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应用环-块式摩擦磨损试验机研究不同弓网振动幅值下纯碳/铜合金和浸金属碳/铜合金2种摩擦副的载流摩擦磨损行为。试验结果表明:弓网之间在不间断地发生近似正弦规律的振动,2种摩擦副的电弧功率都随着振动幅值的增大呈现先增大后减小的趋势,纯碳滑块更容易发生起弧现象,电弧功率更大;2种摩擦副的摩擦因数都随着振动幅值的增大而减小,浸金属碳有更好的耐磨性。使用扫描电镜对滑块的磨损形貌进行观察,结果表明:在一定范围内,随着振动幅值的增大,电弧对纯碳和浸金属碳2种滑块材料的烧蚀程度均加剧;纯碳滑块电弧侵蚀的表现形式为烧蚀坑和热应力裂纹,浸金属碳滑块电弧侵蚀的表现形式为犁沟、材料剥离和烧蚀麻点。 相似文献
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通过销-盘摩擦磨损试验,研究了碳/铜摩擦副在有无电流条件下的摩擦学性能。结果表明:试验过程中摩擦副温度不断地升高,且有电流时摩擦副温度比无电流时高,滑板材料的磨损量随着温度的升高而增大;当无电流通过时,摩擦因数随温度的升高先增大后减小,当有电流通过时,摩擦因数随温度的升高而减小。观察碳滑板磨损前后表面形貌发现:磨损表面随摩擦副温度的升高变得越来越光滑;当无电流通过时,磨粒磨损和黏着磨损是主要磨损类型,当有电流通过时,磨损类型以氧化磨损和电弧烧蚀为主。碳滑板材料磨损表面EDS分析发现,元素转移和氧化现象在磨损过程中时有发生。 相似文献
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在受电弓-接触网载流摩擦磨损过程中,接触线会产生不同的横截面形状,而接触线形貌的改变可能会影响弓网间的接触关系,进而影响弓网间的载流摩擦磨损性能。为研究不同表面形貌的接触线对浸金属碳滑板载流摩擦磨损性能的影响,利用环-块式高速载流摩擦磨损试验机,研究载流条件下常规形貌、麻点形貌、斜切形貌的接触线与浸金属碳滑板的摩擦磨损性能,比较采用不同形貌接触线时的摩擦因数、电弧能量和浸金属碳滑板的磨损量、表面形貌。试验结果表明:在直流电情况下,常规接触线与浸金属碳滑板组成的摩擦副的摩擦因数最小,滑板磨损量最低;采用斜切形貌接触线时的摩擦因数最大,滑板磨损量最大。通过SEM电镜观测浸金属碳滑板表面的磨损形貌,发现接触线为常规形貌时,滑板以氧化磨损为主,有较多的氧化物产生;接触线为麻点形貌时,滑板以电弧烧蚀和磨粒磨损为主,产生了细小裂纹和烧蚀坑,有较多的磨屑和剥落层出现;接触线为斜切形貌时,滑板以电弧烧蚀为主,有大裂纹和犁沟产生,并且烧蚀区域出现了较多的白色小球。研究表明,当接触线的形貌发生改变时,会导致滑板磨耗增加并加剧接触副电弧放电,从而恶化接触副的状态。因此,当接触线磨损变形严重时,应及时进行更换... 相似文献
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两种受电靴材料与不锈钢带电接触摩擦磨损特性的试验研究 总被引:1,自引:2,他引:1
在销-盘式摩擦磨损试验机上分别进行了不锈钢/铜基烧结合金材料和不锈钢/铜石墨烧结材料接触的载流摩擦磨损行为的试验研究。在试验中记录了摩擦因数和磨损量的变化,并对磨痕形貌进行了光学显微镜观察。结果显示,电流对2种摩擦副带电接触的摩擦磨损行为有重要的影响。2种材料的摩擦因数随电流的增大而呈现截然相反的变化趋势,但两者的磨损量却随电流的增加而增大。不锈钢/铜基烧结合金材料的磨损机制主要是粘着磨损及氧化磨损。不锈钢/铜石墨烧结材料磨损机制包括磨粒、粘着磨损和电弧烧蚀,其中电弧烧蚀对磨损量的影响随电流的增大而增加。 相似文献
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采用等离子体增强化学气相沉积法在C/C复合材料基底表面制备了不同厚度的类金刚石(DLC)表面改性膜;用球-盘对磨的方式测试了C/C复合材料基底和DLC膜在干态下的摩擦磨损性能。结果表明:制备的表面改性膜具有典型的DLC结构特征,均匀致密;随着沉积时间的延长,DLC膜厚度逐渐增大,膜基结合强度依次减小;C/C复合材料基底的平均摩擦因数为0.285 8,磨损率约为1.6×10-4mm3·N-1·m-1,表面改性膜的摩擦因数较基底有较大程度的降低,在0.08~0.27之间,磨损率也降低了1~2个数量级,且沉积时间越长其摩擦因数越小、磨损率越低。 相似文献
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采用强制流动热梯度化学气相渗透法在1000~1 250℃制备了密度梯度碳/碳复合材料;借助三点弯曲试验和激光闪烁法测定了复合材料的弯曲性能与导热系数,用偏光显微镜及扫描电子显微镜观察了基体热解碳的组织结构及断口形貌。结果表明:该复合材料上层的最大密度为1.65g·cm~(-3),下层的最小密度为1.10g·cm~(-3),具有明显的密度梯度;复合材料的密度越大,抗弯强度越高;其导热系数也随密度的增加而增大;沉积温度是影响基体热解碳组织的主要因素,高温有利于粗糙层热解碳的生成,而低温有利于光滑层热解碳的生成。 相似文献
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采用薄膜沸腾气相沉积(film-boiling chemical vapor infiltration,FBCVI)工艺,制备原位碳纳米纤维增强碳/碳复合材料(carbon nanofibers-reinforced carbon/carbon composites,CNFs-C/C))。研究了致密化过程中CNFs的生长情况和催化剂的引入对材料组织结构和力学性能的影响。研究表明,致密化前期,原位生长CNFs困难;随着沉积时间延长,CNFs大量增多并被碳基体包覆,CNFs主要为碳纳米线(carbon nanowires,CNWs)。CNFs-C/C的碳基体结构为粗糙层(RL),且存在大量的生长锥。相比于未加催化剂的试样,CNFs-C/C的弯曲强度和模量分别提高了30.9%和39.1%,断裂模式为假塑性断裂。 相似文献
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Several engineering components made of carbon-based heat-resistant composites are subjected to severe erosive wear. In view of the above, the solid particle erosion behavior of two and four dimensionally reinforced carbon/carbon (C/C) composites as well as that of carbon/phenolic (C/P) composite has been characterized at the ambient temperature. The investigated C/C composites have been produced through a liquid-phase infiltration method followed by hot isostatic pressing, while the C/P composite prepegs have been cured inside an autoclave. The erosion rates of these composites have been determined for two different impact angles and two different impact velocities using silica sand with average particle diameter of 200 μm. The morphologies of as-received and eroded surfaces of test specimens have been examined with the help of scanning electron microscopy to understand the mechanism of material removal. The erosion response, erosion efficiency, and erosion micromechanisms of these composites have been studied in detail. While the erosion resistance of the C/P composite is found to be superior to that of the investigated C/C composites, the four dimensionally reinforced C/C composite have shown the highest erosion efficiency. All the composites have exhibited a semi-ductile erosion response. Their mechanical properties have little correlation with the erosion rates. 相似文献
