硬质颗粒对等离子熔覆碳化钨/多主元合金复合硬面涂层组织与耐磨性能的影响

采用等离子熔覆技术制备分别以铸造WC颗粒和烧结WC-Co球粒为硬质颗粒、以多主元合金为黏结相的2种硬面复合涂层,采用X射线衍射仪、扫描电镜、摩擦实验等手段,研究不同硬质颗粒对硬面复合涂层组织和耐磨性能的影响。结果表明：FeCrNi/WC-Co复合涂层中M₆C的体积分数为20.1%,低于FeCrNi/WC复合涂层中M₆C的体积分数(28.4%)。烧结WC-Co颗粒的热力学稳定性高,其WC的溶解程度低于铸造WC颗粒,可有效减少脆性M₆C碳化物的析出。FeCrNi/WC-Co复合涂层的耐磨性能优于FeCrNi/WC涂层。FeCrNi/WC-Co涂层中较少的M₆C相可避免涂层因脆性断裂而过早剥落,保证硬质相颗粒的完整性,提升硬面涂层的耐磨性能。     

浸锌-热浸锌沉没辊专用喷涂粉末的制备及涂层性能

采用球磨-制粒-烧结法研制热浸锌沉没辊专用喷涂粉末,采用超音速火焰喷涂法(SFS)制备涂层,研究喷涂粉末及涂层性能。结果表明,所制备的粉末为圆球形,流动性好,沉积效率高,与常规WC-Co涂层粉末相比,热浸锌专用涂层粉末中含有大量的η相。本工作研制的喷涂粉末所制涂层与基体的结合强度大于62 MPa,涂层中孔隙度仅1.2%。涂层中粘结相以η相形式存在。对采用热浸锌专用喷涂粉末制备的涂层进行现场使用考察,其使用寿命为国内常规WC-Co涂层使用寿命的近4倍。     

石墨烯增强WC-Co硬质合金的制备和力学性能研究

采用机械搅拌和静电吸附工艺制备了氧化石墨烯/WC-Co复合粉体,并对复合粉体的微观形貌进行了表征。利用放电等离子烧结(spark plasma sintering,SPS)技术制备了石墨烯/WCCo硬质合金,对复合材料的力学性能进行了测试分析。机械搅拌制备的氧化石墨烯/WC-Co复合粉体经过SPS烧结后得到的硬质合金横向断裂强度和维氏硬度为1 850 MPa,1 830,与不添加石墨烯的WC-Co硬质合金相比分别提高了3.9%,5.8%。静电吸附制备的氧化石墨烯/WC-Co复合粉体经过SPS烧结后得到的硬质合金横向断裂强度和维氏硬度为1 980 MPa,1 850,与不添加石墨烯的WC-Co硬质合金相比分别提高了11.2%,6.9%。     

发动机汽缸内壁新型耐磨涂层研究

针对发动机汽缸内壁制备耐磨涂层替代汽缸套的发展趋势,研制了一种新型铁基复合粉末,并利用大气等离子喷涂技术制备了复合耐磨涂层,测试了该涂层的结合强度、显微硬度以及摩擦磨损性能,并与不锈钢涂层的性能进行对比,结果表明,涂层平均显微硬度由337.3Hv0.1提高到464.15Hv0.1,平均结合强度由33.85MPa提高到43.63MPa,涂层的摩擦系数由0.04～0.05降低到0.01～0.02,该复合涂层耐磨减摩性能明显优于不锈钢涂层。     

热处理对等离子喷涂Ni基非晶/晶态涂层性能的影响

应用扫描电子显微镜（SEM）、X射线衍射仪（XRD）和差示扫描量热仪（DSC）研究了等离子喷涂NiCrBSi非晶／晶态复合涂层的微观组织及晶化行为，并探讨了热处理对涂层结合强度和显微硬度统计分布的影响。结果表明：喷涂态涂层为典型的层状结构，含有两类不同的层片。涂层中非晶相的晶化过程分两步进行，析晶温度范围分别为497～560℃和590～660℃。在200～400℃热处理1h，涂层与基底结合强度提高，400℃时达最大值47．3±4．7MPa；500～700℃热处理1h，结合强度变差，随温度升高而下降。喷涂态和200～400℃热处理涂层的显微硬度Weibull分布为双模态分布，揭示了层片的双态性；由于非晶相析晶，涂层500～700℃热处理后变为单模态分布。综合分析热处理对结合强度和显微硬度的影响程度表明，500℃热处理1h，涂层的综合性能较优。     

等离子喷涂NiCrBSi合金涂层的高温性能

根据高温涂层要求,采用等离子喷涂工艺制备NiCrBSi合金涂层试样,对涂层成分、组织、硬度、粘结强度、冷热疲劳性能、抗热震性能及常温和高温摩擦磨损性能进行了检测,对其结果进行了分析讨论.结果表明:等离子喷涂NiCrBSi合金涂层具有良好的粘结强度和抗高温氧化、耐高温磨损性能.     

