超声表面滚压技术制备梯度纳米结构材料

介绍了超声表面滚压技术（USRP）在制备梯度纳米结构材料中的应用。USRP技术能在材料表面构建梯度纳米结构层并引入残余压应力,同时显著降低材料表面粗糙度并提升表面均匀性。讨论了与USRP加工工艺及过程密切相关的微观结构演变和表面特性,分析了不同材料体系及工艺参数对USRP处理的影响规律。研究表明,采用合适的USRP处理工艺可改善材料表面的力学性能,即硬度,强度,耐磨性及抗疲劳性能等,而腐蚀/氧化行为则更依赖于材料的组织结构、表面完整性、应力状态、不同的腐蚀介质及服役环境等因素的综合作用。此外,对USRP制备梯度纳米结构材料面临的一些基础科学问题和工业应用探索进行了讨论和展望。     

激光表面改性有机高分子材料的研究进展

有机高分子材料具有质轻、易成型、成本低等优点,在汽车、电子等领域有广泛的应用,但有机高分子材料的原始表面多数呈现化学惰性、表面能低,导致其应用受限。激光表面改性技术具有柔性化程度高、区域选择性好、可三维加工等诸多优势。简要综述了激光表面改性有机高分子材料的性能变化、机理和应用的国内外研究进展,表明通过激光改性可以在有机高分子材料表面形成诸如凸起、凹坑、沟槽、多孔和周期性结构等微观形貌,并使表面化学成分发生显著变化,进而影响其表面润湿性、表面能、吸附性、颜色和/或减阻等性能,这主要与有机高分子材料的自身特性、激光改性参数以及改性环境等因素密切相关,而且通过控制激光改性参数,还有可能实现对上述表面性能变化的精密调控。激光表面改性有机高分子材料在理论研究和实际应用中都具有巨大的价值,但目前对于激光表面改性有机高分子材料的理论研究落后于应用研究,还应进一步加强对改性技术和机理的探索与研究。     

模具表面金刚石化碳处理

中国某大学正在研究模具表面金刚石化(Piamod-arbon)处理工艺,目的是提高成形模具的表面寿命。目研究的重点是:(1)使用金刚石化碳进行表面处理的可行性,从而展冷成形模具技术,提高模具寿命。(2)研究表面碳镀的技术参数(如电压、煤气和压),这些参数影响碳镀表面的机械性能。对经碳镀的模具寿命进行比较。金刚石化碳是一种硬而有柔性的抗磨材料,为惰性而耐腐蚀的材料,原子结合紧密、抗离散,同时也有活性物特点。这样,由于表面低吸附性而摩擦力小,这种材料可在低温下存在。大量金属、陶瓷材料、玻璃和塑料都可以镀这种材料而不影响其特性。模…     

含硫原油加工过程腐蚀环境分析

含硫原油加工过程中主要存在三种不同的腐蚀环境,即蒸馏装置的HCl-H2S-H2O、催化裂化装置的HCN-H2S-NH3-H2O、高温(240℃以上)环境,由此造成生产装置设备的严重腐蚀。通过分析三种环境各自不同的腐蚀机理,介绍了相应的设备防护措施,以及目前国内外先进的表面防腐蚀处理技术,指出炼油装置设备腐蚀防护的重点是合理选择耐腐蚀材料与加强表面防护。     

高效、节能、环保--发展稀土表面改性技术大有前途

材料表面改性技术近几年发展迅速,但如何进一步提高效能,降低处理温度,缩短工艺时间,节约能耗,减少废液废气排放,对环境更友好,始终是材料工作者致力研究的问题。     

多巴胺表面修饰在医疗领域的研究进展

多巴胺(DA)及其聚合物聚多巴胺(PDA)含有邻苯二酚基团、氨基等大量活性官能团,使其具有良好的黏附性、生物相容性、反应活性和还原性,被广泛用于医疗器械材料、船舶材料、传感器件材料、药物运输等材料表面的改性,其中对医疗器械材料表面的修饰研究前景尤为广阔。分析了多巴胺的理化特性及相关功能,归纳了多巴胺在生物工程材料上的应用,包括增强材料的骨组织再生能力和提高材料表面细胞的黏附、增殖等。在此基础上,重点综述了近年来多巴胺在医疗领域的改性研究进展,其中多巴胺对骨修复及骨移植材料的修饰包括复合材料和高分子材料等,多巴胺对牙种植体及牙修复材料的修饰包括纳米金属材料和合金材料等,多巴胺对新型医疗材料的修饰包括人工血管、人工韧带材料和医用膜材料等。阐述了改性材料的优缺点和作用,以及多巴胺如何对材料表面进行改性来弥补材料的缺陷。针对不同材料的多巴胺改性,分别从制备方法、实验对比结果等方面进行归纳。最后展望了多巴胺表面修饰技术的发展方向。     

