共查询到20条相似文献,搜索用时 62 毫秒
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结合扫描电镜与电子能谱分析了稀土元素对无铅钎料显微组织的影响.结果表明,当无铅钎料中的稀土添加过量,会诱发锡须在无铅合金表面的自发生长.在向Sn-9Zn-0.5Ga基体合金中添加0.7%(质量分数)的稀土元素镨(Pr)后,仅需室温时效12 h,合金组织中的稀土相表面即发生了锡须的自发生长.随着时效时间的延长,锡须会继续长大,其最终长度可达100μm.最后对过量稀土元素添加导致锡须生长的力学原因作了初步探讨,分析认为稀土相氧化所产生的微观压应力可能为锡须的生长提供了驱动力. 相似文献
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碳纤维的表面改性研究进展 总被引:8,自引:0,他引:8
综述了近年来碳纤维的表面改性及纤维微观结构和物理化学性能研究进展,其中主要包括氧化处理、涂覆处理和射线、激光、等离子体处理,并对碳纤维的研究与生产进行了分析与展望。 相似文献
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SUN Shoujin WEI Yongliang LIU Min LI Minjun Institute of Metal Research Academia Sinica Shenyang China research associate Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1993,6(11):369-373
The secondary reinforcement,crbon whiskers,may grow on the surface of parent rein-forcement,carbon fibres,by chemical vapour growth from acetylene using Fe salt ascatalyzer.The optimal growing temperature is about 1000℃,and while the concentra-tion of catalytic solution is appropriate,the carbon whiskers may deposite uniformly andlink each other on the parent carbon fibre surface.If the temperature or concentration istoo high,the coarse clusters of carbon may deposite on the fibre surface.The mechanismof carbon whisker growth is believed that the carbon atoms in vapour phase dissolve inthe Fe salt drops over fibres,then the solid carbon grains precipitate on the fibre surface. 相似文献
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1.IntroductionTitaniumcarbideisknowntobenotonlygoodelectricandthermalconductorbutalsosuperhardceramicmaterialwithahighmeltingpointandgreathardness[1--2].Withhighstrength,TiCwhiskerscanbeusedassatisfactoryreinforcingmaterialsinbothmetalmatrixcomposites(MMC)andceramicmatrixcomposites(CMC).Infact,comparedtothecommonlyusedwhiskerssuchasSiCandSt3N4,thenewlydevelopedTiCwhiskerhajsmuchhigherstrength,especiallyatelevatedtemperature,aswellasbetterchemicalstabilityandcompatibilitywithaluminamatrix… 相似文献
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碳纤维表面SiO2涂层的制备及其在镁基复合材料中的应用 总被引:2,自引:0,他引:2
利用Sol-Gel方法,通过优化溶胶的配置、纤维提拉过程和干燥烧结等工艺过程,在碳纤维表面制备出均匀的、无裂纹的SiO2涂层.采用SEM、XPS和TEM表征了碳纤维表面SiO2涂层的结构、形貌、元素分布以及涂层碳纤维/镁基体的界面结构.结果表明,涂覆SiO2的碳纤维,抗氧化能力提高,拉伸性能略有降低,但与镁基体复合后其拉伸强度降低了20%.SiO2涂层改善了Mg对碳纤维的润湿能力,有效地促进了熔融Mg液对碳纤维的浸渗. 相似文献
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WANG Chengfu YING Meifang FENG Yi ZHANG XiaogunHefei University of Technology. Hefei China 《金属学报(英文版)》1994,7(3):157-160
The electric contact is always made of silver and graphite,the electric conductivity of con-tact materials decreases as the graphite content increased.The hardness of silver-graphiteis low,for example,the hardness of the 3wt% graphite-silver is HB 24.5-39.8MPa,andthe electric conductivity,is 72% IACS.The present work reports the similarity of electricconductivity for the 3wt% short carbon fibre-Ag composite and 3wt% graphite-silver.However,the hardness of the short carbon fiber-Ag composite is two times harder thanthat of graphite-silver. The specific gravity of graphite is 2.2g/cm~3,and that of carbonfibre is 1.75g/cm~3,so the 3wt% short carbon fibre-Ag composite contact will still save5-7%Ag.The electric life of Ag-carbon fibre is much higher than silver-graphite at thesame Ag contact. 相似文献
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氧化铝涂层是满足高温工业环境的最佳保护性氧化膜之一,能够有效保护钢材料在高温、强腐蚀环境下发生的腐蚀。随着工业的发展,水或者水蒸汽广泛存在于氧化铝膜的各类服役环境中,如何使氧化铝涂层在含水蒸汽的高温环境中保持优异的力学性能和寿命是工业中面临的一个重要的问题。本文综述了含水气氛对合金氧化铝的稳定性、生长动力学、膜的结合力和对氧化铝膜表面形貌的影响。 相似文献
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1.IntroductionInrecentyears,newtechniquesfOrinsitufabrication0faluminummatrixcompos-itesreinforcedwithavarietyofceramicreinforcementshavebec0meattractivefr0manec0nomicstandpoint.Thisisbecallseonecalltakeadvantage0fconventionallyestab-lishedpr0cessingtechnologiesf0rproducinglarge-scalecastingsandf0rsubsequentmetal-working.Someofthesetechnol0giesincludeselfpropagatinghigh-temperaturesynthesis(SHS),exothermicdispersion(XD),contactreacti0nandreactivegasinfiltrati0n[1-4].M0rerecently,wearellsing… 相似文献
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GE Yunlong LIU Qingmin ZHOU Jing CHANG Xin HU Zhuangqi Institute of Metal Research Academia Sinica Shenyang China Associate Professsor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1991,4(1):17-20
Amorphous Bi(Pb)-Sr-Ca-Cu-O strips of types(1112)and(2212)were made by means ofnon-equilibrium solidification of melt-quenching method,On the surface of glassy strip,theflexible(2212)superconducting whiskers have been obtained.The growth and feature ofsuperconducting whiskers were studied in detail. 相似文献
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F.C.Zhang ) B.T.Hu ) L.X.Zhang ) C.F.Lin ) ) Department of Materials Science Engineering Yanshan University Qinhuangdao China ) Institute of Metal Research The Chinese Academy of Sciences Shenyang C 《金属学报(英文版)》1999,12(5):1069-1072
1.IntroductionSinceIijimadiscoverednanocarbontubein1991.Theseonedimensionalnanomaterialshaveimportantbasestudyvalueandpotentialapplicationvaluebecauseoftheirspecificstructurecharactersandnewphysicalpropertiesdissimilartothebasematerials,nowtheyar… 相似文献