超细及纳米WC-Co复合粉的低成本短流程制备及应用

综述了在超细及纳米WC-Co粉末的制备研究方面国内外的相关研究进展,系统介绍了北京工业大学硬质合金研究组在研究开发超细及纳米WC-Co复合粉的原位反应合成技术、超细及纳米复合粉在金属陶瓷防护涂层及烧结硬质合金块体材料中的应用等方面开展的系列工作和取得的研究结果。以合成的WC-Co复合粉为原料,制备的超细结构硬质合金涂层、超细晶及纳米晶硬质合金块体材料均具有优良的综合性能。     

NiCr过渡层对高速火焰喷涂WC-Co涂层摩擦磨损性能及疲劳磨损性能的影响

WC-Co涂层作为一种性能优异的涂层,逐渐被应用于轧辊的表面防护,目前大量实验研究的有热喷涂、激光熔覆制备WC-Co涂层。本文提出用高速火焰喷涂(HVOF)在常用轧辊材料Q235钢表面制备WC-Co涂层,同时在WC-Co涂层和基体之间加入NiCr过渡层。利用SEM、XRD、摩擦磨损测试、疲劳磨损测试等测试方法,对涂层形貌结构以及各项性能与无过渡层涂层进行对比研究。结果表明,加入NiCr过渡层后,WC-12Co+NiCr、WC-10Co-4Cr+NiCr涂层硬度分别为1059.64 HV_0.3、1016.96 HV_0.3,比WC-12Co涂层(960.01 HV_0.3)、WC-10Co-4Cr涂层(1012.20 HV_0.3)更高。WC-12Co+NiCr涂层的磨损率(5.19×10^-15 m³·(N·m)^-1)远低于WC-12Co涂层(6.59×10^-15 m³·(N·m)^-1     

一种阻燃隔热复合功能涂层性能研究

为提高航空发动机推重比、效率以及有效载荷,钛合金工程应用技术在发动机多部件的设计与研制中得到重视。针对钛合金极易发生的"钛火"问题及承受高温特性不能满足特殊零部件设计要求,开展具兼具阻燃与隔热性能的复合功能涂层十分必要,德国MTU航空发动机公司(MTU Aero Engines GmbH)开发出具有阻燃、封严性能的复合功能涂层,已经应用于航空发动机的压气机叶片和机匣,并取得了良好的效果。本文采用微弧脉冲离子表面改性技术与高能等离子喷涂工艺制备了具有阻燃特性的Ti_(40)Zr_(25)Ni_3非晶材料层和具有隔热特性的YSZ隔热一体化复合功能涂层,重点研究了该复合功能涂层的隔热能力、阻燃特性以及结合强度等关键性能。试验表明,采用微弧脉冲离子表面改性技术与高能等离子喷涂工艺制备的Ti_(40)Zr_(25)Ni_3非晶材料阻燃层与YSZ隔热复合功能涂层具有较高的结合强度,平均结合强度达到36.3MPa;阻燃改性层与基体间的界面存在微冶金结合的特征大大提高了涂层使用的可靠性;当正面火焰温度为达到600℃时,制备有复合功能涂层试样平均隔热温度达到了70℃;无复合功能涂层的试样在350℃条件下即发生燃烧现象,而制备有阻燃、隔热复合功能涂层试样在750℃条件下仍然具有良好的阻燃能力。     

热处理对超音速火焰喷涂 NiCoCrAlY 涂层组织性能的影响

采用超音速火焰喷涂制备了NiCoCrAlY合金涂层,采用真空热处理工艺对涂层进行了后处理,研究了热处理前后涂层的结构形貌、界面以及涂层结合强度的变化。研究结果表明:热处理后涂层的缺陷和孔隙由8.3%降低至1.4%;SEM和EDS分析表明,涂层与基材之间发生了元素互扩散,涂层与基体形成了约20μm的扩散层,涂层的结合强度由42.1MPa提高到55.6MPa。热处理后,涂层/基体界面形成的扩散层改善了界面结合状态,有助于消除界面处的残余应力,并形成冶金结合,从而提高涂层的结合强度。     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.