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使用金红石相的二氧化钌做填充物的导电硅橡胶具有较好的压阻敏感性和可重复性,可作为一种潜在的压敏传感器材料。本文利用此种导电硅橡胶良好的线性压阻特性,制备了导电硅橡胶阵列,设计开发了压敏传感阵列信息采集分析系统。硬件电路以89C52单片机为核心,控制多路选通开关为导电硅胶阵列提供电压激励,并读取激助数据通过RS232串口发送给上位机。基于Matlab上位机程序用于控制整个系统工作,读取、分析处理单片机收集的数据,生成静态的三维柱状图像来反应硅胶阵列各传感单元受压阻值变化的情形。经实验检测该系统可以在低速率采样的情况下实现压敏传感阵列各传感单元非均匀压力分布成像的要求。 相似文献
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采用静电组装技术,制备"葡萄串"结构的炭黑(CB)/多壁碳纳米管(MWCNT)(CB/MWCNT)纳米复合材料,并以其作为导电填料,经混炼、压延和硫化后,制备柔性导电硅橡胶(SR)复合材料。分别以透射电子显微镜,扫描电子显微镜和压力-电阻测试研究不同配合比和掺量的CB和MWCNT的组装效果、分散状态和压阻特性。结果表明,CB和MWCNT的体积配合比为3∶2条件下,静电组装效果最好,静电组装形成的"葡萄串"结构,可以提高CB/MWCNT/SR的导电性和压阻特性,CB/MWCNT/SR的渗流阈值为22%,施加25N压力条件下,电阻率下降约30%,CB/MWCNT/SR表现出良好的压阻特性。 相似文献
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纳米Si薄膜由大量的超微Si晶粒和大量的晶粒间界面区组成。这一特殊的结构造成纳米Si薄膜具有较大的压阻效应。本文讨论了薄膜微结构对其压阻效应的作用。认为纳米Si薄膜材料是一种优秀的传感器材料。 相似文献
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水热法制备的纳米钌在空气中600℃退火30min获得粒径小于20nm金红石结构的导电二氧化钌。为了提高导电粒子在硅橡胶中的均匀分布,用乙烯基硅烷偶联剂对氧化钌表面进行改性,将改性的二氧化钌与硅橡胶复合制得导电硅橡胶。利用透射电子显微镜对颗粒的分布做了形象的分析。复合材料的低温电导测量表明,材料玻璃化转变显著地改变了宏观电导行为。 相似文献
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通过比较不同长径比的多壁纳米碳管复合硅橡胶的渗流特性发现长径比大于10000(长200μm,直径20nm)的长纳米碳管具有与长径比小于100(长2μm,直径20nm)的短纳米碳管显著不同的渗流特性,测量发现:随着导电相质量分数的增加,短纳米碳管呈现压阻系数由正到负的变化规律,而长纳米碳管即使导电相体积分数较低时也未呈现单调正的压阻系数,通过比较TEM和SEM照片,渗流曲线图以及对实验结果的分析,表明导电相的形貌对弹性体复合材料的压阻特性有很大影响。测量还表明对应最显著压阻变化率的质量分数长,短纳米碳管复合硅橡胶明显高于短纳米碳管复合硅橡胶,并且具有更高的压阻重复性,其在高体积分数下的高压阻敏感性、高补强作用及高压阻重复性使得该材料能用于柔性力敏传感器。 相似文献
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The optimum joining parameters for the friction joining of aluminium-based metal–matrix composite (MMC) materials are examined.
The properties of MMC/MMC, MMC/alloy 6061 and alloy 6061/alloy 6061 joints are derived following detailed factorial experimentation.
