表面氧化处理对炭纤维及炭／炭复合材料力学性能的影响

采用硝酸表面氧化法，对炭纤维进行表面氧化处理，考察了不同的氧化处理时间、温度和浓度对炭纤维及其炭纤维增强复合材料力学性能的影响，提出适宜的表面氧化处理条件是低温（室温）、浓酸（５０％～６５％），短时间（１５ｍｉｎ～６０ｍｉｎ）。     

镁合金表面处理的发展现状

综述了镁合金的表面处理方法的现状，主要有化学转化膜，化学氧化，阳极氧化，表面渗层处理，金属涂层，激光表面处理，有机物涂层等，还展望了今后的发展趋势。     

镁合金表面处理研究的进展

论述了镁合金表面处理，包括化学表面转化处理、机械表面硬化处理、强束流表面改性3方面的研究现状．着重叙述了铬化、磷化处理、阳极氧化、微弧氧化等表面处理工艺。同时，还论述了机械表面硬化处理的表面喷丸强化和滚压强化。强束流表面改性代表现代先进表面改性技术，包括离子束、激光束、电子束表面改性，国外研究较多，而国内研究相对较少，应该引起足够的重视。     

化学修饰对NiTi形状记忆合金氧化膜的影响

用X光电子能谱（XPS）研究了NiTi形状记忆合金经酸、碱处理后表面氧化膜成分和结构的变化。结果表明，未经处理的NiTi合金表面最外层氧化膜主要由TiO2、TiO和少量的Ni组成，酸、碱处理后，最外层氧化膜由TiO2、Ni2O3组成，但经碱处理后，氧化膜的厚度大大增加。     

电化学氧化对炭纤维界面性质的影响

对粘胶基炭纤维进行电化学氧化表面处理，对表面处理前后的炭纤维进行强力测试，分析表面处理条件对炭纤维强度的影响，通过测定炭纤维与几种浸润液的接触角，分析了电化学氧化表面处理对炭纤维浸润特性的影响，在电镜下观察表面处理前后炭纤维表面形貌的变化，并测其比表面积的变化，分析处理条件对其表面粗糙度的影响，通过炭纤维的拉曼散射，分析表面处理前后炭纤维表面微晶大小的变化，最后，对处理前后炭纤维的相关性能指标进行比较，分析其性能变化的机理及其性能变化对炭纤维复合材料界面粘结性能的影响。     

热处理温度对Al-2%Mg合金铸锭组织及阳极氧化表面性能的影响

为构建铝材金属组织与阳极氧化表面性能的关联性，以工业化半连续铸造工艺制备的Al-2%Mg高纯度扁锭为对象，在300～550℃温度范围内进行热处理，再进行常规参数阳极氧化处理，通过光谱仪、扫描电镜、光学显微镜、分光测色仪、雾影仪等研究了热处理温度对金属组织和阳极氧化表面性能(粗糙度、光泽度和雾影值)的影响。结果表明：随着热处理温度升高，阳极氧化后表面粗糙度逐渐降低，光泽度和成像清晰度升高，雾影值降低。这些表面性能的变化与第二相的析出及回溶密切相关。     

活塞表面状况对阳极氧化膜粗糙度的影响

分析了活塞表面经硬质阳极化处理后，其表面氧化膜产生粗糙度高低的原因，阐明了获得均匀一致氧化膜的方法。     

XPS,AFM研究沥青基碳纤维电化学表面处理过程的机制

对各向同性沥青基碳纤维进行电化学氧化表面处理,用XPS,AFM分析了碳纤维表面含氧官能团和表面微观形貌的变化过程。实验结果表明:电化学氧化处理是表面碳及其含氧官能团逐步被氧化成羧基和CO₂的过程。氧化处理首先是使碳纤维表面变得更光滑,持续氧化后才会出现沟槽,SEM的分辨率不足以表征碳纤维电化学氧化前后的表面形貌变化,而采用AFM可在纳米尺度上表征碳纤维在电化学氧化过程中的表面形貌变化。AFM和XPS的结合可表征碳纤维电化学氧化表面处理的进程。     

