Al2O3-Cu纳米复合材料的制备工艺及强化机理

用粉末冶金法制取了Al2 O3 Cu纳米颗粒增强复合材料 ,测试了不同增强体体积下的力学性能并观察了其形貌。在一定范围内 ,随着增强体体积的增加 ,其硬度也在增加。并用镶嵌残余应力模型计算解释了Al2 O3 Cu纳米复合材料的强化机理。     

偶联剂表面处理对复合材料静态力学性能的影响

利用纳米SiO2对氰酸酯树脂(CE)进行增韧改性,采用冲击强度、弯曲强度测试及扫描电子显微镜等手段研究了纳米SiO2含量对纳米SiO2/CE复合材料静态力学性能的影响;在此基础上,分别选用小分子偶联剂KH-560和大分子偶联剂SEA-171对纳米SiO2进行表面处理,进一步研究了界面结构对纳米SiO2/CE复合材料静态力学性能的影响,初步探讨了其作用机理。结果表明,纳米SiO2(尤其是以大分子偶联剂处理后的纳米SiO2)的加入提高了复合材料的冲击强度和弯曲强度。当SiO2质量分数为3%时,复合材料的冲击强度、弯曲强度达到最大,增幅分别为61.9%,44.2%。     

Enhanced through-plane thermal conductive properties of Ag/rGO nanocomposite

High thermal conductivity of nanocomposite-based polymer matrix is one of the most important keys in developing many heat exchanger instruments. Here, we report a novel nanocomposite system based on silver-coated reduced graphene oxide (Ag/rGO) in silane cross-linked low-density polyethylene (XLPE) matrix with unprecedented through-plane thermal conductivity. Compared to the virgin rGO, Ag/rGO nanocomposite showed 67% higher thermal conductivity due to the Ag nanoparticles (NPs) decoration. The Ag NPs within the nanocomposites are believed to act as a thermal conductor among rGO nanosheets and eventually enhance the heat conduction in 3D manner.     

基于欠膨胀射流的SiO2/环氧树脂纳米复合材料制备方法研究

为实现在不添加分散剂的情况下将纳米粒子均匀分散在液相物料中,提出了一种基于欠膨胀射流的液相物料纳米粉添加分散方法.该方法利用欠膨胀射流将纳米粒子以气-粉微气泡的形式分散到液相物料内部,并利用微气泡受高频挤压爆破释放的能量,以及气泡膨胀过程产生的超声波效应和高拉伸场效应来实现纳米粉在液相物料中以纳米尺度粒子分散.设计了相应的分散系统,进行了无分散剂下纳米SiO2/环氧树脂添加分散实验.通过TEM和Tg测试对实验样品进行了表征,结果表明,分散相粒径在15～30nm之间,SiO2纳米颗粒均匀地分散在环氧树脂中.Tg温度比只经过一般高速机械搅拌得到的复合材料提高了约18℃.该方法解决了SiO2纳米粉颗粒在环氧树脂中的团聚问题.     

聚苯乙烯/Al2O3纳米复合材料的选区激光烧结成形工艺研究

选区激光烧结法制备聚苯乙烯/A l2O3纳米复合材料的工艺实验表明,在其他激光烧结工艺参数一定,合理匹配激光功率和扫描速度的条件下,直接制备出了无翘曲变形、外形轮廓完好的聚苯乙烯/无机纳米块体复合材料,烧结块体密度最大达到了1.04 g/cm3,致密度大于95%。试样缺口冲击韧性最大达到了12.1 kJ/m2。     

纳米材料制备研究的若干新进展

综述了纳米材料领域在纳米金属（或合金）粉末、纳米管和纳米纤维（纳米棒）、纳米材料的自组装、纳米半导体材料以及纳米复合材料等制备方面的最新进展,并对一些新方法相对于一般纳米材料制备方法的优点进行了比较．     

A study of compaction of composite particles by multi-particle finite element method

We study the compaction of composite mixture of soft and hard micro-/nano-size particles using multi-particle finite element method. In this method, each particle is fully discretized into finite element mesh. Local non-uniform contact deformation and non-uniformity stress chains transmitted through the composite are well illustrated. In this work, we focus on the effect of inter-particle friction and volume fraction of hard particles on compaction pressure. Results of closed die compaction of 400 two-dimensional monosize spherical particles of zero and 40% volume fraction hard particles are presented. The results show that compaction pressure increases with inter-particle friction and volume fraction of hard particles. The predicted compaction pressure curves are in good agreement with experimental data and other models.     

有机蒙脱土增强聚氯乙烯手套材料的制备与表征

通过在乳液聚氯乙烯（PVC）中添加有机蒙脱土（OMMT）来研究OMMT对其各项性能的影响。结果表明：OMMT对乳液PVC／邻苯二甲酸二辛酯（DOP）／OMMT纳米复合材料的力学性能有一定的改善效果;对复合材料的抗增塑剂迁移效果明显;在耐酸和耐碱试验中,未添加OMMT的复合材料的拉伸强度和撕裂强度分别降低了7．3％、5．i％和5．5％、13．3％,而添加3份OMMT后,仅仅降低了2．5％、2．6％和1．5％、4．2％,效果显著。     

ZrO2增韧Al2O3／SiCnano复合陶瓷的力学性能及微结构

本文对Al_2O_3/SiC nano ZrO_2(3Y)复相陶瓷的力学性能和微结构进行了研究,探讨了ZrO_2(t)应力诱导相交增韧机制和纳米粒子增韧机制相互迭加的可能性。结果表明:适量的第二相纳米粒子ZrO_2(3Y)加入对材料的微结构有很大影响,同时对材料的力学性能的提高作出贡献。     

Closely packed Si@C and Sn@C nano-particles anchored by reduced graphene oxide sheet boosting anode performance of lithium ion batteries

Both silicon and tin are promising anodes for new generation lithium ion batteries due to high lithium storage capacities (theoretically 4200 mA h g-1 and 992 mA h g-1,respectively).However,their large volumetric expansions (both are above 300 ％) usually lead to poor cycling stability.In this case,we synthesized closely packed Si@C and Sn@C nano-particles anchored by reduced graphene oxide (denoted as Si@C/Sn@C/rGO) by the way of solution impregnation and subsequent hydrogenation reduction.Sn particles with a diameter of 100 nm are coated by carbon and surrounded by Si@C particles around 40 nm in average diameter through the high-resolution transmission electron microscopy.Expansions of Si and Sn are alleviated by carbon shells,and reduced graphene oxide sheets accommodate their volume changes.The prepared Si@C/Sn@C/rGO electrode delivers an enhanced initial coulombic efficiency (78％),rate capability and greatly improved cycle stability (a high reversible capacity of nearly 1000 mA h g-1 is achieved after 300 cycles at a current density of 1000 mA g-1).It can be believed that packing Sn@C nano-particles with Si@C relieves the volume expansion of both and releases the expansion stresses.Sn@C particles enhance anode process kinetics by reducing charge transfer resistance and increasing lithium ion diffusion coefficient.The present work provides a viable strategy for facilely synthesizing silicon-tin-carbon composite anode with long life.