环境友好型海洋防污涂料的研究现状及展望

为了保护海洋环境、维护海洋生态平衡,环境友好型海洋防污涂料已逐渐取代传统的海洋防污涂料,成为未来海洋防污涂料研究的主导方向。介绍了防污涂料中防污剂的含量、防污涂层的表面自由能、弹性模量、光滑程度、疏水性和pH值等因素对涂料防污效果的影响。综述了环境友好型高分子海洋防污涂料的国内外研究进展,比较了不同防污技术的特点,探讨...     

我国纳米荧光海洋无毒防污涂料的研制项目通过鉴定

据报道,由大连海事大学张占平教授主持研究的“纳米荧光海洋无毒防污涂料的研制“日前通过了交通运输部科技教育司主持召开的研究项目验收鉴定。该项目成功地开发了以PTFE氟树脂复合纳米二氧化钛改性长     

海洋船舶有机硅低表面能防污涂料的研究进展

海洋防污涂料是海洋工程与装备的重要防护材料,对于海洋资源开发利用发挥着极其重要的作用。在现用的海洋防污涂料中,低表面能防污涂料不会对海洋环境产生破坏,是将来的主要发展方向。本文简要介绍了低表面能防污涂料的机理及影响因素,重点论述了有机硅改性不同有机树脂的防污涂料、纳米材料改性有机硅防污涂料和有机硅仿生复合防污体系的技术发展现状,并展望了未来低表面能船舶防污涂料的发展方向。     

低表面能海洋防污涂料的配方复配

以国内低表面能高分子材料为基料,采用配方复配方法制备出一系列的环保型海洋防污涂料。利用接触角测量仪、扫描电子显微镜对产物进行了表征。结果表明:溶剂类型对涂料的漆膜性能存在较大的影响;而涂料中的颜料体积浓度(PVC)是影响涂料漆膜表面张力的主要因素。在临界PVC值时,涂料漆膜的表面张力最大,而在临界PVC值两侧,涂料漆膜的表面张力减小。     

环境友好型海洋船舶防污涂料的研究进展

简述了海洋船舶防污涂料的发展历史以及目前防污涂料的主要类型,介绍了国内外海洋船舶防污涂料的最新发展状况,并对海洋防污涂料的发展趋势进行了展望.     

发展迅速的特种功能涂料

综述了特种功能涂料的类型和作用机理,并对近年在各个领域获得重要应用和极具开发潜力的新型特种功能涂料进行了介绍,指出特种功能涂料必将获得更大的发展。     

环境友好型防污剂及海洋防污涂料的研究进展

本文概括了海洋生物的附着过程及其影响因素,介绍了环境友好型防污剂与海洋防污涂料的发展概况,并对未来环境友好型防污涂料的发展作了展望。     

海洋防污涂料环保化策略研究与发展

随着环保要求的不断提高,含锡自抛光涂料已经于21世纪初被全面禁用,现有的无锡自抛光涂料由于对海洋环境的潜在威胁,也随时可能面临被限制使用的风险。运用各类环保化策略,设计制备绿色环保的海洋防污涂料将是防污涂料的重要发展目标。本文基于传统自抛光防污涂料的两大核心组分防污剂和基体树脂开展了符合环保要求的技术更新方面的论述,同时简要阐述了仿生防污技术、污损释放技术、导电防污技术和紫外防污等海洋防污涂料环保化技术的特点、发展现状及未来发展方向。     

舰船高性能防腐蚀防污涂料研究进展

简要论述了海洋防腐蚀防污涂料的发展历史和研究现状,重点论述了舰船高性能防腐蚀防污涂料的最新研究进展。有机锡自抛光防污涂料被禁止使用之后,基于丙烯酸锌、丙烯酸铜和丙烯酸硅烷酯的自抛光防污涂料得到了广泛应用。基于含防污功能基团树脂的防污涂料、基于降解树脂的防污涂料以及基于表面结构特性的防污涂料技术成为当前防污涂料研究的热点。文中详细报道了降解树脂的结构对降解性能及力学性能影响规律,以及表面结构特性对污损释放型防污涂料防污性能的影响规律。随着环境保护法规的日趋严格,防腐蚀涂料向无溶剂(或高固体)、长效方向发展。报道了提高涂层的湿态附着力和致密性的方法,采用该方法可以大幅提高涂层的力学性能和耐蚀性能,满足了远洋和深海装备发展需求。     

低表面能海洋防污涂层技术及其评价方法

简要介绍了新型、环保的低表面能涂层技术在海洋防污方面的应用及其海洋防污的机理,重点介绍了有机硅涂层、有机氟涂层以及超疏水涂层的国内外研究进展和应用现状,分析讨论了低表面能防污涂层技术的防污性能评价方法,最后展望了低表面能防污涂层技术的应用前景与发展方向.     

