化学气相沉积法制备核/壳结构Co/C纳米颗粒的结构与热稳定性

以乙酰丙酮钴为原料,采用单步金属有机物化学气相沉积法,在600~800℃温度下制备碳包覆钴的核/壳结构Co/C纳米颗粒。利用X射线衍射、透射电镜和Raman光谱仪等对合成产物的元素组成和结构进行表征,研究合成温度对产物形貌和结构的影响,分析Co/C核/壳纳米颗粒的形成机理,并通过差式扫描量热分析/热重分析研究产物的热稳定性。结果表明,不同反应温度下的产物中,Co核的粒径均在10~60 nm之间,C壳层的厚度在10~20 nm之间。随合成温度从600℃升至800℃,Co核由HCP和FCC的混合结构逐步转变为单一的FCC结构,而C层的结晶度逐渐升高。核/壳结构Co/C纳米颗粒在空气气氛下从250℃开始缓慢氧化,结晶度高的C壳层对Co核具有更好的保护作用。     

纳米镍颗粒空心纤维的制备及其表征

探索采用化学镀制备纳米镍颗粒有机复合纤维，经热解脱芯后得到纳米镍颗粒空心纤维的方法，并用SEM，TEM和XRD对其显微形貌和结构进行观测和分析。SEM观测显示，脱芯后得到的金属镍纤维为空心壳层结构，壳层完整且有微孔。XRD和TEM分析结果都表明：空心镍纤维壳层是由面心立方金属镍纳米颗粒构成σs，平均颗粒尺寸约40nm。强磁震动样品磁强仪测量纳米镍颗粒空心纤维的磁性能。为33．80emu·g^-1,He为151 Oe。研究结果表明，采用化学镀制备金属有机复合纤维脱芯，可以获得纳米镍金属颗粒构筑的空心纤维。     

碳包覆CdS纳米颗粒的光学性能研究

采用水热法制备了核壳结构的碳包覆CdS纳米颗粒(CdS@C),利用X射线衍射、高分辨透射电子显微镜和光谱仪研究了碳包覆层对CdS@C的微观结构与光学性能影响.结果表明,碳包覆CdS纳米颗粒具有明显的核壳结构,内核为六方纤锌矿结构CdS,外壳为碳层.颗粒形貌主要为球形或椭球形结构,粒度均匀,分散性良好,粒径分布在20～6...     

超细Ni-C核-壳纳米颗粒的制备及其磁学和微波吸收性能

以乙酰酮丙镍为原料,通过金属有机物化学气相沉积,合成超细Ni-C核-壳纳米颗粒。采用XRD、Raman光谱仪、TEM和多功能物理测试系统对合成的纳米颗粒的物相、结构和磁学性能进行表征。这种超细纳米颗粒外表包覆一层厚度1~3 nm的C层,内部Ni核的平均粒径为13 nm。磁学测试表明,超细Ni-C核-壳纳米颗粒的饱和磁矩为24.5 emu/g,矫顽力为65.5 Oe,远低于直径超过20 nm的Ni-C核-壳纳米颗粒的对应值。微波吸收测试表明,超细Ni-C核-壳纳米颗粒和石蜡的混合物的最小反射损失值(RL_(min))为-48.7 d B,有效带宽(BW_(eff),RL≤-10dB)为7.4 GHz,是一种非常具有潜力的微波吸收材料。     

负载纳米铁颗粒的碳纳米球的制备及磁性能研究

采用喷雾催化热解法制备出负载纳米铁颗粒的碳纳米球,研究了氢气流量对其微观结构、晶体结构和磁性能的影响.当氢气流量为3.0L/min时,所制备的碳纳米球具有洋葱状结构,外表面不光滑,其石墨层间距为0.342nm,球体中散布着直径为几个纳米到30 nm的纳米铁颗粒;当氢气流量提高到5.4 L/min后,所制备的碳纳米球具有光滑的表面,其石墨层间距增大到0.360 nm;随着氢气流量的增大,碳纳米球的矫顽力逐渐增大,饱和磁场强度和剩余磁场强度则逐渐降低.     

