超细SiC片晶的制备方法

超细SiC片晶由于其高强度、高弹性模量和高导热系数已成为替代价值昂贵、制备技术复杂的SiC晶须的理想的增韧材料SiC片晶的制备方法有化学制备法和机械制备法。本文中详细介绍了用机械方法制备SiC片晶的设备与工艺过程,阐述了各种制备方法的工作原理及其优缺点,通过对各种制备方法的比较得出采用气流磨与分级机结合工艺是目前制备系列超细SiC片晶有效的和最经济的生产工艺。     

模板法制备纳米片状银粉的粒径与形貌控制

模板合成法广泛应用于纳米材料的研究.表面活性剂在水溶液中可以形成多种自组装胶体结构,被认为是纳米材料制备的有效模板,对非球形贵金属纳米粉体的制备很有效.对片状银粉的制备方法进行了总结,特别是纳米片状银粉的模板法制备,探讨了模板法制备纳米片状银粉的原理与影响因素,分析了模板法制备纳米片状银粉的粒径与形貌控制关键,并对纳米片状银粉粒径与形貌控制提出了一些建议.     

IPMC人工肌肉的制备工艺研究与改进

研究了Nafion117质子交换膜的成膜过程与IPMC人工肌肉的制备过程.制备不同厚度的Nafion膜,在此基础上使用化学沉积法制备IPMC.制备主要分为前期预处理、主化学镀反应和次化学镀反应.由于在制备过程中膜表面产生气泡,需要高速搅拌,既要考虑到气泡快速溢出,又要使Nafion膜不与搅拌棒接触产生划痕,因此采用立式...     

纳米储氢合金制备方法的研究进展

纳米储氢合金的热力学与动力学性能明显超过了相应的微米级合金 ,引起了储氢合金研究者的关注 ,而目前纳米储氢合金的制备方法仅集中于球磨法。本文总结了纳米储氢合金颗粒与复合材料的制备方法 ;并从纳米材料制备技术的角度 ,对潜在的纳米储氢合金的制备方法进行了评述     

连续流变挤压技术在制备高性能铝材中的应用

目的探索铝材短流程制备工艺,制备出高性能铝合金材料。方法采用连续流变挤压成形技术制备Al-Ti-B晶粒细化剂与Al-Sc-Zr耐热铝合金导线;利用提出的连续流变挤压与累积连续挤压法,制备超细晶金属材料。结果采用连续流变挤压成形技术制备Al-Ti-B晶粒细化剂,其细化效果优于国外同类产品,且制备流程短、成本低;制备出的高性能的Al-Sc-Zr耐热铝合金导线,其抗拉强度、伸长率和导电率分别达到223 MPa、7.1%和60.5%IACS,并且可在230℃的温度下长期运行,相比于日本耐热铝合金导线,其抗拉强度、伸长率与导电率分别提高了39.4%,255%,0.83%;采用连续挤压技术制备的Al-Sc-Zr合金杆,经过累积连续挤压后,合金晶粒尺寸从100μm细化至800 nm,得到了超细晶Al-Sc-Zr合金。结论连续流变挤压技术制备铝材工艺流程短、产品性能优良,能连续高效制备铝合金超细晶材。     

热喷涂技术制备功能梯度材料涂层的发展状况

介绍了热喷涂技术制备功能梯度材料涂层的研究与发展状况,分析了各种热喷涂方法制备功能梯度涂层的技术与工艺特点,指出了各自的优势与不足;同时还介绍了20世纪90年代末发展起来的自蔓延高温合成技术与热喷涂技术相融合而形成的反应热喷涂技术制备功能梯度材料涂层的最新研究动态,并展望了热喷涂制备功能梯度材料涂层的发展前景.     

高温超导薄膜微细图形制备工艺的研究进展

高温超导薄膜具有良好的物理性能,其微细图形在微电子器件中有非常广泛的应用.概述了高温超导薄膜微细图形的制备工艺及研究进展,重点介绍了高温超导薄膜微细图形制备方法中的光刻法、改性工艺、耐熔微掩膜制备法和Sol-gel法与化学修饰法相结合的基本原理、工艺特点及最新研究进展.首次把Sol-gel法与化学修饰法相结合制备薄膜的微细图形的工艺用于高温超导薄膜微细图形的制备中.     

