基于短切碳纤维表面均匀包覆Cu层工艺的C_f/Cu复合材料制备与表征

为制备能够在Cu基体中分散均匀的大体积分数的短碳纤维(C_f)/Cu复合材料,采用电化学法在C_f表面进行了镀Cu处理,用平行Cu片做阴极代替长碳纤维束,得到镀层均匀光洁的镀Cu短C_f。在此基础上,将2V,30min条件下的C_f/Cu复合丝直接采用放电等离子烧结(SPS)制备了46vol%C_f/Cu复合材料(试样1),又用Cu粉与未包覆的C_f直接混合再烧结制备了另一种46vol%C_f/Cu复合材料(试样2)。利用XRD和SEM分别研究了C_f/Cu复合丝和C_f/Cu复合材料的物相成分、表面及断口形貌,对C_f原丝、C_f/Cu复合丝以及用2种方式制备的C_f/Cu复合材料进行了力学性能研究。结果表明:C_f/Cu复合丝拉伸载荷-位移曲线上出现了较大幅度的波动,这与其表面镀Cu层受力时发生不连续断裂有关。试样1组织的均匀性及力学性能均优于试样2。与Cu相比,用2种不同方法制备的C_f/Cu复合材料的抗拉强度低于Cu,但屈服强度比Cu高。     

基于碳纤维表面修饰制备碳纤维织物增强聚苯硫醚(CFF/PPS)热塑性复合材料

碳纤维织物增强聚苯硫醚(CFF/PPS)复合材料是重要的热塑性航空复合材料,其难点为提高碳纤维(CF)与基体的浸润性及界面强度。探讨了CF表面修饰对CFF/PPS界面结合强度的影响,对比了热处理去浆及三种表面修饰剂对碳纤维单丝及CFF/PPS复合材料的改性效果。采用X射线光电子能谱分析(XPS)、扫描电子显微镜(SEM)、单丝强度测试、复合材料静力学测试和动态力学分析等手段对CF表面修饰效果进行评价,建立了基于CF表面修饰制备高性能CFF/PPS热塑性航空复合材料的方法。制备的复合材料层间剪切强度达91.4MPa,弯曲强度953.7MPa,拉伸强度797.4MPa,模量68.4GPa,冲击强度58.3kJ/m2,用SEM观察到CF表面包覆大量PPS树脂。     

热压烧结一步法制备C_f/Cu复合材料的组织和性能

为了简化工艺及提高性能,采用热压烧结一步法制备Cf/Cu复合材料。研究了Cf/Cu复合材料的界面反应原理、微观形貌及不同的Ti添加量对复合材料密度、硬度、强度等性能的影响。结果表明:Cu-C-Ti三元体系,在低于1100℃,碳纤维表面生成TiC层,该反应层降低了液态Cu与碳纤维的润湿角,改善了Cu与碳纤维的界面结合。探讨了TiC层的形成机制,提出了溶解在Cu液中的Ti原子与碳纤维接触生成TiC的微观反应模型。TiC层的形成有利于提高复合材料的性能。当Ti的质量分数为16.7%时,Cf/Cu复合材料的综合性能最好,其肖氏硬度高达HS66.94,抗弯强度为97.59 MPa。     

聚醚酰亚胺修饰碳纤维及其对聚碳酸酯基复合材料界面和性能的影响

以聚醚酰亚胺(PEI)为修饰剂,对氧化后的碳纤维(CF)进行表面修饰,并通过红外光谱、X射线光电子能谱和扫描电镜(SEM)表征了表面修饰效果。结果表明,氧化处理使CF表面PEI修饰层更加均匀。考察了PEI和CF含量对CF增强聚碳酸酯(PC/CF)复合材料力学性能、导热性能及耐热性能的影响,发现PEI修饰层使PC/CF复合材料的拉伸强度比未经修饰的PC/CF提高了35.2%,维卡软化温度(VST)进一步上升了约2℃,热导率最大提高了13.1%。拉伸样条断面的SEM图确认了PEI修饰层改善了复合材料的界面附着效果。结合复合材料中CF的长度分布统计及样品断面的SEM图对PC/CF复合材料的性能表现进行了分析。     

用镀Cu-Fe碳纤维制备的铜基复合材料

用连续电镀法在碳纤维表面上先镀铜后镀铁,制备了镀Cu—Fe双镀层的碳纤维,研究了碳纤维与Cu—Fe双镀层的高温相容性,并用镀Cu—Fe的碳纤维制备了单向、混向铜基复合材料。测试了复合材料的弯曲强度、线热膨胀系数和电阻率。     

化学气相浸渗2DCf/(SiC-C)复合材料的微观结构与强韧性

采用等温等压化学气相浸渗法(ICVI)制备了二维碳纤维增韧碳化硅碳二元基复合材料(2D Cf/(SiC-C)).利用扫描电镜(SEM)和背散射电子成像(BSE)研究了其基体的微观结构,并与二维碳纤维增韧碳化硅陶瓷基复合材料(2D Cf/SiC)比较了室温力学性能和断口形貌.结果表明:2D Cf/(SiC-C)复合材料的基体是由SiC与热解碳(PyC)组成的多层结构,PyC基体层分布均匀而连续,且与SiC基体层结合紧密.纤维束内部PyC基体层较厚的2D Cf/(SiC-C)复合材料具有较高的强韧性,其拉伸强度、断裂应变、断裂韧性和断裂功分别比2D Cf/SiC复合材料的提高了3%、142%、22%和58%.SiC与PyC组成的多层基体使2D Cf/(SiC-C)复合材料的纤维在拔出过程中发生了两次集中拔出,且第一次集中拔出的纤维对复合材料的强韧性起主要作用.     