The mechanical properties of the joints are evaluated using a combination of notch tensile testing and also conventional tensile
and fatigue testing. The frictional pressure has a statistically-significant effect on the notch tensile strength of joints
produced in all base material combinations. The upset pressure has only a statistically-significant influence on the notch
tensile strength properties of alloy 6061/alloy 6061 joints. The notch tensile strengths of MMC/alloy 6061 joints are significantly
lower than MMC/MMC and alloy 6061/alloy 6061 joints for all joining parameter settings. The fatigue strength of MMC/MMC joints
and alloy 6061/6061 joints are also poorer than the as-received base materials.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
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Many applications of structural materials involving composites include impact or dynamic loading in a humid environment. Composite materials are known to degrade when subjected to humid conditions, and therefore the humidity confounds the difficulty of determining the high strain rate behavior of composites. Several researchers have found that water absorption by composites causes degradation of matrix dominated quasi-static properties. However, very little is known of the effect of absorbed moisture on the high strain rate properties of polymer matrix composites, that are useful in the automotive, aerospace, and naval applications of composite structures. A Split-Hopkinson Pressure Bar facility is used herein to study the effect of absorbed moisture in high strain rate tests (200–1200/s) of a unidirectional IM7/8551-7 graphite/epoxy composite. The study includes dry, medium, and saturated moisture conditions. The tests show significant variation of high strain rate properties from static properties, and the reasons are identified. In addition, a better understanding of the effect of the matrix and fiber/matrix interface on the high strain rate properties of composites is achieved. 相似文献
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The physical properties of composite materials 总被引:3,自引:0,他引:3
D. K. Hale 《Journal of Materials Science》1976,11(11):2105-2141
In this review, the physical properties of composite materials are discussed; however, discussion of the mechanical properties
has been excluded except when necessary for the consideration of properties such as thermal expansion or swelling and shrinkage.
One of the main aims in the review has been to show how the theoretical and experimental information that is already available
may be used (a) to design and construct composite materials with predetermined physical properties and (b) to ensure that
the physical properties of composite materials are properly measured and properly defined. 相似文献
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Aluminum (Al) matrix composite materials reinforced with carbon nanotubes (CNT) and silicon carbide nanoparticles (nano-SiC) were fabricated by mechanical ball milling, followed by hot-pressing. Nano-SiC was used as an active mixing agent for dispersing the CNTs in the Al powder. The hardness of the produced composites was dramatically increased, up to eight times higher than bulk pure Al, by increasing the amount of nano-SiC particles. A small quantity of aluminum carbide (Al(4)C(3)) was observed by TEM analysis and quantified using x-ray diffraction. The composite with the highest hardness values contained some nanosized Al(4)C(3). Along with the CNT and the nano-SiC, Al(4)C(3) also seemed to play a role in the enhanced hardness of the composites. The high energy milling process seems to lead to a homogeneous dispersion of the high aspect ratio CNTs, and of the nearly spherical nano-SiC particles in the Al matrix. This powder metallurgical approach could also be applied to other nanoreinforced composites, such as ceramics or complex matrix materials. 相似文献
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以神经脱细胞基质(NAM)凝胶作为载体,在多孔脱钙骨内表面负载BMP-2,制备新型复合骨修复材料。采用扫描电镜观察材料微观结构,结果表明脱钙骨基质(DBM)复合负载BMP-2的脱细胞基质凝胶后有利于细胞粘附;力学检测结果显示脱钙骨未复合神经脱细胞基质凝胶时,材料的抗压强度为(1.04±0.44)MPa,脱钙骨复合神经脱细胞基质凝胶之后,抗压强度为(1.00±0.30)MPa,材料复合凝胶前后力学性能改变不明显;模拟体内环境,检测不同时间点复合材料中的BMP-2缓释性能,复合材料可缓慢释放BMP-2至少一个月;在材料内部种植MC3TE-E1细胞,共培养14天,CCK-8、碱性磷酸酶检测表明负载BMP-2的神经脱细胞基质凝胶复合脱钙骨材料能够促进细胞增殖和成骨分化。神经脱细胞基质凝胶/BMP-2/钙骨复合材料具有潜在的骨修复应用前景。 相似文献
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采用热压工艺制备了UHMWPE/纳米SiO2弹性复合材料,实验考察了弹性复合材料的冲蚀特性,分析了UHMWPE/SiO2纳米复合材料的冲蚀磨损机理。结果表明:纳米SiO2含量为10%左右时,弹性复合材料的抗冲蚀性能最好,射流冲击角在30°左右时,冲蚀率达到峰值;冲蚀率与射流速度呈指数变化关系, 纳米SiO2含量为10%时,复合材料的冲蚀速度指数n为2.03;水流含沙浓度达到1.92kg/m3以后,材料冲蚀率随含沙浓度的增长趋势开始变得平缓;冲蚀率随沙粒粒径的增大而增大;纳米SiO2含量为10%左右时,弹性复合材料的冲蚀率较纯UHMEPE降低了30%,只有45#钢的1/16。UHMWPE/纳米SiO2弹性合材料的冲蚀机理主要是犁削和唇片的断裂。 相似文献
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Wear behaviour of aluminium matrix composites is characterized by the dry spindle wear test under various conditions (volume
fractions of reinforcements, sliding distances and speeds). Wear resistance of composites is improved due to the presence
of reinforcements, but no noticeable improvements are observed in the wear resistance with more than 20% addition of reinforcements.