中国金属材料表面纳米化技术取得突破性进展

表面氮化是工业中一种广泛应用的材料表面处理技术，在表面氮化过程中材料或部件的表面形成一层硬质氮化物以提高表面使役行为，如耐磨性、耐蚀性等。钢铁的表面氮化处理往往需要在高温下(高于500℃)进行，处理时间较长(长达数十小时)，不仅耗能，更重要的是许多材料和工件在如此高温下长     

陶瓷模具材料的表面改性技术及应用

全面综述了表面镀层、表面复合、表面涂覆等表面改性技术在各类陶瓷模具中应用、研究的现状。指出：表面改性技术既能发挥陶瓷材料的高硬度、高耐磨和耐高温等的优势，又能发挥金属基体高强度、高韧性的特点，从而使得陶瓷模具材料具有良好的使用性能，具有广阔的应用前景。今后研究的重点是如何通过表面改性工艺的控制和复合层材料的合理选择和设计，使得所形成的陶瓷复合层与金属基体结合强度高，硬度高，既减摩又耐磨。     

论金属材料表面技术的现状及发展方向

材料表面技术，是指对材料表面进行涂镀、扩渗和处理的技术。     

表面涂层技术的进展

表面涂层技术的进展王小萍（北京化工管理干部学院）材料的表面改性是材料学研究中的一个重要课题，它对提高材料的使用性能，扩大材料的使用范围，实现材料功能复合等方面具有重要意义。表面涂层技术作为材料表面改性的重要手段能够制备各种特殊功能的涂层，用少量的材料...     

Fractal characterization of wear-erosion surfaces

Wear erosion is a complex phenomenon resulting in highly distorted and deformed surface morphologies. Most wear surface features have been described only qualitatively. In this study wear surfaces features were quantified using fractal analysis. The ability to assign numerical values to wear-erosion surfaces makes possible mathematical expressions that will enable wear mechanisms to be predicted and understood. Surface characterization came from wear-erosion experiments that included varying the erosive materials, the impact velocity, and the impact angle. Seven fractal analytical techniques were applied to micrograph images of wear-erosion surfaces. Fourier analysis was the most promising. Fractal values obtained were consistent with visual observations and provided a unique wear-erosion parameter unrelated to wear rate.     

钢筋混凝土的环境侵蚀与表面防护技术

论述了钢筋混凝土在不同环境下的侵蚀类型与机理,总结了钢筋混凝土劣化的主要原因.在此基础上,分析了钢筋混凝土表面防护技术的必要条件,并阐述了目前钢筋混凝土的表面防护技术的类别、材料及其特点.     

Multisecular corrosion behaviour of low carbon steel in anoxic soils: Characterisation of corrosion system on archaeological artefacts

In the context of the prediction of materials behaviour used in the nuclear waste storage, the understanding of iron corrosion mechanisms in anoxic environment is of great importance. Information can be obtained using complementary analytical tools. Interactions between burial soil and archaeological artefacts are studied by performing on site soil measurements. Moreover, archaeological artefacts are studied on transverse sections using a combination of microbeam techniques. The specific interest of this project lies in the study of ferrous thick corrosion layers formed in anoxic environments.     

A semi-analytical method to compute surface elastic properties

In this paper, a semi-analytic method is developed to compute the surface elastic properties of crystalline materials. Using this method, surface elastic properties, such as the intrinsic surface energy density, intrinsic surface stress and surface elastic stiffness, are given analytically in terms of the inter-atomic potentials of the material. To evaluate these analytical expressions, one needs to know only the equilibrium (or relaxed) positions of the atoms near the free surface. The relaxed positions of the atoms near the free surface can be obtained by conducting a standard molecular simulation of a free surface. In comparison with existing methods, the semi-analytical method developed here reduces the amount of computation significantly. More importantly, because of the analytical nature of the method, it can provide us with a much better understanding of the surface characteristics. To illustrate the methodology, low-index surfaces (1 1 1), (1 0 0) and (1 1 0) of face-centered cubic metals Cu, Ni, Ag, and Pd are considered. A full set of data on surface elastic properties including the intrinsic surface energy, the intrinsic surface stress tensor, and the surface elastic stiffness tensor have been computed and are reported here for these materials. It is believed that such a complete set of surface property data for these materials are new to the literature.     