铸铝材料微弧氧化表面改性

微弧氧化是近几年发展起来的一项材料表面改性技术，用微弧氧化技术处理铸铝材料在其表面可以形成几十至上百微米的陶瓷氧化层。经X射线衍射分析该氧化层具有α相和γ相Al2O3结构，使表面硬度提高到800—1000HV，大大改善了铸铝表面的耐磨、耐蚀、耐压绝缘和抗高温冲击特性，在发动机活塞和电熨斗中得到了很好的应用。     

多孔NiTi合金的化学氧化处理表面改性研究

在H2O2+HCl溶液中对多孔NiTi合金进行了化学氧化处理表面改性。利用EPMA、SEM、原子吸收光谱对合金表面氧化膜的组成、形貌及化学氧化处理前后的Ni离子释出进行了研究。结果表明,经过H2O2+HCl溶液化学氧化表面处理后合金表面Ni含量显著降低,在生理盐水中的Ni释放速率明显下降;H2O2+HCl溶液浓度和氧化时间均对合金表面氧化膜的生长有较大影响。     

A comparative study on mechanical properties of carbon fiber/PEEK composites

The aim of this work was to improve mechanical properties such as flexural strength and interlaminar shear strength (ILSS) of polyetheretherketone (PEEK) thermoplastic polymer which has very high processing temperature due to its high melting temperature. Carbon fiber (CF) surface was modified by two different methods: oxidative and non-oxidative. Piranha solution and chromate solution were used for chemical treatment (oxidative treatment), and silicone based polymers were used for polymer coating (non-oxidative). The changes on the surface structure and surface chemistry were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR), respectively. FTIR results indicate that coating fibers decreases carbon element content, whereas increases the oxygen and silicone content as well as their functional groups on the surface. Flexural strength and ILSS properties of CF/PEEK composites were measured according to ASTM D-790 and ASTM D2344, respectively.     

Effect of plasma treatment on thermal stability and magnetic properties of Nd-Fe-B series plastic magnets

In order to improve the thermal oxidative stability of the neodymium series (Nd₂Fe₁₄B) magnetic powder, plasma polymerization of benzene, styrene and acrylonitrile on the powder was carried out and its effect was examined. A strong hydrophobicity was revealed on the surface of the magnetic powder by the plasma treatment, and the thermal oxidative stability and magnetic properties of the powder were remarkably improved. Magnetic properties of the plastic magnets prepared with the magnetic powder coated with plasma polymer of acrylonitrile on the surface, were superior to plastic magnets prepared with untreated powder.     

Controlled oxidative nanopatterning of microrough titanium surfaces for improving osteogenic activity

To further enhance the biological properties of acid-etched microrough titanium surfaces, titania nanotextured thin films were produced by simple chemical oxidation, without significantly altering the existing topographical and roughness features. The nanotextured layers on titanium surfaces can be controllably varied by tuning the oxidation duration time. The oxidation treatment significantly reduced water contact angles and increased the surface energy compared to the surfaces prior to oxidation. The murine bone marrow stromal cells (BMSCs) were used to evaluate the bioactivity. In comparison, oxidative nanopatterning of microrough titanium surfaces led to improved attachment and proliferation of BMSCs. The rate of osteoblastic differentiation was also represented by the increased levels of alkaline phosphatase activity and mineral deposition. These data indicated that oxidative nanopatterning enhanced the biological properties of the microrough titanium surfaces by modulating their surface chemistry and nanotopography. Based on the proven mechanical interlocking ability of microtopographies, enhancement of multiple osteoblast functions attained by this oxidative nanopatterning is expected to lead to better implant osseointegration in vivo.     

石墨纤维阳极氧化表面处理的研究

本文研究了PAN基石墨纤维在四种铵盐电解液中阳极氧化表面处理的工艺条件.用SEM和XPS技术分析了处理前后纤维表面形态的变化,通过复合材料的层间剪切强度(ILSS)对表面处理前后石墨纤维与环氧树脂之间界面粘结强度的改善进行了评价.     

