纳米晶钨基重合金粉末的注射成型与固相烧结

采用高能球磨技术制备了９０Ｗ－７Ｎｉ－３Ｆｅ（质量分数,％）纳米晶钨基重合金粉末,研究了该粉末的注射成型和烧结行为,并与传统混合粉末进行了比较,结果表明,机械球磨可以有效地增加粉末喂料的固体粉末含量,改善粉末料的均匀性,并可促进团相烧结的致密化,纳米粉末注射成形坯在 １３００～１４５０℃进行固相烧结后,可得到近全致密（＞９９％）、晶粒细（３～５μｍ）、拉伸强度高（≥１１３０ＭＰａ）和几乎无变形的重合金样品     

Mo-8wt%Cu纳米复合粉末的烧结与加工

用机械合金化法制取Mo-8%Cu(质量分数)纳米复合粉末,采用液相烧结和致密化后处理工艺制备了Mo-8%Cu(质量分数)合金。通过扫描电镜对Mo-Cu液相烧结和变形加工后合金显微组织进行了分析,研究了各种工艺参数对Mo-Cu合金致密性、拉伸强度、延伸率和晶粒尺寸的影响。结果表明,高能球磨的Mo-8%Cu(质量分数)纳米复合粉末坯体,经液相烧结后,其烧结态为Mo、Cu复合网状组织,可获得相对密度高达98.6%的Mo-Cu合金,再经静液挤压变形加工处理后,可获得全致密的Mo-8%Cu(质量分数)合金,在室温静液挤压40%形变率的条件下,拉伸强度可达到576MPa,延伸率5.8%。     

放电等离子烧结Ti-Al系金属间化合物

用机械合金化法(MA)制备了Ti-45% Al纳米晶合金粉末,并对其进行放电等离子烧结(SPS),烧结时间仅为5min.用D-maxIIA型X射线衍射仪、JEM-2000EX型透射电子显微镜对粉末和烧结块体的微观组织及机械性能进行了研究.研究表明:Ti和Al的粉末随着球磨时间的延长,粉末有明显的细化趋势,球磨5h即有非晶产生,球磨20h后得到接近完全非晶相;采用SPS烧结技术,在1200℃下能够制备出较高硬度的TiAl金属间化合物块体材料.     

纳米晶Sm_2Co_(17)型块体永磁的制备及磁性能

制备了两种2∶17R型Sm-Co合金:Sm2(Fe,Cu,Zr,Co)17和纯二元Sm2Co17,并利用高能球磨和放电等离子烧结(SPS)制备了致密的纳米晶块体合金,研究了其磁性能和相结构的变化。Sm2(Fe,Cu,Zr,Co)17具有较高的矫顽力,而纯二元Sm2Co17矫顽力基本为零。但高能球磨可快速降低Sm2(Fe,Cu,Zr,Co)17合金的矫顽力。利用放电等离子烧结非晶粉末制备了纳米晶块体合金,纯二元Sm2Co17合金具有较高的矫顽力,并且具有1∶7H相结构。而Sm2(Fe,Cu,Zr,Co)17合金则因为Fe-Co相及Sm2O3相的析出,具有较高的饱和磁化强度和极低的矫顽力。     

烧结TiH_2粉末制备钛合金的工艺及组织EI北大核心CSCD

以TiH2粉末为原料,通过组元球磨混合、压制成形和烧结工艺制备钛合金。用扫描电镜对球磨过程TiH2粉末的粒度、形貌变化以及烧结CP-Ti,Ti-6Al-4V合金的组织形貌进行了观察;采用热重分析方法研究了TiH2粉末脱氢的特性;用热膨胀技术研究了TiH2,TiH2-Al-V两种粉末压坯的烧结致密化特性。结果表明:TiH2粉末经过球磨后迅速变细,其粒度随球磨时间的延长而减小,粉末形貌由原来的不规则形状逐渐变为等轴状;TiH2粉末在烧结过程的脱氢将使α-Ti产生强烈收缩、同时因脱氢后获得的新鲜钛表面所发生的快速粘接而使烧结体迅速致密、得到相对密度大于99%的烧结坯体;TiH2-Al-V粉末压坯在烧结时因为伴随着合金元素的溶解而使其烧结致密特性不如纯TiH2粉末压坯的好;TiH2粉末经过成型、烧结脱氢工艺可获得典型的等轴状纯钛组织,TiH2-Al-V粉末经过相同工艺可获得典型的层片状α+β钛合金组织、且合金元素分布均匀。     

