“Smart”micro/nano container-based self-healing coatings on magnesium alloys:A review

Coating technologies are a commonly used way to protect metals against corrosion.However,with more and more severe service environments of materials,many protective coating systems often are not environmentally friendly or toxic as in the case of chromates.Based on the world’s abundant ideal magnesium(Mg)and its alloy,the smart self-healing anticorrosive coating can autonomously restore the damaged part of the coating according to the environmental changes,strengthen the corrosion protection ability,and prolong its service life.This paper reviews the research progress of smart self-healing coatings on Mg alloys.These coatings mostly contain suitable corrosion inhibitors encapsulated into micro/nano containers.Moreover,the different self-healing mechanisms and functionalities of micro/nano containers are discussed.The micro/nano containers range from inorganic nanocontainers such as mesoporous nanoparticles(silica(SiO_(2)),titanium dioxide(TiO_(2)),etc.),over inorganic clays(halloysite,hydrotalcite-like,zeolite),to organic nanocontainers such as polymer microcapsules,nanofibers,chitosan(CS)and cyclodextrin(CD),as well as,carbon materials such as graphene and carbon nanotubes and hybrids such as metal organic frameworks.The functioning of micro/nano containers can be divided in two principal groups:autonomous(based on defect filling and corrosion inhibition)and non-autonomous(based on dynamic bonds and shape memory polymers).Moreover,multi functionalities and composite applications of various micro/nano containers are summarized.At present,significant progress has been made in the preparation methods and technologies of micro/nano containers.Achieving long-term self-healing properties of coatings sensing of coating failure and early warning after self-healing function failure can be expected as the main development direction of self-healing corrosion protection coatings in the future.

Al_2O_3-Y_2O_3 Nano- and Micro-Composite Coatings on Fe-9Cr-Mo Alloy

Al2O3-Y2O3 nano- and micro-composite coatings were deposited on Fe-9Cr-Mo substrates by using sol-gel composite coating technology. The processing includes dipping samples in a sol-gel solution dispersed with fine ceramic powders, which are prepared by high-energy ball milling. High-resolution microscopy （FE-SEM） analyses show that the coating is composed of composite particle clusters with an average diameter of 1μm, and the coating is relatively dense without cracking during drying and sintering stages. XRD analyses show that the oxide coating is mainly composed of α-Al2O3 and γ-Al2O3. The oxidation tests performed at 600℃ in air show that the coatings are provided with much improved resistance against high temperature oxidation and scale spallation. It is indicated that nano-structured composite particles and reactive elements are integrated into the coatings, which plays an important role in preventing agglomeration of nano-particles and initiation of cracks.

Design and micro mechanical properties of nano-SiO_2 strengthened composite coatings towards remanufacturing

Nano-SiO2 particles strengthened Ni-based composite coating was designed and prepared on steel substrate. The structures and nanoparticle content of the nano-SiO2/Ni composite coating were determined by SEM, EDS and TEM; and the micro mechanical properties were tested by nano-indentation technique. The results show that 56% of particles in the solution are dispersed in size of less than 100nm, the content of nanoparticles co-deposited in the coating doubles and structure of the coating is more compact and uniform than that of Ni coating. Nano-SiO2/Ni coating exhibits excellent micro mechanical properties, and the nanohardness and elastic modulus are 7.81GPa and 198GPa, respectively, which are attributed to finer crystal strengthening, dispersion strengthening and high-density dislocation strengthening of nano-SiO2 particles to the composite coatings.

Preparation Nano-Diamond Film by Sol-Gelled Coating Method for Field Emission Display

The mixture of Nano-graphite and organic vehicles doped to Nano-diamond paste. The suitable paste proportion was found. Nano-diamond film (NDF) was prepared by sol-gel coating method on ITO glass at 3000/min. The field emission characteristics of luminance-current, luminance-voltage and luminance-power of Nano-diamond film were analyzed and tested. Comparing these tested curves, the luminance was well proportional to current was got. Theoretic, the inner resistance of NDF field emission display (FED) consumes electric energy and real voltage change between the cathode and the anode of NDF-FED was very small after electrons emit. So the characteristic of NDF-FED was preferable to describe by luminance-current linear relationship, which was advantageous to device tested and designed.

