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为有效调整和控制管式炭膜(TCM)内表面的孔结构,采用浸渍法对管式炭膜进行处理,并通过调整浸渍液浓度和改变浸渍处理的次数分析浸渍对膜内孔径分布的影响。扫描电子显微镜(SEM)观察得知:浸渍处理能够有效修复管式炭膜表面上的孔缺陷。同时,浸渍前后样品的孔径分布数据揭示出管式炭膜的微孔尺寸随着浸渍液浓度和浸渍次数的增加而变小,且孔分布也随之变窄。说明通过调整浸渍条件可以实现管式炭膜孔径和孔结构的有效控制。 相似文献
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采用不同的预制体和致密化方法制备了密度不同的5种炭/炭复合材料(密度范围1.77g/cm3~1.85g/cm3)。用氧-乙炔焰对试样进行了烧蚀试验,并用SEM表征了烧蚀后材料的形貌。结果表明:烧蚀后,与乙炔焰成30o角的纤维变成楔形,而与火焰平行的纤维变成直径为3.5μm~4.5μm的针状,针状纤维更易被火焰烧蚀而钝化。部分宏观孔(直径为1.0mm~1.26mm)、针状微孔及界面裂纹等缺陷处更易被烧蚀而变成烧蚀坑。包裹纤维的沥青炭层由于热解炭基体的不连续而出现了严重的剥蚀。高密度材料(1.85g/cm3)具有良好的抗烧蚀性能。 相似文献
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飞机刹车用长寿命高摩擦特性炭/炭复合材料制备技术(英文) 总被引:1,自引:0,他引:1
以针刺炭纤维准三向结构整体毡为预制体,经丙烯气体狭缝定向流的"外热内冷"、"内热外冷"径向热梯度CVI工艺致密技术,优化组合的热解炭/树脂炭双元炭基体技术,通过调控高温处理技术等三大关键技术制备了A320系列飞机炭刹车盘材料。与现用的A320系列飞机进口炭刹车盘进行了地面台架对比试验和装机应用。结果表明:自主开发的炭刹车盘其设计着陆能量和超载着陆能量的摩擦特性与国外相当,但在高能载(RTO)刹车时,其摩擦系数提高了21%~48%,静摩擦系数提高了28%;装机应用寿命平均达到2700次以上,比国外产品寿命提高了23%,凸现出长使用寿命和高摩擦特性的特色。 相似文献
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采用6 K的预氧丝和炭纤维制备预制体,通过化学气相渗积制备炭/炭复合材料。通过偏光显微镜、拉曼光谱、纳米硬度和三点弯曲等手段研究其微观结构和力学性能。结果表明,预氧丝复合材料的基体为暗层和粗糙层炭,厚度分别为1.4-2.6μm和10.2-11.6μm;而炭纤维复合材料的基体为光滑层和粗糙层炭,厚度分别为8μm和4.4μm;预氧丝纤维的模量和硬度明显小于炭纤维,同时基体的模量和硬度随消光角的增加而降低;低模量的基体和纤维导致预氧丝复合材料的拉伸强度、拉伸模量、弯曲强度和模量分别降低了14.5%-24.2%、9.7%-19.8%、7.3%-15.4%和15.1%-18.6%;但其韧性指数却提高了224%-235%,这是高含量的粗糙层炭和纤维的石墨化收缩所致;同时提出了一个三单元复合模型用来模拟复合材料的拉伸模量,模拟误差小于9.9%。 相似文献
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本文通过一种新的合成路线合成了二茂铁功能化的氧化石墨烯(GO-EDA-Fc)。利用傅里叶变换红外光谱和扫描电子显微镜对其结构和形貌进行了表征。通过热重分析(TGA)研究了其对高氯酸铵(AP)热分解的催化性能,结果表明,氧化石墨烯和二茂铁表现出很好的协同催化效果,对AP热分解具有高的催化活性。催化效果随着GO-EDA-Fc加入量的增加而增强,当加入4wt%的GO-EDA-Fc时,AP的高温分解峰的峰值温度下降了60℃,低温分解峰的峰值也有降低。文中还对催化机制进行了研究。 相似文献
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Boyang Liu Dechang Jia Jiancun Rao Qiangchang Meng Yingfeng Shao 《Bulletin of Materials Science》2008,31(5):771-774
Hollow and solid carbon spheres were prepared by the reaction of ferrocene and ammonium carbonate in a sealed quartz tube
at 500°C. The morphology and microstructure of the product were characterized by X-ray diffraction, Raman spectroscopy, scanning
electron microscopy and transmission electron microscopy. The carbon spheres are amorphous and their diameters range from
0·8–2·8 μm. The shell thickness of the hollow carbon spheres is not uniform and ranges from 100–180 nm. It is suggested that
ammonium carbonate is crucial for the formation of carbon spheres and its amount also influences the morphology of the product.