Four Significaut Items on Processing Science were Successfully Appraised

四个制备科学重点项目通过评议材料的制备科学问题是材料科学与工程发展的重要组成部分,特别对于新型材料,如何通过制备过程的基础性研究来获得有害缺陷少、可靠性强、性能好、价格便宜的材料,是当前国际上十分关注的问题.为了引起我国材料研究科学家对材料制备的研究足够重视,加强材料制备研究的多学科的交叉与衔接,以及深入的理论和规律性研究,国家自然科学基金委员会在八五期间最后一批重点项目中设立了四项关于材料制备科学....     

柔性传感器的制备

柔性传感器是近年来医用传感器的研究核心,随着可穿戴设备的进一步发展,柔性传感器的量产与制备成为另一个热点话题,本文主要从柔性传感器的结构与制备流程,介绍相关的技术与研究成果,并分析柔性传感器制备过程中的一些技术难点和发展方向。     

塑料薄膜专用抗菌母粒制备及其应用

本文介绍了一种专用于制备抗菌塑料薄膜抗茵母粒。采用含银共容组合物与高熔融指数的高分子树脂捏合,然后再与载体树脂共混,经双螺杆挤出机熔融挤出,切粒。采用所制备的母粒与PE树脂混合,制备了抗茵性能良好的聚乙烯薄膜。     

Carbon Nanotubes Based Devices and Sensors

The dimensionality of a system has a profound influence on its physical behavior, especially for nanostructured materials where at least one of the dimensions is less than 100 nm and, in many instances, the size is comparable with the size of many fundamental physical quantities. Carbon-based nanostructured materials exhibit unique mechanical, electrical, and optical characteristics that may result in many unique device designs. The materials are biocompatible, chemically inert, yet capable of altering electronic properties in presence of some chemical species, dimensionally compatible with bio-molecules, and have interesting electronic characteristics; hence, rendering them as potential chemical and biosensors. A recent heightened awareness of the potential for inadvertent or deliberate contamination of environment and food and agricultural products has made decentralized sensing an important issue for several federal agencies. Recent progress in nanostructured materials and its possible applications in chemical and biological sensors could have a significant impact on data collection, processing, and recognition. Our present and ongoing investigation is aimed towards evaluating the applications of carbon-based nanotubes, nanowires, and nanoporous materials in unique devices and sensors, based on its unique characteristics, morphological flexibility, and biocompatibility.     

Modification of nanostructured materials for biomedical applications

Adaptation (or incorporation) of nanostructured materials into biomedical devices and systems has been of great interest in recent years. Through the modification of existing nanostructured materials one can control and tailor the properties of such materials in a predictable manner, and impart them with biological properties and functionalities to better suit their integration with biomedical systems. These modified nanostructured materials can bring new and unique capabilities to a variety of biomedical applications ranging from implant engineering and modulated drug delivery, to clinical biosensors and diagnostics. This review describes recent advances of nanostructured materials for biomedical applications. The methods and technologies used to modify nanostructured materials are summarized briefly, while several current interests in biomedical applications for modified and functionalized nanostructured materials are emphasized.     

Nanotechnology and health safety--toxicity and risk assessments of nanostructured materials on human health

The field of nanotechnology has recently emerged as the most commercially viable technology of this century because of its wide-ranging applications in our daily lives. Man-made nanostructured materials such as fullerenes, nanoparticles, nanopowders, nanotubes, nanowires, nanorods, nanofibers, quantum dots, dendrimers, nanoclusters, nanocrystals, and nanocomposites are globally produced in large quantities due to their wide potential applications, e.g., in skincare and consumer products, healthcare, electronics, photonics, biotechnology, engineering products, pharmaceuticals, drug delivery, and agriculture. Human exposure to these nanostructured materials is inevitable, as they can enter the body through the lungs or other organs via food, drink, and medicine and affect different organs and tissues such as the brain, liver, kidney, heart, colon, spleen, bone, blood, etc., and may cause cytotoxic effects, e.g., deformation and inhibition of cell growth leading to various diseases in humans and animals. Since a very wide variety of nanostructured materials exits, their interactions with biological systems and toxicity largely depend upon their properties, such as size, concentration, solubility, chemical and biological properties, and stability. The toxicity of nanostructured materials could be reduced by chemical approaches such by surface treatment, functionalization, and composite formation. This review summarizes the sources of various nanostructured materials and their human exposure, biocompatibility in relation to potential toxicological effects, risk assessment, and safety evaluation on human and animal health as well as on the environment.     