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化工材料是化工业及工业生产制造的基本元素,各种材料的性能特点决定了复合产品加工制造质量的好坏。分析碳碳复合材料界面热力学特点,主要是为了保证化工材料性能的正常发挥,使得化工生产的流程更加顺利。采用了理论研究与生产实践相结合的方式分析了碳碳复合材料的基本性质与优势,从四大热力学定律分析了材料详细的热学特点,得出了温度高低变化是影响复合材料性能的重要因素。 相似文献
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Bao-ling Lei Mao-zhong Yi Hui-juan Xu Li-ping Ran Yi-cheng Ge Ke Peng 《Tribology Letters》2011,41(2):371-378
Three different C/C composites with rough laminar (RL) pyrocarbon, RL pyrocarbon with added resin-derived carbon, and pure
resin-derived carbon have been evaluated and tested for friction performance. A laboratory dynamometer was used to simulate
different braking speeds utilizing a single stator and rotor pair. The morphologies and microstructures of the raw materials,
wear surfaces, and wear debris at different braking levels were observed by polarized light microscopy, scanning electron
microscopy, and transmission electron microscopy. The results have shown that the friction coefficients of the three C/C composites
display the same characteristics with increasing braking speed. They increased to a maximum value at medium braking speed
and thereafter decreased with increasing braking speed, and their mean values under the same braking conditions were similar.
The C/C composite with pure resin-derived carbon showed the highest loss due to wear under all conditions, while the C/C composite
with the RL pyrocarbon showed the lowest loss. Resin-derived carbon in C/C composites does not have a significant effect on
the friction coefficient, but the wear rate increases greatly with increasing resin-derived carbon content. Wear debris is
composed of flocculent particles with polycrystalline structure, along with the matrix carbon, which is worn off directly
from the composites. 相似文献
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During the process that implant materials are used for bone replacement,the cell responses to implant materials determine the long-term stability of bone replacement.The microstructure of implant materials is considered as a critical factor that influences the cell responses.Carbon/Carbon composites(C/C composites) are novel implant materials,but there are few reports on the effect of their microstructure,especially the carbon matrixes and holes,on cell behavior.In this paper,C/C composites with different carbon matrixes are prepared by chemical vapor infiltration and pressure impregnation carbonization technique,respectively.The structure of holes is analyzed.The cell responses to C/C composites with different carbon matrixes are evaluated with MG63 osteoblast-like cells.The morphologies of MG63 osteoblast-like cells on the surface of C/C composites,especially in the holes are assessed by scanning electron microscope,and cell proliferation behavior is evaluated by 3-[4,5-dimethylthiozol-2-yl]-2,5-diphenyltetrazolium bromide(MTT) assay. The results show that MG63 osteoblast-like cells have a lamellar morphology with similar sizes and spreading areas as well as the same proliferation behaviors for C/C composites with different carbon matrixes.Carbon matrix shows unapparent influence on the cell growth behavior.Besides,MG63 osteoblast-like cells have various interactions with the holes of C/C composites.The cells stride over the holes with 6~8μm in size,and connect with each other or grow along the curvature wall of the holes with a size of 30-40μm;the cells present three-dimensional morphologies inside the holes and display circular shapes along the ridge of the holes.Diverse cell-material interactions are found according to the size and position of the holes,which provides theoretical foundation for the microstructure design of clinical C/C composites. 相似文献