Metal Nano Layer Coating for Improving the Detection and Recognition of Micro-Poisons Using Reflection Spectroscopic Measurement

Metal nano layer coating for increasing the sensitivity of spectroscopic measurements is proposed and experimentally demonstrated in this paper. The metal nano layer will attract the micro-poisons from any measured aqueous sample increasing the concentration of the micro-poison in the vicinity of the surface and significantly improves the sensitivity of the spectroscopic measurement. The demonstration was carried out using Fourier Transform Infra-Red (FTIR) operating in the MIR 400 cm-1 - 4000 cm-1 and 5 nm Gold layer which was grown on silicon oxide substrate. In the experimental demonstration Malathion organophosphate pesticide was used as micro-poison. The spectroscopic measurement proves that Malathion was attracted to the metal nano layer. Furthermore, the absorption lines of Malathion were detected and recognized. This proof of principle can be applied to any Internal Reflection Elements (IRE) and it can be used to purify any aqueous solutions and atmosphere from micro-poisons which will be attracted to the metal Nano layer.

Micro/nano Indentation and Single Grit Diamond Grinding Mechanism on Ultra Pure Fused Silica

The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the influence factors on brittle/ductile transition behavior,the wear of diamond grits in diamond grinding of ultra pure fused silica（UPFS） are investigated by means of micro/nano indentation technique,as well as single grit diamond grinding on an ultra-stiff machine tool,Tetraform ＂C＂.The single grit grinding processes are in-process monitored using acoustic emission（AE） and force dynamometer simultaneously.The wear of diamond grits,morphology and subsurface integrity of the machined groves are examined with atomic force microscope（AFM） and scanning electron microscope（SEM）.The critical brittle/ductile depth of more than 0.5 μm is achieved.When compared to the using roof-like grits,by using pyramidal diamonds leads to higher critical depths of scratch with identical grinding parameters.However,the influence of grit shapes on the critical depth is not significant as supposed.The grinding force increased linearly with depth of cut in the ductile removal regime,but in brittle removal regime,there are large fluctuations instead of forces increase.The SEM photographs of the cross-section profile show that the median cracks dominate the crack patterns beneath the single grooves.Furthermore,The SEM photographs show multi worn patterns of diamond grits,indicating an inhomogeneous wear mechanism of diamond grits in grinding of fused silica with diamond grinding wheels.The proposed research provides the basal technical theory for improving the ultra-precision grinding of UPFS.

Deformation Analysis of Micro/Nano Indentation and Diamond Grinding on Optical Glasses

The previous research of precision grinding optical glasses with electrolytic in process dressing （ELID） technology mainly concentrated on the action of ELID and machining parameters when grinding, which aim at generating very ＂smoothed＂ surfaces and reducing the subsurface damage. However, when grinding spectrosil 2000 and BK7 glass assisted with ELID technology, a deeply comparative study on material removal mechanism and the wheel wear behaviors have not been given yet. In this paper, the micro/nano indentation technique is initially applied for investigating the mechanical properties of optical glasses, whose results are then refereed to evaluate the machinability. In single grit diamond scratching on glasses, the scratching traces display four kinds of scratch characteristics according to different material removal modes. In normal grinding experiments, the result shows BK7 glass has a better machinability than that of spectrosil 2000, corresponding to what the micro/nano indentation vent revealed. Under the same grinding depth parameters, the smaller amplitude of acoustic emission （AE） raw signals, grinding force and grinding force ratio correspond to a better surface quality. While for these two kinds of glasses, with the increasing of grinding depth, the variation trends of the surface roughness, the force ratio, and the AE raw signals are contrary, which should be attributed to different material removal modes. Moreover, the SEM micrographs of used wheels surface indicate that diamond grains on the wheel surface after grinding BK7 glass are worn more severely than that of spectrosil 2000. The proposed research analyzes what happened in the grinding process with different material removal patterns, which can provide a basis for producing high-quality optical glasses and comprehensively evaluate the surface and subsurface integrity of optical glasses.