Antifouling coatings: recent developments in the design of surfaces that prevent fouling by proteins, bacteria, and marine organisms

The major strategies for designing surfaces that prevent fouling due to proteins, bacteria, and marine organisms are reviewed. Biofouling is of great concern in numerous applications ranging from biosensors to biomedical implants and devices, and from food packaging to industrial and marine equipment. The two major approaches to combat surface fouling are based on either preventing biofoulants from attaching or degrading them. One of the key strategies for imparting adhesion resistance involves the functionalization of surfaces with poly(ethylene glycol) (PEG) or oligo(ethylene glycol). Several alternatives to PEG-based coatings have also been designed over the past decade. While protein-resistant coatings may also resist bacterial attachment and subsequent biofilm formation, in order to overcome the fouling-mediated risk of bacterial infection it is highly desirable to design coatings that are bactericidal. Traditional techniques involve the design of coatings that release biocidal agents, including antibiotics, quaternary ammonium salts (QAS), and silver, into the surrounding aqueous environment. However, the emergence of antibiotic- and silver-resistant pathogenic strains has necessitated the development of alternative strategies. Therefore, other techniques based on the use of polycations, enzymes, nanomaterials, and photoactive agents are being investigated. With regard to marine antifouling coatings, restrictions on the use of biocide-releasing coatings have made the generation of nontoxic antifouling surfaces more important. While considerable progress has been made in the design of antifouling coatings, ongoing research in this area should result in the development of even better antifouling materials in the future.     

Advanced key technologies for magnetron sputtering and PECVD of inorganic and hybrid transparent coatings

Besides classical multilayer systems with alternating low and high refractive indices, reactive pulse magnetron sputtering processes offer various possibilities of depositing gradient films with continuously varying refractive index. Using nanoscale film growth control it is possible to achieve optical filter systems with a defined dependency of refractive index on film thickness, e.g. by sputtering a silicon target in a time variant mixture of oxygen and nitrogen. Also reactive co-sputtering of different target materials such as silicon and tantalum in oxygen is suitable as well. Rugate filters made from SiO_xN_y or Si_xTa_yO_z gradient refractive index profiles find their application in spectroscopy, laser optics and solar concentrator systems.Furthermore polymer substrates are increasingly relevant for the application of optical coatings due to their mechanical and economical advantages. Magnetron PECVD (magPECVD) using HMDSO as precursor allows to deposit carbon containing films with polymer-like properties. Results show the suitability of these coatings as hard coatings or matching layers. Multifunctional coatings with antireflective and scratch-resistant properties were deposited on polymer substrates using a combined magPECVD and sputter deposition process.     

Optical black coatings for space applications

The durability properties of PTX-205 optical black coatings deposited on metallic and non-metallic substrates are studied. The coatings are stable against adverse environmental requirements for space applications. Typically, coatings with 8–11 μ thickness are opaque and have an average reflectance loss (<5%) in the spectral range of 200–1500 nm. The absorption to emission ratio is 1·01.     

Evaluation of coating resistivity for pigmented/unpigmented epoxy coatings under marine alternating hydrostatic pressure

To realize a rapid evaluation of coating degradation under alternating hydrostatic pressure(AHP),appropriate physical models of electrochemical impedance spectroscopy(EIS)data fitting were respectively developed for epoxy coatings with and without pigments,based on their different water absorption behaviours.Power-law model was selected to evaluate the anti-permeability of epoxy varnish(EV)coating,which tends to form through pores in the coating structure.On the other hand,two-layer model based on Young theory was developed to evaluate the anti-permeability of pigmented epoxy coating.Consequently,the resistivity profile with coating thickness was calculated as a critical parameter to describe the anti-permeability of coating at different immersion time.The interpretation of water diffusion dynamics based on different coating structures was also given,which is responsible for the choice of distribution models.     

Deposition of photocatalytic titania coatings on polymeric substrates by HiPIMS

Titania coatings have been deposited onto PET substrates by reactive magnetron sputtering in the HiPIMS (high power impulse magnetron sputtering) mode and for comparison, pulsed DC mode. In the latter case, the substrate showed evidence of melting, but the HiPIMS results were dependent on the characteristics of the power supply when operating under nominally identical conditions. A coating deposited by one of the HiPIMS supplies was found to have a mixed phase structure and to demonstrate a level of photocatalytic activity comparable to conventional coatings which had been post-deposition annealed.     