Heterogeneous electrochemical characteristics of biofilm/metal interface and local electrochemical techniques used for this purpose

Biofilms on metal surface in an aqueous environment is a complex electrochemical system. The heterogeneous electrochemical characteristics of biofilm/metal interface and local electrochemical techniques used for this purpose are discussed in this work. The techniques presented in this work include microelectrode, scanning vibrating electrode, the wire beam electrode method, and scanning electrochemical microscopy. Two potentially useful techniques, localized electrochemical impedance spectroscopy and scanning Kelvin probe force microscopy, are also discussed. The advantages and limitations of these techniques are summarized. A new approach: numerical simulation of micro‐electrochemical heterogeneity of biofilm covered metals is introduced.     

海洋微生物腐蚀的研究进展

介绍了国内外海洋微生物腐蚀研究的最新进展,讨论了海洋中影响金属腐蚀的几类微生物,评述了微生物腐蚀研究中涉及的微生物的培养,测量方法以及表面分析手段;简介了不锈钢,铜和铜合金,镍合金的微生物腐蚀的特征和最新研究进展,并展望了微生物腐蚀研究的发展趋势。     

Three-dimensional electron backscattered diffraction analysis of deformation in MgO micropillars

Small-scale testing is extensively used to study the effects of size on plasticity or characterise plastic deformation of brittle materials, where cracking is suppressed on the microscale. Geometrical and experimental constraints have been shown to affect small-scale deformation and efforts are underway to understand these better. However, current analytical techniques tend to possess high resolution in only one or two dimensions, impeding a detailed analysis of the entire deformed volume. Here electron backscattered diffraction in three dimensions is presented as a way of characterising three-dimensional (3-D) deformation at high spatial resolution. It is shown that, by reconstruction of compressed and then successively sliced and indexed MgO micropillars, this 3-D technique yields information complementary to μ-Laue diffraction or electron microscopy, allowing a correlation of experimental artefacts and the distribution of plasticity. In addition, deformation features which are difficult to visualise by standard scanning electron microscopy are easily detected, for example where only small surface traces are produced or minimal plastic strain can be introduced before failure in brittle materials.     

IFHTSE Global 21: heat treatment and surface engineering in the twenty-first century: Part 9 – Influence of materials science on heat treatment and surface engineering

Abstract

Significant progresses have been made in the past decades in the discipline of materials science, which include, but not limit to, the synthesis of new materials, advancement in analytical and experimental techniques, sustainable and environmentally friendly processing technologies, computational material science and nanotechnology. These developments have major influences on the research and application of heat treatment and surface engineering, and provide new opportunities to engineer the surfaces of new and conventional materials using advanced technologies to meet the ever increasing demands in surface and subsurface related properties. This survey gives a brief review on some aspects of heat treatment and surface engineering which keep pace with new developments in materials science. The specific areas being examined include: (i) advanced analytical techniques; (ii) sustainable and environmentally friendly technologies; (iii) surface engineering of emerging new materials such as intermetallic compounds, shape memory alloys and biomaterials; (iv) the search for superhard coatings and surface nanostructured materials; (v) mathematical modelling of surface engineering systems.     

Comparison of intrinsic and acquired nonlinear effects in photothermal detection of delaminations in composites

Photothermal techniques are based on the harmonic detection of thermal waves at the surface of a material. Several factors may render the thermal wave response nonlinear. Such are intrinsic characteristics as the strong dependence of the thermal properties on temperature and/or acquired features as defects that may open and close (‘kiss bonding’) at the excitation frequency. Several theoretical and experimental studies have been performed to estimate and evaluate the existence of such overtones in the response and the potential exploitation for nondestructive testing. This work is focused on composite materials. Based on precedent experimental studies, this theoretical analysis shows the comparison of the rival effects in the generation of overtones. A finite element model was developed to solve the ‘intrinsic source case’ in comparison to an analytical approximative simulation for the case of overtones originating from the oscillation of a defect (delamination) size. Both models are reduced to a single dimension.     

TIG torch surfacing of metallic materials – a critical review

This article aims to review and highlight the significant features and development of tungsten inert gas (TIG) torch surfacing of metallic materials. The emphasis is on the surfacing method for metallic materials using a melting processing route. The fusion surfacing methods such as powder injection, wire feed and pre-place powder are elaborated. The comparisons of TIG torch surfacing methods to electron beam welding, laser cladding and thermal spraying are tabulated to give a better understanding of each surfacing method. The application of TIG torch surfacing techniques on various metallic materials is reviewed based on a number of studies from previous researchers. The significance of processing variables of TIG torch surfacing techniques is highlighted with the heat input and welding speed being the most influential factors. This paper also shows the potential application of TIG torch surfacing for the hybridisation of composite coated hard surface layer formation in metallic materials.