Research on a Diamond Tip Wear Mechanism in Atomic Force Microscope-based Micro/nano-machining

The object is to investigate the wear of an atomic force microscope (AFM) diamond tip when conducting micro/nano machining on single crystal silicon surface. The experimental research and theoretical analysis were carried out on the worn tip in terms of wear rate, wear mechanism and the effect of the tip wear on micro machining process. The wear rate was calculated as 1.7(10～10mm 3/(N·m) by using a theoretical model combined with the experimental results. Through an integration of an AFM observation on the worn tip features with the FEM simulation of the stress distribution, in addition to the unit cutting force calculation on the AFM diamond tip, the wear mechanism of the AFM diamond tip was concluded as mainly chemical wear, and the wear process was also elaborated as well.

Microtribology of Nitrogen-doped Amorphous Carbon Coatings

The friction, wear and lubrication of carbon nitride coatings on silicon substrates are studied using a spherical diamond counter-face with nano-scale asperities. The first part of this paper clarifies the coating thickness effect on factional behavior of carbon nitride coatings. The second part of this paper reports empirical data on wear properties in repeated sliding contacts through in situ examination and post-sliding observation. The third part will concentrate on wear mechanisms for the transition from "No observable wear particles" to "Wear particle generation." In light of the above tribological study, the application of carbon nitride coatings to MicroElectroMechanical system (MEMS) is therefore discussed from view points of both microtribology and micromachining.

Recent development of LiNi_xCo_yMn_zO_2:Impact of micro/nano structures for imparting improvements in lithium batteries

The recent advancement in the design,synthesis,and fabrication of micro/nano structured LiNixCoyMnzO2 with one-,two-,and three-dimensional morphologies was reviewed.The major goal is to highlight LiNixCoyMnzO2 materials,which have been utilized in lithium ion batteries with enhanced energy and power density,high energy efficiency,superior rate capability and excellent cycling stability resulting from the doping,surface coating,nanocomposites and nano-architecturing.

Nano-diamond/Ni复合电刷镀层的组织形貌的研究

以45#钢为基体,制备了普通镍镀层和nano-diamond/Ni复合刷镀层,采用扫描电镜、能谱仪、X射线衍射仪和金相显微镜等设备对比研究了两种镀层的组织形貌。金相显微镜和扫描电镜分析结果表明,与普通镍镀层相比,nano-diamond/Ni复合刷镀层的表面更加平整、致密,组织更加细化;nano-dia-mond/Ni复合刷镀层表面呈典型的"菜花头"形状,弥散分布的纳米金刚石被镍包裹。能谱仪分析结果表明,nano-diamond/Ni复合刷镀层中纳米颗粒特征元素C的质量分数为7.37%。X射线衍射分析结果表明,随着纳米金刚石加入量的增加,镀层表面晶粒尺寸逐渐减小。

Novel Pretreatment of Hard Metal Substrate for Better Performance of Diamond Coated Cutting Tools

A surface engineering approach for a novel pre-treatment of hard metal tool substrate for optimum adhesion of diamond coatings is presented. Firsfly, an alkaline solution was used to etch the WC grains to generate a rough surface for better mechanical interlocking. Subsequently, surface Co was removed by etching in acid solution. Then the hard metal substrate was boronized to form a compound interlayer which acted as an efficient diffusion barrier to prevent the outward diffusion of Co. Novel nano-microcrystalline composite diamond film coatings with a very smooth surface was deposited on the surface engineering pre-treated hard metal surface. Promising results of measurement in adhesion strength as well as field cutting tests have been obtained.