Comparison of short carbon fibre surface treatments on epoxy composites: I. Enhancement of the mechanical properties

Pitch-based short carbon fibres were treated by both a gaseous oxidation and a cryogenic treatment approach. It was found by scanning electron microscopy that the fibre surface roughness was increased by various oxidative conditions, whereas the fibre diameter was reduced by the cryogenic treatment. In both cases, appropriate treatments could effectively improve the mechanical properties in their epoxy composites due to the enhanced fibre–matrix interfacial bonding.     

聚苯乙烯热降解过程中表面炭化层的形成及其作用

基于体积排除色谱实验结果，详细分析了聚磷酸铵，硫酸铵，合成分子筛Y改性的聚苯乙烯在塑化混合过程和热降解过程中分子量及其分布的变化规律，由降解特性参数推断出聚苯乙烯热降解时，这些添加剂都促进形成一定表面层，但作用明显不同。     

Surface modification of NiTi alloy and human platelet activation under static and flow conditions

The effect of surface nickel species on NiTi alloy thrombogeneity was investigated by assessment of platelet activation and whether oxidative modification of the alloy would affect platelet response. Tests were conducted under static conditions and arterial levels of shear stress. Heat treatment of the alloy at 600 °C significantly reduced surface nickel species. Under both static and flow conditions platelet activation on the heat-treated alloy was comparable to that on pure titanium and was significantly lower than that on polished NiTi. This study demonstrates that the risk of thrombotic complications associated with NiTi in vivo can be reduced through heat modification of the alloy surface to reduce surface nickel.     

Topography of carbon fibre surfaces

Scanning tunnelling microscopy (stm) has been used to study topographic features on carbon fibre surfaces. Operating at a resolution of several nanometres, stm has shown a systematic change in surface profile as a function of oxidative fibre surface treatment. The surface of the polyacrylonitrile-based carbon fibre can be seen to consist of graphitic platelets of dimensions 30 × 20 × 100 nm. The platelets protrude from, rather than lie parallel to, the fibre surface. Maximum exposure of the edge of the platelets occurs at a level of treatment known to give high chemical activity and peak interfacial shear strength. Superimposed on the platelets are slit-like pores lying transverse to the fibre longitudinal axis. At high levels of treatment average surface roughness increases dramatically, coinciding with a decline in interface bond strength.     

Surface characterization of carbon fibres and interfacial properties of carbon fibre composites

The surface characteristics of carbon fibres treated by electrochemical oxidation have been determined, and the effect of these properties on the interfacial adhesive strength (interlaminar shear strength (ILSS) and transverse flexural strength) of epoxy-matrix composites investigated. The surface properties of the carbon fibres were dependent on the nature of the electrolyte used during the electrochemical oxidative treatment. Use of a basic electrolyte resulted in an improvement of composite ILSS and transverse flexural strength due to an increase in the number of surface functional groups. On the other hand, using an acid electrolyte resulted in the ILSS increasing with the number of surface functional groups, while the transverse flexural strength decreased for composites in which the carbon fibres had a high surface oxygen content. It is concluded that the weak boundary layer derived from fissures on the surface of carbon fibres treated in an acid electrolyte decreased the transverse flexural strength.     

Deformation,yield and fracture of unidirectional composites in transverse loading: 2. Influence of fibre–matrix adhesion

The influence of the adhesion between fibre and matrix on the transverse properties of unidirectional composites was studied using a combination of experimental and numerical analyses. The interface is modelled on a nano(metre)-scale and the aim is to investigate its local influence on the ultimate macroscopic transverse properties. Fibre-to-matrix stress transfer (i.e. fibre-to-matrix surface interaction) is simulated by introducing elastic interface springs. Since these elastic springs represent the chemical (covalent) bonds formed at the interface as a result of oxidative chemical surface treatment, the micromechanical model can be directly related to the effects of this treatment. For the verification of the numerical analyses, the influence of the interface is determined experimentally by transverse testing of carbon fibre reinforced composites, using fibres that were subjected to different levels of surface treatment. A direct relation between the oxygen concentration on the surface of the fibres, the interfacial bond strength and the resulting transverse strength was found. The interface strength required to obtain perfect bonding was found to be dependent on the fibre volume fraction and at increased fibre volume fractions a higher level of adhesion is required.