Melt Infiltration: an Emerging Technique for the Preparation of Novel Functional Nanostructured Materials

The rapidly expanding toolbox for design and preparation is a major driving force for the advances in nanomaterials science and technology. Melt infiltration originates from the field of ceramic nanomaterials and is based on the infiltration of porous matrices with the melt of an active phase or precursor. In recent years, it has become a technique for the preparation of advanced materials: nanocomposites, pore‐confined nanoparticles, ordered mesoporous and nanostructured materials. Although certain restrictions apply, mostly related to the melting behavior of the infiltrate and its interaction with the matrix, this review illustrates that it is applicable to a wide range of materials, including metals, polymers, ceramics, and metal hydrides and oxides. Melt infiltration provides an alternative to classical gas‐phase and solution‐based preparation methods, facilitating in several cases extended control over the nanostructure of the materials. This review starts with a concise discussion on the physical and chemical principles for melt infiltration, and the practical aspects. In the second part of this contribution, specific examples are discussed of nanostructured functional materials with applications in energy storage and conversion, catalysis, and as optical and structural materials and emerging materials with interesting new physical and chemical properties. Melt infiltration is a useful preparation route for material scientists from different fields, and we hope this review may inspire the search and discovery of novel nanostructured materials.     

Nanostructured electronic and magnetic materials

Research and development in nanostructured materials is one of the most intensely studied areas in science. As a result of concerted R & D efforts, nanostructured electronic and magnetic materials have achieved commercial success. Specific examples of novel industrially important nanostructured electronic and magnetic materials are provided. Advantages of nanocrystalline magnetic materials in the context of both materials and devices are discussed. Several high technology examples of the use of nanostructured magnetic materials are presented. Methods of processing nanostructured materials are described and the examples of sol gel, rapid solidification and powder injection moulding as potential processing methods for making nanostructured materials are outlined. Some opportunities and challenges are discussed.     

Recent advances and remaining challenges of nanostructured materials for hydrogen storage applications

The rapid and extensive development of advanced nanostructures and nanotechnologies has driven a correspondingly rapid growth of research that presents enormous potential for fulfilling the practical requirements of solid state hydrogen storage applications. This article reviews the most recent progress in the development of nanostructured materials for hydrogen storage technology, demonstrating that nanostructures provide a pronounced benefit to applications involving molecular hydrogen storage, chemical hydrogen storage, and as supports for the nanoconfinement of various hydrides. To further optimize hydrogen storage performance, we emphasize the desirability of exploring and developing nanoporous materials with ultrahigh surface areas and the advantageous incorporation of metals and functionalities, nanostructured hydrides with excellent mechanic stabilities and rigid main construction, and nanostructured supports comprised of lightweight components and enhanced hydride loading capacities. In addition to highlighting the conspicuous advantages of nanostructured materials in the field of hydrogen storage, we also discuss the remaining challenges and the directions of emerging research for these materials.     

Overview on the Development of Nanostructured Thermal Barrier Coatings

Thermal barrier coatings （TBCs） have successfully been used in gas turbine engines for increasing operation temperature and improving engine efficiency. Over the past thirty years, a variety of TBC materials and TBC deposition techniques have been developed. Recently, nanostructured TBCs emerge with the potential of commercial applications in various industries. In this paper, TBC materials and TBC deposition techniques such as air plasma spray （APS）, electron beam physical vapor deposition （EB-PVD）, laser assisted chemical vapor deposition （LACVD） are briefly reviewed. Nanostructured 7-8 wt pct yttria stabilized zirconia （7-8YSZ）TBC by air plasma spraying of powder and new TBC with novel structure deposited by solution precursor plasma spray （SPPS） are compared. Plasma spray conditions, coating forming mechanisms, microstructures,phase compositions, thermal conductivities, and thermal cycling lives of the APS nanostructured TBC and the SPPS nanostructured TBC are discussed. Research opportunities and challenges of nanostructured TBCs deposited by air plasma spray are prospected.     