TC4合金表面Cu/micro-WC复合镀层和Cu/nano-WC复合镀层的性能

在TC4合金表面分别制备了Cu/micro-WC复合镀层和Cu/nano-WC复合镀层。比较了两种复合镀层的表面形貌、化学成分和显微硬度,同时分析了两种复合镀层的摩擦特性。结果表明:两种复合镀层都由Cu、W、C元素组成,显微硬度都明显低于TC4合金的显微硬度;摩擦试验前后,两种复合镀层表面轮廓曲线的形态都存在明显的不同;与Cu/micro-WC复合镀层相比,Cu/nano-WC复合镀层的表面形貌较好,W元素的质量分数较高,耐磨性较强。

Effects of CeO_2 nanoparticles on microstructure and properties of laser cladded NiCoCrAlY coatings

CeO2 nanoparticles(nano-CeO2p) were added into laser cladded NiCoCrAlY coatings on Ni-based superalloy substrate to improve the microstructure and properties.Scanning electron microscope(SEM),X-ray diffractometer(XRD),micro-hardness tester,and heat treatment furnace were employed to investigate their morphologies,phases,micro-hardness and thermal shock resistance,compared with the coating without nanoparticles added.The results showed that the microstructure and properties of the coatings with the addition ...

Construction of Zn-incorporated Micro/Nano Hierarchical Structure Coatings on Tantalum

Tantalum(Ta)alloys have been widely used as bone repair materials duc to their excellent biocompatibility.In present work,zinc(Zn)incorporated ceramic coatings with micro/nano hierarchical structure were successfully fabricated on Ta by micro-arc oxidation and hydrothermal treatment.The content of Zn ions is about(1.35士0.3)wt%.Cortex-like rough morphology(Ra:1.504μm)with irregular vermiform slots can be clearly observed on the surface of Ta.More importantly,the coatings resembling the structure of natural bone can release Zn,Ca,and P ions in a controlled and sustained manner.The corrosion resistance ofTa is greatly improved after functionalized with ceramic coatings,confirming by potentiodynamic polarization tests.The bonding strength between the coatings and substrates can be up to 18.9 N.Furthermore,the surface of MAOs-HT@Ta is covered by bonelike apatite after immersed in Simulated Body Fluid(SBF)for three weeks,showing excellently bioactivity.These results suggest that the innovative Zn-incorporated micro/nano hierarchical coatings on Ta may be used as promising candidates for orthopedic implants.

芯片研制用微纳米尺度温度测量方法及其展望

微纳米尺度温度测量,提供微小尺度区域的高精度温度信息。然而现有的测温技术无法满足芯片性能日益提升的需求,例如以热电偶等为代表的接触式测温具有较高的测量精度,但其响应速率慢难以实现宽场热成像;以红外辐射等为代表的非接触式测温可实现芯片表面的快速热场测量,但测温精度较低、空间分辨率受到波长的限制。因此传统测温方法难以同时满足高精度、微纳米尺度的快速温度测量,亟需寻求新的测温技术。随着量子精密测温技术的发展,基于固态量子自旋效应的金刚石带负电的氮-空位(negatively charged nitrogen-vacancy,NV-)色心测温技术有望解决上述问题,突破现有微纳米尺度测温在芯片研制方面的应用瓶颈。鉴于此,首先综述对比了现有芯片用测温技术的特点和发展现状,而后调研分析了金刚石NV色心测温计量特性及小型化、集成化技术发展趋势,并展望了金刚石NV色心测温在芯片研制领域的技术优势和应用前景,提出其发展面临的挑战。

生物基超疏水涂层的制备及其在包装领域的应用

目的旨在通过全面综述近年来包装领域生物基超疏水涂层的研究进展,使相关研究者快速了解生物基超疏水涂层的构建策略和应用场景,为开发新一代生物基超疏水涂层提供借鉴。方法首先,对超疏水表面的构建策略进行概述,并从生物基材料来源的角度,系统总结生物基超疏水涂层的制备方法、性能特点以及在多功能包装领域的应用情况。其次,探讨目前生物基超疏水涂层面临的主要挑战和未来发展方向。结果生物基超疏水涂层在自清洁、防污、防腐、阻燃、除冰等多功能包装领域显示出优异的性能,为其未来的研究和发展提供了有力支撑。结论得益于生物基材料良好的可降解性和生物相容性,制备全生物基可降解的超疏水涂层将成为未来超疏水涂层重要的研究方向。