The method may be suitable for large scale preparation of carbon spheres. 相似文献
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Hollow carbon spheres were prepared by the reaction between glucose and Zn particles at 550 °C. Scanning and transmission electron microscopies reveal that most of the spheres are about 1-2 µm in diameter, similar to the sizes of the Zn particle. The shells of the spheres are comprised of numerous hollow nanospheres with the diameter of 10-100 nm. The specific surface area of the spheres is 207 m2/g. The Zn particles act as both the reactant and the template for the micron-scale spheres, and the H2 bubbles generated during the reaction as the template for the hollow nanospheres. 相似文献
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Hollow mesoporous carbon spheres (HMCSs) have been prepared by a simplified replication route from a solid silica core/mesoporous silica shell aluminosilicate (SCMS-Al) template, which was synthesized by directly incorporating aluminum species into the mesoporous framework during template synthesis. The size of HMCSs can be tuned between 80 and 470 nm by simply changing the diameters of SCMS-Al. The HMCSs have uniform mesopores with a narrow pore size distribution (3.4-4.1 nm), and high surface area, (890-1150 m2/g) and total pore volumes (0.75-1.15 cm3/g). The techniques of N2 sorption isotherms, TEM, EDX and SEM were used to characterize the as-synthesized spheres. 相似文献
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Boyang Liu Yun Zhou Dechang Jia Pengjian Zuo Yingfeng Shao Jingwei Zhang 《Bulletin of Materials Science》2011,34(7):1707-1714
Heat treatment was carried out between 800 and 1200°C to investigate its effects on the microstructure and electrochemical properties of the hollow carbon spheres (HCSs) prepared in high-pressure argon. Samples were characterized by X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy and N2 adsorption-desorption isotherms. The graphitization of the HCSs was improved with increase of heat treatment temperature. Mesopores of ca. 4 nm in diameter were created on the HCSs after the heat treatment. The results of electrochemical performance measurements for the HCSs as anode material for lithium ion batteries indicate that the discharge capacity of the HCSs is improved after heat treatment at 800°C compared with the as-prepared HCSs and have a maximum value of 357 mAh/g and still retains 303 mAh/g after 40 cycles. However, the discharge capacity of the HCSs decreases and the cycling performance is improved with the increase of heat treatment temperature. 相似文献
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以葡萄糖为原料水热合成碳球作为模板剂,将其与TiO2纳米晶共混制备纳米多孔TiO2光阳极。采用场发射电子扫描电镜(SEM)、台阶仪、紫外-可见分光光度计(UV-Vis)等对TiO2薄膜的表面形貌、厚度和散射能力进行表征。研究发现,随着碳球含量的增加,光阳极单位体积内的表面积先增加后减小;薄膜对光的散射能力也呈现同样趋势。采用所制备的光阳极组装染料敏化太阳能电池,性能测试结果表明,随着碳球含量的增加,电池短路电流密度先增加,后减小。当碳球加入量为TiO2纳米晶质量的3%时,电池光电转换效率达到最佳为5.15%。 相似文献
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The surface of hollow glass spheres was deposited with a layer of Fe3O4 film in the open air without using ultrasound and toxic reducing reagent NaNO2; the magnetic films of Fe3O4 were characterized by XRD, SEM and EDS. The intactness of the films was remarkably affected by temperature; it is favorable for the hollow glass spheres to be encapsulated completely by the Fe3O4 magnetic films as plating temperature increased at pH 6.7. The films exhibited ferromagnetic behavior. 相似文献
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Policy-makers are developing regulation policies to drive down carbon emissions from industries. Independent remanufacturers (IRs), which remanufacture recycled products/components/parts, must manage and evaluate economic costs generated by the production under future carbon emission regulations. We present three optimisation models to determine the remanufacturing quantity that maximises the total profits under three common carbon emission regulation policies: (a) mandatory carbon emissions capacity, (b) carbon tax and (c) cap and trade. These models include sales revenue, remanufacturing cost, disposal cost, inventory holding cost, shortage cost and carbon emission cost. The max–min approach is used to solve the models, which assume limited information on demand distribution. We investigate how the three regulation policies affect remanufacturing decision-making for IRs and we also solve some numerical examples where we vary the magnitudes of incentives, penalties and stringency of constraints to provide implications to policy-makers. The results indicate that remanufacturers should aim to improve yield rate to maximise the profit irrespective of the implemented carbon emissions policy. Policy-makers should prefer the carbon tax policy, if any of the other two policies must be performed, a remanufacturing discount such as a higher carbon emission cap or lower penalty should be implemented to better promote the development of remanufacturers. 相似文献
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为探究电极制备过程对材料双电层电容可能带来的变化,以褐藻为前驱体制备多孔碳,研究了电容测试过程中碳颗粒尺寸和电极制片压力两种工艺参数对其双电层电容性能的影响规律.通过将多孔碳粉末严格筛分成5组不同的尺寸,分别制成电极并测试其充放电性能和循环伏安曲线,得到比电容随颗粒尺寸变化的规律;再选取优化尺寸的多孔碳,在4种不同的压力下制成电极片,进而研究了不同制片压力对电极电容的影响规律.研究表明,在微米级,所制电极的比电容随碳颗粒尺寸的减小显著增加,同时随制片压力的增大,比电容先增大后减小.本实验条件下,碳颗粒尺寸小于25μm、制片压力为10 MPa(对应电极片所受真实压强约619 MPa)时,得到的电极片具有最高的比电容值. 相似文献