoxy methacrylate UV‐curable coatings containing phthalazinone

Epoxy methacrylate resin (EMA) UV‐curable coatings exhibit high reactivity, low viscosity and excellent chemical resistance in environmentally friendly coatings. A novel EMA containing phthalazinone moieties for high temperature resistant UV‐curable coatings was synthesized. The formulations were cured with hexanediol diacrylate (HDDA) and trimethylol propane triacrylate (TMPTA) as reactive diluents promoted by a photoinitiator, and then interpenetrating polymer networks were generated. The mechanical, chemical and thermal properties of the clear coatings were characterized using Chinese National Standard methods (GB). EMA was used with UV radiation curing in combination with 6.7 wt% of HDDA and 13.4 wt% of TMPTA, and the properties of the cured films were as follows: pencil hardness of 5 H, 30% NaOH resistance for 30 days, 15% HCl resistance for 10 days, 3% NaCl resistance for 30 days and 5% weight loss temperature of 300.5 °C. EMA UV‐curable coatings containing phthalazinone exhibit excellent chemical and thermal stability, and could be potential candidates for UV‐curable zero volatile organic compound coatings applied in the fields of salt spray corrosion, strong radiation and high‐temperature resistance. Copyright © 2009 Society of Chemical Industry     

锌-三氧化二铬复合镀层的特性

采用由氧化锌12g/L、氢氧化钠94 g/L、2-氨基-3-羧基吡啶4.2 g/L、四乙烯五胺17g/L、三乙醇胺2g/L、专利表面活性剂0.5 g/L及碳三氧化二铬(粒径2μm)0～ 11 g/L组成的镀液,于温度50℃、pH 6.5和电流密度4A/dm2的条件下,在低碳钢上电镀Zn-Cr2O3复合镀层.其显微硬度采...