微纳织构涂层刀具切削性能研究进展

刀具磨损严重、服役寿命短仍然是切削加工所面临的难题。随着现代制造业的发展,钛合金、高温合金等难加工材料在工业中广泛运用。但由于这些材料具有低导热系数、变形系数小等特点,在机械加工中存在切削力和切削温度高、刀具磨损严重等问题,严重缩短了刀具的服役寿命。通过表面织构技术和表面涂层技术在刀具切削表面置入微纳织构和涂层可以显著改善切削性能;特别是在减小刀具磨损、降低切削力、切削温度以及刀-屑接触界面摩擦因数等方面具有显著效果。系统概述微纳织构涂层刀具的作用机理、切削性能以及应用领域,对微纳织构涂层刀具后续发展有重要推动意义。首先,介绍微纳织构涂层刀具的制备方式。其次,分析总结微纳织构涂层刀具的作用机理,并从抗磨损性、抗粘结性和刀具寿命三个方面总结微纳织构涂层刀具的自身性能。随后,从切削力、切削温度、刀-屑接触处的摩擦因数三个方面总结微纳织构涂层刀具的切削性能。最后对微纳织构涂层刀具在现代制造业中的应用进行阐述。提出在刀具切削表面同时置入微纳织构和涂层的当前研究现状以及未来发展方向,可为进一步研究微纳织构涂层刀具在切削加工中改善切削性能以及加工表面质量与性能提供参考。

金属基体表面超疏水涂层材料的制备及应用研究进展

金属材料因具有优异的综合力学性能,广泛应用于国防军工、工业装备制造等领域中。由于应用环境复杂多变,金属基体材料很容易受到外界环境的影响而发生表面腐蚀和结冰等问题,从而导致关键装备的功能显著下降甚至失效。为解决上述问题,国内外科研人员研发了在金属基体表面沉积超疏水涂层。由于超疏水涂层材料表面通常具有水接触角超过150°和滚动角低于10°的特殊润湿表面特性,要达到超疏水性能,一般需要具备微纳米粗糙结构和低表面能物质修饰两个条件。首先,介绍了制备超疏水涂层材料的常用方法,包括喷涂法、刻蚀法、模板法、沉积法等,并对主要优缺点进行了探讨。然后,在不同制备方法的基础上,进一步探讨了超疏水涂层在防结冰、防腐蚀、减阻、自清洁等领域中有效应用。最后,总结了近年来超疏水涂层材料技术的研究进展,并对未来超疏水涂层材料的研发方向进行了展望。这些研究成果为金属材料在复杂多变的应用环境中提供了更可靠的保护措施,有望提升关键装备的性能和寿命。

基于强氢键作用的超分子微纳米涂层改性滤膜

为解决油水分离滤膜循环使用性差的问题,采用超分子鞣酸-聚乙烯醇(TA-PVA)黏结剂黏附鞣酸-铜(TA-CuⅡ)形成鞣酸-聚乙烯醇-铜(TA-PVA-CuⅡ)涂层改性聚偏氟乙烯(PVDF)膜,制备了具有稳定微纳米涂层的超亲水/水下超疏油膜(TA-PVA-CuⅡ@PVDF)。采用SEM、FTIR、XPS对制备的膜进行了表征,对改性前后PVDF膜的表面润湿性、油水分离性进行了测试,考察了二价铜离子改性时间对TA-PVA-CuⅡ@PVDF循环使用性以及涂层耐久性的影响。结果表明,在亲水性TA-PVA-CuⅡ微纳米涂层的作用下,TA-PVA-CuⅡ@PVDF的水接触角和水下油接触角分别可达到0°和151.0°,其对乳化油的分离膜通量和分离效率最高分别可达1169.30 L/(m^(2)·h)和99.99%,展现出优异的油水分离性能。二价铜离子改性时间为20 min时,TA-PVA-CuⅡ@PVDF循环稳定性和耐久性最佳,具有15次的循环分离次数,并且通量改变率为6.6%。