4J42 Invar合金粉末注射成形工艺研究

以羰基Fe,Ni粉为原料,蜡基聚合物为粘结剂,采用粉末注射成形技术制备了4J42 Invar合金零件.研究了粉末注射成形Invar合金的脱脂及烧结工艺.结果显示:"溶剂脱脂 热脱脂"工艺能有效快速地实现粘结剂的完全脱除;经1350℃氢气烧结,可以获得致密度98.5%,30～300 ℃内平均热膨胀系数为4.5×10-6 K-1、漏气率＜1.4×10-9 Pa·m3·s-1的PIM 4J42 Invar合金.金相显微组织及XRD分析表明合金为单一稳定的奥氏体(γ相)组织.     

纳米相复合Al-Sn合金的反应球磨制备及性能研究

利用反应球磨制备Al-SnO_2-MgH_2粉末,然后通过压制和烧结制备出高热稳纳米相复合结构Al-Sn合金。运用X射线衍射仪(XRD)和扫描电镜(SEM)等研究反应球磨制备的纳米相复合Al-Sn合金的组织和性能。结果表明:采用两步法和添加MgH_2组元的方式所制备的机械合金化(MA)Al-SnO_2-MgH_2复合粉末,经压制和600℃烧结,合金中的SnO_2几乎全部被还原成单质Sn,并呈现双尺度结构。其中,共生反应形成的纳米级Sn粒子和Al_2O_3颗粒均匀弥散地分布在Al基体中,显著提高了合金的硬度,从而使合金表现出低的摩擦系数和磨损量。     

Fe86Zr5.5 Nb5.5 B3非晶合金的超高压烧结成型

为了获得致密的块状Fe86Zr55Nb55B3纳米晶合金,研究了高压快速烧结工艺参数对样品致密度和α-Fe相晶粒尺寸的影响.结果表明:快淬球磨破碎非晶粉末在5.5 GPa/3min烧结条件下,当Pw=1150 W后,可获得相对密度为98.3%、单相α-Fe纳米晶(16.3 nm)块体合金,且随着Pw和t的增加,样品相对密度和α-Fe相晶粒尺寸均略有增加,样品典型的比饱和磁化强度σs和矫顽力Hc分别为119.6 emu/g,63.8 Oe.     

Fe70Cr8Mo2Si5B15非晶合金SPS烧结及磁性能

研究了SPS烧结温度对球磨熔体快淬Fe70Cr8Mo2Si5B15粉末的烧结块体合金组织结构与磁性能的影响.结果表明(1)在30MPa/5min条件下,当烧结温度从850℃提高至1000℃时,样品相对密度从95.8%增加到98.9%;(2)烧结样品主要组成相为α-Fe相,尚存在少量的第二相金属间化合物,且其α-Fe相平均粒晶尺寸处于纳米级范围;(3)随着烧结温度的提高,这些样品合金的比饱和磁化强度σs增加,矫顽力Hc随之降低.     

球磨时间对碳热还原AlON粉体相组成的影响

以纳米γ-Al2O3和活性炭为原料,采用碳热还原法合成AlON粉体,研究原料粉末在行星式球磨机上的球磨时间对合成粉体物相组成的影响规律。结果表明,在2~24 h内混合原料粉末时,延长原料粉末的球磨时间可有效细化活性炭,提高混合粉末的比表面积,提高Al2O3和活性炭混合的均匀性,有利于纯相AlON粉体的合成,而对于球磨时间较短的原料粉末,可以通过提高烧结温度或延长保温时间促进AlON相形成。经24 h球磨的原料粉末在1 750℃碳热还原60min获得的纯相AlON粉体,在1 880℃无压烧结制备了最大红外透过率为81%的AlON透明陶瓷(3 mm厚样品)。     

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.