碳纳米球的制备研究

研究提供以脱铁蛋白(apo-ferritin)为材料,采用生物模板技术制备出的一种新型纳米碳质材料--碳纳米球及其制备方法.与国际上的研究热点碳纳米管相比,空心碳纳米球结构特殊,比重小(1.3 g/cm3)、比表面积(＞600 m2/g)大,丰富的纳米尺度空隙.空心碳纳米球在储氢、锂离子负极材料等领域应具有类似于碳纳米管的潜在的巨大应用前景.     

Ag包覆Fe复合纳米粉体的制备及导电导磁性能研究

用化学镀法,以葡萄糖和甲醛的混合液为还原剂,制备了Ag包覆Fe复合纳米粉体,并用制备的复合纳米粉作为导电导磁相,制备了导电导磁胶。用透射电子显微观察和X射线衍射表征了Ag包覆Fe复合纳米粉体的结构、形貌和粒度分布,用直流低电阻测试仪、振动样品磁强计研究了导电导磁胶的导电导磁性能。结果表明:制备的Ag包覆Fe复合纳米颗粒具有壳核结构(纳米Fe为核、Ag为壳),复合纳米颗粒粒度分布为50~120 nm,通过电镜测得Ag层的厚度约为2 nm。用Ag包覆Fe复合纳米粉制备的导电导磁胶的电阻率为2.66×10~(-4)~8.9×10~(-4)?·cm、饱和磁化强度18.5~38.6 A·m~2·kg~(-1)。     

化学镀法制备金属铜包覆纳米碳化硅

采用化学镀法制备出金属Cu包覆SiC的复合颗粒.按照一定比例配制化学镀液,控制施镀过程中体系pH 值在12 左右,施镀时间在20min 之内,并改变装载量,制备出了不同包覆度的复合颗粒.通过XRD、扫描电镜、透射电镜和EDS 等进行研究,发现纳米SiC 表面包覆上了一层金属铜层,形成了SiC-Cu 壳核复合颗粒,金属铜粒径大约为5nm.     

退火对表面纳米化后IF钢结构和织构影响

通过组织观测和织构ODF测试,研究了退火对表面机械研磨处理后的冷轧IF钢结构和织构的影响。结果表明:表面机械研磨处理后的冷轧IF钢表面层纳米晶组织具有良好的热稳定性,经850℃真空退火后,样品表面依然为晶粒取向呈随机分布的纳米晶组织。SMAT样品退火前的晶粒取向对IF钢退火织构的形成具有重要影响,取向处于a-丝织构中的晶粒是再结晶形核和长大的源泉;退火前a-丝织构组分越强,退火后形成的再结晶织构也就越强。     

中空SiC球形纳米颗粒的合成及吸波性能

特殊结构和组成是决定电磁波吸收性能的关键因素。采用自组装技术合成碳包覆二氧化硅(SiO₂@C)的球形纳米颗粒,经高温热处理后制备出中空SiC球形纳米颗粒。通过扫描电镜(SEM)和X射线衍射仪(XRD)对样品进行微观形貌分析和物相分析,采用矢量网络分析仪对样品的电磁参数进行测试,借助SiC的介电损耗以及其特殊的微观结构对其吸波性能进行调控,并模拟计算不同涂层厚度下样品的反射损耗(RL)。结果表明,随着SiO₂@C中碳含量的增加,经高温热处理后生成的SiC纳米颗粒由不规则的形状转变为中空球形纳米颗粒结构。在频率为14.06 GHz时,样品的最小反射损耗(RLmin)为-18.23 dB,有效吸收频带(RL≤-10 dB)达到了5.34 GHz,对应的涂层厚度为1.9 mm,体现出厚度薄、吸收频带宽的特点。     

China's Major Non-ferrous Metals Imports & Exports

正~~     

Zinc Production by Province in 2014

正~~     

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.