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151.
采用化学镀法在石墨基体表面沉积出Ni-Fe-P合金催化剂,通过SEM、XRD、EDX对合金催化剂进行分析表征.通过CVD法,以热处理后的Ni-Fe-P合金作为催化剂,噻吩为助催化剂,乙炔为碳源,反应温度为650℃条件下成功制备出螺旋碳纤维.研究发现所得产物全部为尺寸、形貌规整的双螺旋碳纤维,纤维长度达到毫米级,螺旋直径及单根纤维直径分别为2~3 μm、0.5~0.8μm. 相似文献
152.
碳纳米管是一种有前途的微波吸收剂,可以作为潜在的隐身材料、电磁屏蔽材料或暗室吸波材料使用.本文综述了近年来国内外通过碳纳米管碳化学镀改性、纳米管与聚合物共混、纳米管与铁磁材料杂化来制备微波吸收剂的研究成果和存在的问题,提出了碳纳米管作为吸波材料今后的发展方向. 相似文献
153.
154.
《中国航空学报》2021,34(11):243-253
Literature has demonstrated that Carbon Nanotubes (CNTs) can greatly enhance the electrical conductivity and matrix-dominated mechanical properties of fibrous composites. However, electrothermal coupling effect of CNTs on Carbon Fiber Reinforced Plastics (CFRPs) has scarcely been considered. This work prepared and introduced thin and porous CNT webs to the surface or/and interface of a CFRP to enhance its electrothermal properties. The results show that CNT webs can enhance the transverse electrical conductivities of the CFRP by 231%−519% in a current range of 50–150 mA, when compared to the base-CFRP. Also, the surface temperature of CNT webs decorated CFRP can be improved by 20.5–32.3 °C within 3 min showing a self-heating rate of 6.8–10.8 °C/min just with an applied voltage of 20–30 V, increased by 152%−177% when compared to the base-CFRP (2.7–3.9 °C/min). Also, deicing can be finished within 4–10 min with a voltage of 18 V and an input power of 246 W/m2. Moreover, the electrothermal processes nearly have no negative effect on the mechanical properties of the CFRP. The relatively low input power and short response time for deicing make the CNT webs decorated CFRP may be a potential new generation for aeronautical deicing structure. 相似文献
155.
综述了国内外聚丙烯腈基碳纤维的研究发展历程和现状,重点介绍了聚丙烯腈基碳纤维及其复合材料在导弹武器、运载火箭、卫星和航天飞机等航天领域的应用发展情况,并对国产聚丙烯腈基碳纤维的发展提出了一些建议。 相似文献
156.
采用金属辅助化学腐蚀法制备了多晶黑硅,并研究了极低浓度NaOH溶液对扩孔后黑硅结构的圆化作用及其对多晶黑硅太阳电池性能的影响。用扫描电镜(Scanning electron microscope,SEM)和量子效率(Quantum efficiency, QE)测试仪对黑硅表面形貌及黑硅电池性能进行了表征。结果表明,利用极低浓度的NaOH圆化扩孔后黑硅的尖端及棱角可以减少表面复合的影响。处理后的黑硅表面孔洞均匀且平滑,黑硅太阳电池400~900 nm可见光波段平均反射率为4.15%,批量生产的电池平均转换效率达到17.94%,比常规酸制绒工艺制备的电池平均转换效率提高了0.35%。 相似文献
157.
《中国航空学报》2022,35(11):85-112
It is an inevitable trend of sustainable manufacturing to replace flood and dry machining with minimum quantity lubrication (MQL) technology. Nevertheless, for aeronautical difficult-to-machine materials, MQL couldn’t meet the high demand of cooling and lubrication due to high heat generation during machining. Nano-biolubricants, especially non-toxic carbon group nano-enhancers (CGNs) are used, can solve this technical bottleneck. However, the machining mechanisms under lubrication of CGNs are unclear at complex interface between tool and workpiece, which characterized by high temperature, pressure, and speed, limited its application in factories and necessitates in-depth understanding. To fill this gap, this study concentrates on the comprehensive quantitative assessment of tribological characteristics based on force, tool wear, chip, and surface integrity in titanium alloy and nickel alloy machining and attempts to answer mechanisms systematically. First, to establish evaluation standard, the cutting mechanisms and performance improvement behavior covering antifriction, antiwear, tool failure, material removal, and surface formation of MQL were revealed. Second, the unique film formation and lubrication behaviors of CGNs in MQL turning, milling, and grinding are concluded. The influence law of molecular structure and micromorphology of CGNs was also answered and optimized options were recommended by considering diverse boundary conditions. Finally, in view of CGNs limitations in MQL, the future development direction is proposed, which needs to be improved in thermal stability of lubricant, activity of CGNs, controllable atomization and transportation methods, and intelligent formation of processing technology solutions. 相似文献
158.
159.
通过调整工艺条件,制得不同分散性的碳管改性环氧树脂,分别采用静置观察法、黏度法、细度法对分散性进行宏观表征。结果表明:碳管的分散性越好,环氧树脂的黏度越大、细度越低、保存时间越长;三种方法均可以表征碳纳米管的分散均匀性;黏度法和细度法可以实现碳管分散性的快速评价,但均需找出具体的评价标准。通过建立刮板细度与碳管分散性的对应关系,可以快速表征碳管的分散性,简便易行。 相似文献
160.