纳米SiC-MoS2/Ni基复合电刷镀层组织与耐磨性能

通过对纳米SiC颗粒进行表面修饰处理,采用电刷镀技术制备纳米SiC-MoS2/Ni基复合刷镀层,分析探讨了纳米SiC和MoS2的含量对镀层形貌和耐磨性能的影响。结果表明,镀液中加入经表面修饰的纳米SiC颗粒可以提高镀层硬度,同时在干滑动磨损试验条件下,纳米SiC-MoS2复合刷镀层具有良好的耐磨减摩性能。     

两种碳纤维增强Cf/BN-Si3N4复合材料性能对比

采用XRD,XPS和SEM对T300和T700两种碳纤维的物相结构、表面成分以及表面形貌进行了分析.分别以两种碳纤维编织件为增强体,采用先驱体浸渍一裂解(PIP)工艺制备了Cf/BN-Si3N4复合材料,并对其力学性能和微观结构进行分析.结果表明,两种碳纤维的石墨化程度、表面活性均相近,表面形貌差别很大.两种纤维增强的复合材料密度相当,但力学性能以及断裂行为有明显区别.与T300碳纤维增强的复合材料相比,T700增强的复合材料弯曲强度更高,弹性模量略低,具有更好的韧性.碳纤维表面状态的差异是纤维与基体的结合强弱以及复合材料力学性能不同的主要原因.     

含Fe、Ni的CF/Cu复合材料

用连续电镀法在碳纤维上镀铜后又镀Fe、Ni,制备了镀Cu-Fe、Cu-Ni的双镀层碳纤维。用它们分别制备了CF/Cu-Fe、CF/Cu-Ni复合材料,与V_t相近的CF/Cu复合材料相比,CF/Cu-Fe,CF/Cu-Ni复合材料的电阻率和弯曲强度均有不同程度的提高。通过调整碳纤维的体积分数V_f,复合材料的热膨胀系数可以明显降低。单向复合材料在断裂后,碳纤维没有明显拔出,CF/Cu-Ni复合材料的断口上,基体出现塑性变形,CF/Cu-Fe复合材料断口上的碳纤维表面上分布着不连续的瘤状物。用透射电镜分析了这两种复合材料的界面结构。CF/Cu-Fe复合材料中碳纤维表面上的不连续瘤状物是多晶的Fe₃C相,CF/Cu-Ni复合材料的界面区则是Cu-Ni固溶体相。它们对碳纤维与铜基体的结合分别起着反应型和溶解型的强化作用。     

碳纤维增强Cu-Ti3SiC2复合材料的研究

采用电镀Cu碳纤维(Cf)与化学镀Cu的Ti3SiC2粉及Cu粉进行湿混,通过真空热压烧结法制备Cf增强的Cu-Ti3SiC2复合材料.研究了其致密度、电阻率、维氏硬度随Cf,Ti3SiC2含量变化的规律.实验结果表明,Ti3SiC2体积含量为20%,Cf体积含量为8%时,制备的Cf增强Cu-Ti3SiC2复合材料综合性能最好.Cf镀Cu和Ti3SiC2镀Cu改善了它们和Cu的润湿性,从而提高了相互之间的结合强度是复合材料获得良好综合性能的基本原因.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to     

Win-Win Cooperation

正The Chinese Premier Li Keqiang's recent trip to the UK has reinforced the China-UK comprehensive strategic partnership;just as the British Prime Minister David Cameron put it,"the relationship is gaining in strength,depth and understanding"after a bucket of business deals being inked worth more than 30 billion US dollars.From the first agreement signing in 2004 to the new agreement of mutual standards recognition and adoption in     

Systematic Approach for Emerging Industry

正A national directory of standards complexes for strategic emerging sectors was recently developed and released jointly by 12governmental departments,namely,SAC,NDRC,MOST,MIIT,MEP,MOA,AQSIQ,State Forest Administration,State Administration of Science and Technology for National Defense,State Oceanic Administration and National Railway Administration.     

Strictest Pollutants Emission Standards

正Four new national standards on air pollutant emission control offi cially issued by the Ministry of Environment Protection(MEP)together with AQSIQ and SAC has been brought into force from July 1,2014.The Emission standard for air pollutants of coal-burning,oil-burning and gasfi red boilers,which is the strictest emission standard historically,will tackle the stubborn pollution problem of boilers and waste incineration in most of China’s regions.     

Instructions to Authors

New Carbon Materials is a bimonthly journal published with the permission of the Ministry of Science and Technology and of the State News and Publication Agency.The journal is sponsored by the Institute of Coal Chemistry,Chinese Academy of Sciences,and is published by Science Press.Aims and Scope     

Progress on Standards Copyright Protection

正Recently,National Copyright Administration of China(NCAC)has rewarded 215 organizations and 179 individuals for their outstanding efforts on investigating standards copyright infringement and piracy in 2013.Hua Jianhua,the Deputy-Director of National Standards Copyright Protection Workgroup Office won a third prize of the national individual award.In 2012,SAC set up the national standards copyright protection working group,and developed policies to crack down standards infringement and piracy behaviors and to strengthen standards copyright protection.