To analyse wear mechanisms, wear surfaces are examined by scanning electron microscopy (SEM). The major wear mechanisms of
discontinuous metal matrix composites (MMC)s are strongly dependent on sliding speeds. Dominant mechanism is the adhesive-abrasive
wear at low and intermediate sliding speeds, and melt wear at high sliding speeds. Weight loss is linearly increased with
the sliding distance. The effect of reinforcements' orientations on wear behaviours is also discussed. 相似文献
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Alexander Tregub Hannah Harel Gad Marom Claudio Migliaresi 《Composites Science and Technology》1993,48(1-4):185-190
The purpose of this study is to provide insight into the microstructural factors that affect the flexural fatigue performance of carbon-fibre-reinforced poly(ether ehter ketone) (PEEK) composites. Specifically, the effect of the degree of crystallinity on the mechanical properties is examined at two crystallinity levels of the as-received composites (35%) and of quenched composites (10%). Higher static flexural strength and modulus as well as longer fatigue life are observed for the higher crystallinity level. By varying the loading angle with respect to the fibre direction it is shown that the crystallinity effect is not matrix dependent alone. Rather, a strong effect is evident in the fibre direction, which is attributed to the influence of the transcrystalline layer formed on the fibre surface in the high-crystallinity material. As a result, the longitudinal fatigue life at 1·7GPa of the 35% crystallinity material is three orders of magnitude higher than that of the 10% crystallinity composite. 相似文献
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The effect of thermal exposure in an atmospheric environment for up to 1 year on the flexural performance, under both static and fatigue loading, of a glass fiber/carbon fiber hybrid polymer matrix composite material was evaluated. It was found that exposure to a temperature near, but below, the glass transition temperature resulted in diminished flexure strength as well as reduced fatigue performance. The magnitude of property reduction was, in general, proportional to the amount of aging time, and was found to be dictated by the dominant aging mechanism. Scanning electron microscopy revealed that the modest reduction in mechanical properties at intermediate aging times was predominantly attributed to thermal oxidation, while for longer aging times thermal aging (dimensional relaxation) was the primary cause for the substantial reduction. Dimensional relaxation of the composite was measured at several isothermal aging temperatures, from which, the activation energy of the aging process was determined. This work provides insight into the evolution of mechanical properties as a function of aging time in an atmospheric environment for a hybrid polymer matrix composite. 相似文献
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聚乙烯醇缩丁醛/纳米TiO2复合材料的制备及性能研究 总被引:1,自引:0,他引:1
制备了不同聚乙烯醇浓度的聚乙烯醇缩丁醛(PVB),利用偶联剂和超声波分散法对纳米TiO2进行了表面处理,用共混法制备了PVB/纳米TiO2复合材料.采用FT-IR、XRD、SEM等测试手段表征了复合材料的红外吸收性能、光学性能、结构和微观形貌,测试了复合材料的力学性能.结果表明:由于纳米TiO2粒子的加入,复合材料的韧性得到明显提高,其断裂伸长率为纯PVB的6~8倍左右,同时使PVB/TiO2纳米复合材料具有良好的紫外线屏蔽性能.该材料的制备方法简便、易于操作,具有一定的工业应用前景. 相似文献