Synthesis of nanostructured materials using supercritical CO<Subscript>2</Subscript>: Part I. Physical transformations

Nanostructured materials have been attracting increased attention for a wide variety of applications due to their superior properties compared to their bulk counterparts. Current methods to synthesize nanostructured materials have various drawbacks such as difficulties in control of the nanostructure and morphology, excessive use of solvents, abundant energy consumption, and costly purification steps. Supercritical fluids especially supercritical carbon dioxide (scCO₂) is an attractive medium for the synthesis of nanostructured materials due to its favorable properties such as being abundant, inexpensive, non-flammable, non-toxic, and environmentally benign. Furthermore, the thermophysical properties of scCO₂ can be adjusted by changing the processing temperature and pressure. The synthesis of nanostructured materials in scCO₂ can be classified as physical and chemical transformations. In this article, Part I of our review series, synthesis of nanostructured materials using physical transformations is described where scCO₂ functions as a solvent, an anti-solvent or as a solute. The nanostructured materials, which can be synthesized by these techniques include nanoparticles, nanowires, nanofibers, foams, aerogels, and polymer nanocomposites. scCO₂ based processes can also be utilized in the intensification of the conventional processes by elimination of some of the costly purification or separation steps. The fundamental aspects of the processes, which would be beneficial for further development of the technologies, are also reviewed.     

Pulsed radiofrequency glow discharge time-of-flight mass spectrometry for nanostructured materials characterization

Progress in the development of advanced materials strongly depends on continued efforts to miniaturizing their structures; thus, a great variety of nanostructured materials are being developed nowadays. Metallic nanowires are among the most attractive nanometer-sized materials because of their unique properties that may lead to applications as interconnectors in nanoelectronic, magnetic, chemical or biological sensors, and biotechnological labels among others. A simple method to develop self-ordered arrays of metallic nanowires is based on the use of nanoporous anodic alumina (NAA) and self-assembled nanotubular titanium dioxide membranes as templates. The chemical characterization of nanostructured materials is a key aspect for the synthesis optimization and the quality control of the manufacturing process. In this work, the analytical potential of pulsed radiofrequency glow discharge with detection by time-of-flight mass spectrometry (pulsed rf-GD-TOFMS) is investigated for depth profile analysis of self-assembled metallic nanostructures. Two types of nanostructured materials were successfully studied: self-assembled NAA templates filled with arrays of single metallic nanowires of Ni as well as arrays of multilayered Au/FeNi/Au and Au/Ni nanowires and nanotubular titanium dioxide templates filled with Ni nanowires, proving that pulsed rf-GD-TOFMS allows for fast and reliable depth profile analysis as well as for the detection of contaminants introduced during the synthesis process. Moreover, ion signal ratios between elemental and molecular species (e.g., (27)Al(+)/(16)O(+) and (27)Al(+)/(32)O(2)(+)) were utilized to obtain valuable information about the filling process and the presence of possible leaks in the system.     

Hydrogen Storage of Magnesium-Based Nanocomposites System

Hydrogen storage in traditional metallic hydrides can deliver about 1.5 to 2.0 wt pct hydrogen but magnesium hydrides can achieve more than 7 wt pct. However, these systems suffer from high temperature release drawback and chemical instability problems. Recently, big improvements of reducing temperature and increasing kinetics of hydrogenation have been made in nanostructured Mg-based composites. This paper aims to provide an overview of the science and engineering of Mg materials and their nanosized composites with nanostructured carbon for hydrogen storage. The needs in research including preparation of the materials, processing and characterisation and basic mechanisms will be explored. The preliminary experimental results indicated a promising future for chemically stable hydrogen storage using carbon nanotubes modified metal hydrides under lower temperatures.