Corrosion Behavior of Aerosol Thermal Sprayed ZrO2 Coatings

ZrO2 coatings of 2–7 m thickness were obtained by the aerosol thermal spraying process on 316L stainless steel. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) showed that these films consisted of nanocrystalline ZrO2 aggregates with a monoclinic structure. Corrosion tests were performed in aqueous NaCl (0.5 M) and H2SO4 (20 wt%) using potentiodynamic cyclic polarization curves. Surfaces and cross-sections of coated samples were compared with the uncoated substrate. This evaluation indicated decreased pitting of the steel with coating. The protection against corrosion in NaCl solution depended strongly on coating thickness. No protection was found for thicknesses less than 5 m. Meanwhile, a marked reduction of the current density was produced by thicker coatings that acted as an effective corrosion barrier. Coatings thicker than 5 m also provided significant protection against corrosion in H2SO4.     

The production of porous and chemically reactive coatings by magnetron sputtering

High surface area materials can have a number of applications including use as pyrophoric devices, sensors, laser mirrors, filters, thermal barriers and catalysts. The aim of this work was to deposit highly porous thin films capable of undergoing a spontaneous pyrophoric reaction and igniting a suitable substrate material. Magnetron sputtering was the chosen deposition technique as it enables reproducible deposition of coatings, with closely controlled, almost uniform, thickness and morphologies over extended surfaces.A number of magnetron magnetic configurations were investigated and deposition conditions were varied in order to control the surface area of the films and, thereby, optimise the pyrophoric behaviour. As a consequence, pyrophoric coatings were produced with ignition temperatures dependent on the deposition conditions and substrate material/topography. When deposited on combustible substrates, these coating/substrate systems formed simple pyrotechnic devices in a one-stage process. The main thermal signal emitted by these devices was dependent on the substrate material only.     

Erosion of thermal barrier coatings

Abstract

Thermal barrier coatings have been used within gas turbines for over 30 years to extend the life of hot section components. Thermally sprayed ceramics were the first to be introduced and are widely used to coat combustor cans, ductwork, platforms and more recently turbine aerofoils of large industrial engines. The alternative technology, electron beam physical vapour deposition,(EB-PVD) has a more strain-tolerant columnar microstructure and is the only process that can offer satisfactory levels of spall resistance, erosion resistance and surface finish retention for aero-derivative engines.

Whatever technology is used, the thermal barrier must remain intact throughout the turbine life. Erosion may lead to progressive loss of TBC thickness during operation, raising the metal surface temperatures and thus shortening component life. Ballistic damage can lead to total TBC removal.

This paper reviews the erosion behaviour of both thermally sprayed and EB-PVD TBCs relating the observed behaviour to the coating microstructure. A model for the erosion of EB-PVD ceramics is presented that permits the prediction of erosion rates. The model has been validated using a high velocity erosion gas gun rig, both on test coupons and samples removed from coated components. The implications of erosion on component life are discussed in the light of experimental results and the model predictions.     

Photocatalytic activity of reactively sputtered and directly sputtered titania coatings

It is well known that, depending on deposition conditions, the structure of titania coatings may be amorphous, anatase or rutile, or a mixture of phases, and that the anatase phase is the most promising photocatalyst for the degradation of organic pollutants. The formation of anatase depends on the energy delivered to the growing film, which in turn depends on the operating parameters chosen. In this study, titania coatings have been deposited onto glass substrates by pulsed magnetron sputtering both from metallic targets in reactive mode and directly from oxide powder targets. The as-deposited coatings were analysed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and micro-Raman spectroscopy. Selected coatings were then annealed at temperatures in the range of 400–700 °C and re-analysed. The photocatalytic activity of the coatings has been investigated through measurements of the degradation of organic dyes, such as methyl orange, under the influence of UV and fluorescent light sources. Further sets of coatings have been produced both from metallic and powder targets in which the titania is doped with tungsten. These coatings have also been analysed and the influence of the dopant element on photocatalytic activity has been investigated. It has been found that, after annealing, both sputtering processes produced photo-active surfaces and that activity increased with increasing tungsten content over the range tested. Furthermore, the activity of these coatings under exposure to fluorescent lamps was some 50–60% of that observed under exposure to UV lamps.